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shairport-sync/audio_alsa.c
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/*
* libalsa output driver. This file is part of Shairport.
* Copyright (c) Muffinman, Skaman 2013
* Copyright (c) Mike Brady 2014--2025
* All rights reserved.
*
* Permission is hereby granted, free of charge, to any person
* obtaining a copy of this software and associated documentation
* files (the "Software"), to deal in the Software without
* restriction, including without limitation the rights to use,
* copy, modify, merge, publish, distribute, sublicense, and/or
* sell copies of the Software, and to permit persons to whom the
* Software is furnished to do so, subject to the following conditions:
*
* The above copyright notice and this permission notice shall be
* included in all copies or substantial portions of the Software.
*
* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
* EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES
* OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
* NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT
* HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY,
* WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
* FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR
* OTHER DEALINGS IN THE SOFTWARE.
*/
#define ALSA_PCM_NEW_HW_PARAMS_API
#include <alsa/asoundlib.h>
#include <inttypes.h>
#include <math.h>
#include <memory.h>
#include <pthread.h>
#include <stdio.h>
#include <unistd.h>
#include "config.h"
#include "activity_monitor.h"
#include "audio.h"
#include "common.h"
enum alsa_backend_mode {
abm_disconnected,
abm_connected,
abm_playing
} alsa_backend_state; // under the control of alsa_mutex
typedef struct {
snd_pcm_format_t alsa_code;
int sample_size;
} format_record;
// This array is of all the formats known to Shairport Sync, in order of the SPS_FORMAT definitions,
// with their equivalent alsa codes and their frame sizes.
// If just one format is requested, then its entry is searched for in the array and checked on the
// device
// If auto format is requested, then each entry in turn is tried until a working format is found.
// So, it should be in the search order.
format_record fr[] = {
{SND_PCM_FORMAT_UNKNOWN, 0}, // unknown
{SND_PCM_FORMAT_S8, 1}, {SND_PCM_FORMAT_U8, 1}, {SND_PCM_FORMAT_S16_LE, 2},
{SND_PCM_FORMAT_S16_BE, 2}, {SND_PCM_FORMAT_S24_LE, 4}, {SND_PCM_FORMAT_S24_BE, 4},
{SND_PCM_FORMAT_S24_3LE, 3}, {SND_PCM_FORMAT_S24_3BE, 3}, {SND_PCM_FORMAT_S32_LE, 4},
{SND_PCM_FORMAT_S32_BE, 4}, {SND_PCM_FORMAT_UNKNOWN, 0}, // auto
{SND_PCM_FORMAT_UNKNOWN, 0}, // illegal
};
int output_method_signalled = 0; // for reporting whether it's using mmap or not
int delay_type_notified = -1; // for controlling the reporting of whether the output device can do
// precision delays (e.g. alsa->pulsaudio virtual devices can't)
int use_monotonic_clock = 0; // this value will be set when the hardware is initialised
static int32_t current_encoded_output_format; // ms 8 bits: channels; next 16 bits: rate/100;
// rightmost 8 bits: sps_format
static char public_channel_map[128] = "";
// static output_configuration_t alsa_configuration; // sample
// static output_configuration_t *current_alsa_configuration;
static volume_range_t volume_range = {0, 0};
static output_parameters_t output_parameters = {NULL};
static void help(void);
static int init(int argc, char **argv);
static void deinit(void);
static int prepare(void);
static int32_t get_configuration(unsigned int channels, unsigned int rate, unsigned int sps_format);
static int configure(int32_t requested_encoded_format, char **channel_map);
static void start(int i_sample_rate, int i_sample_format);
static int play(void *buf, int samples, __attribute__((unused)) int sample_type,
__attribute__((unused)) uint32_t timestamp,
__attribute__((unused)) uint64_t playtime);
static void stop(void);
static void flush(void);
static int delay(long *the_delay);
static int stats(uint64_t *raw_measurement_time, uint64_t *corrected_measurement_time,
uint64_t *the_delay, uint64_t *frames_sent_to_dac);
static void *alsa_buffer_monitor_thread_code(void *arg);
static void volume(double vol);
static void do_volume(double vol);
static int do_play(void *buf, int samples);
static output_parameters_t *parameters();
static int mute(int do_mute); // returns true if it actually is allowed to use the mute
static double set_volume;
audio_output audio_alsa = {.name = "alsa",
.help = &help,
.init = &init,
.deinit = &deinit,
.prepare = &prepare,
.get_configuration = &get_configuration,
.configure = &configure,
.start = &start,
.stop = &stop,
.is_running = NULL,
.flush = &flush,
.delay = &delay,
.play = &play,
.stats = &stats, // will also include frames of silence sent to stop
// standby mode
// .rate_info = NULL,
.mute = NULL, // a function will be provided if it can, and is allowed
// to, do hardware mute
.volume =
NULL, // a function will be provided if it can do hardware volume
.parameters = &parameters};
static int do_open();
static int do_close();
pthread_mutex_t alsa_mutex = PTHREAD_MUTEX_INITIALIZER;
pthread_mutex_t alsa_mixer_mutex = PTHREAD_MUTEX_INITIALIZER;
pthread_t alsa_buffer_monitor_thread;
// for deciding when to activate mute
// there are two sources of requests to mute -- the backend itself, e.g. when it
// is flushing
// and the player, e.g. when volume goes down to -144, i.e. mute.
// we may not be allowed to use hardware mute, so we must reflect that too.
int mute_requested_externally = 0;
int mute_requested_internally = 0;
// for tracking if the output device has stalled
uint64_t stall_monitor_new_frame_count_time; // when the delay was last measured
long stall_monitor_new_frame_count; // the delay when measured last plus all subsequently added
// frames
uint64_t stall_monitor_error_threshold; // if no frames have been output in a time longer than this,
// it's an error
snd_output_t *output = NULL;
int alsa_device_initialised; // boolean to ensure the initialisation is only
// done once
yndk_type precision_delay_available_status =
YNDK_DONT_KNOW; // initially, we don't know if the device can do precision delay
snd_pcm_t *alsa_handle = NULL;
int alsa_handle_status =
-ENODEV; // if alsa_handle is NULL, this should say why with a unix error code
snd_pcm_hw_params_t *alsa_params = NULL;
snd_pcm_sw_params_t *alsa_swparams = NULL;
snd_ctl_t *ctl = NULL;
snd_ctl_elem_id_t *elem_id = NULL;
snd_mixer_t *alsa_mix_handle = NULL;
snd_mixer_elem_t *alsa_mix_elem = NULL;
snd_mixer_selem_id_t *alsa_mix_sid = NULL;
long alsa_mix_minv, alsa_mix_maxv;
long alsa_mix_mindb, alsa_mix_maxdb;
char *alsa_out_dev = "default";
char *hw_alsa_out_dev = NULL;
char *alsa_mix_dev = NULL;
char *alsa_mix_ctrl = NULL;
int alsa_mix_index = 0;
int has_softvol = 0;
int64_t dither_random_number_store = 0;
int volume_set_request = 0; // set when an external request is made to set the volume.
int mixer_volume_setting_gives_mute = 0; // set when it is discovered that
// particular mixer volume setting
// causes a mute.
long alsa_mix_mute; // setting the volume to this value mutes output, if
// mixer_volume_setting_gives_mute is true
int volume_based_mute_is_active =
0; // set when muting is being done by a setting the volume to a magic value
sps_format_t disable_standby_mode_default_format;
int disable_standby_mode_default_rate;
int disable_standby_mode_default_channels;
// use this to allow the use of snd_pcm_writei or snd_pcm_mmap_writei
snd_pcm_sframes_t (*alsa_pcm_write)(snd_pcm_t *, const void *, snd_pcm_uframes_t) = snd_pcm_writei;
void handle_unfixable_error(int errorCode) {
if (config.unfixable_error_reported == 0) {
config.unfixable_error_reported = 1;
char messageString[1024];
messageString[0] = '\0';
snprintf(messageString, sizeof(messageString), "output_device_error_%d", errorCode);
if (config.cmd_unfixable) {
command_execute(config.cmd_unfixable, messageString, 1);
} else {
die("An unrecoverable error, \"output_device_error_%d\", has been "
"detected. Doing an emergency exit, as no run_this_if_an_unfixable_error_is_detected "
"program.",
errorCode);
}
}
}
static char *device_types[] = {
"SND_PCM_TYPE_HW", "SND_PCM_TYPE_HOOKS", "SND_PCM_TYPE_MULTI",
"SND_PCM_TYPE_FILE", "SND_PCM_TYPE_NULL", "SND_PCM_TYPE_SHM",
"SND_PCM_TYPE_INET", "SND_PCM_TYPE_COPY", "SND_PCM_TYPE_LINEAR",
"SND_PCM_TYPE_ALAW", "SND_PCM_TYPE_MULAW", "SND_PCM_TYPE_ADPCM",
"SND_PCM_TYPE_RATE", "SND_PCM_TYPE_ROUTE", "SND_PCM_TYPE_PLUG",
"SND_PCM_TYPE_SHARE", "SND_PCM_TYPE_METER", "SND_PCM_TYPE_MIX",
"SND_PCM_TYPE_DROUTE", "SND_PCM_TYPE_LBSERVER", "SND_PCM_TYPE_LINEAR_FLOAT",
"SND_PCM_TYPE_LADSPA", "SND_PCM_TYPE_DMIX", "SND_PCM_TYPE_JACK",
"SND_PCM_TYPE_DSNOOP", "SND_PCM_TYPE_DSHARE", "SND_PCM_TYPE_IEC958",
"SND_PCM_TYPE_SOFTVOL", "SND_PCM_TYPE_IOPLUG", "SND_PCM_TYPE_EXTPLUG",
"SND_PCM_TYPE_MMAP_EMUL"};
static int permissible_configuration_check_done = 0;
static uint16_t permissible_configurations[SPS_RATE_HIGHEST + 1][SPS_FORMAT_HIGHEST_NATIVE + 1]
[8 + 1];
static int get_permissible_configuration_settings() {
int ret = 0;
if (permissible_configuration_check_done == 0) {
uint64_t hto = get_absolute_time_in_ns();
snd_pcm_hw_params_t *local_alsa_params = NULL;
snd_pcm_hw_params_alloca(&local_alsa_params);
snd_pcm_info_t *local_alsa_info;
snd_pcm_info_alloca(&local_alsa_info);
pthread_cleanup_debug_mutex_lock(&alsa_mutex, 50000, 0);
snd_pcm_t *temporary_alsa_handle = NULL;
ret = snd_pcm_open(&temporary_alsa_handle, alsa_out_dev, SND_PCM_STREAM_PLAYBACK, 0);
if (ret == 0) {
snd_pcm_type_t device_type = snd_pcm_type(temporary_alsa_handle);
ret = snd_pcm_info(temporary_alsa_handle, local_alsa_info);
if (ret == 0) {
int card_number = snd_pcm_info_get_card(local_alsa_info);
if (card_number >= 0) {
debug(2, "output device is card %d.", card_number);
char device_name[64] = "";
snprintf(device_name, sizeof(device_name) - 1, "hw:%d", card_number);
snd_ctl_t *handle;
int err = snd_ctl_open(&handle, device_name, 0);
if (err == 0) {
snd_ctl_card_info_t *info;
snd_ctl_card_info_alloca(&info);
err = snd_ctl_card_info(handle, info);
if (err == 0) {
debug(2, "card name: \"%s\", long name: \"%s\".", snd_ctl_card_info_get_name(info),
snd_ctl_card_info_get_longname(info));
}
snd_ctl_close(handle);
}
}
debug(
2, "device: \"%s\", name: \"%s\", type: \"%s\", id: \"%s\", CARD=%d,DEV=%u,SUBDEV=%u.",
alsa_out_dev, snd_pcm_info_get_name(local_alsa_info), device_types[device_type],
snd_pcm_info_get_id(local_alsa_info), snd_pcm_info_get_card(local_alsa_info),
snd_pcm_info_get_device(local_alsa_info), snd_pcm_info_get_subdevice(local_alsa_info));
// check what numbers of channels the device can provide...
unsigned int c;
// The Raspberry Pi built-in audio jack advertises 8-channel ability,
// but it is not actually capable of doing it.
// It can handle one- and two-channel stuff.
if (strcmp("bcm2835 Headphones", snd_pcm_info_get_name(local_alsa_info)) == 0) {
debug(1, "the output is to the Raspberry Pi built-in jack -- no more than two channels "
"will be used.");
for (c = 3; c <= 8; c++)
config.channel_set &=
~(1 << c); // the pi built-in jack DAC can't accommodate this number of channels
}
for (c = 1; c <= 8; c++) {
// if it's in the channel set -- either due to a setting in the configuration file or by
// default, check it...
if ((config.channel_set & (1 << c)) != 0) {
snd_pcm_hw_free(temporary_alsa_handle); // remove any previous configurations
ret = snd_pcm_hw_params_any(temporary_alsa_handle, local_alsa_params);
if (ret < 0)
debug(1, "Broken configuration for \"%s\": no configurations available: %s\n",
alsa_out_dev, snd_strerror(ret));
ret = snd_pcm_hw_params_set_rate_resample(temporary_alsa_handle, local_alsa_params, 0);
ret = snd_pcm_hw_params_test_channels(temporary_alsa_handle, local_alsa_params, c);
if (ret == 0) {
debug(3, "\"%s\" can handle %u channels.", alsa_out_dev, c);
} else {
// the device can't handle this number of channels
debug(3, "\"%s\" can not handle %u channels.", alsa_out_dev, c);
config.channel_set &=
~(1 << c); // the alsa device can't accommodate this number of channels
}
}
}
// check what speeds the device can handle
sps_rate_t r;
for (r = SPS_RATE_LOWEST; r <= SPS_RATE_HIGHEST; r++) {
// if it's in the rate set -- either due to a setting in the configuration file or by
// default, check it...
if ((config.rate_set & (1 << r)) != 0) {
snd_pcm_hw_free(temporary_alsa_handle); // remove any previous configurations
ret = snd_pcm_hw_params_any(temporary_alsa_handle, local_alsa_params);
if (ret < 0)
debug(1, "Broken configuration for \"%s\": no configurations available: %s\n",
alsa_out_dev, snd_strerror(ret));
ret = snd_pcm_hw_params_set_rate_resample(temporary_alsa_handle, local_alsa_params, 0);
ret = snd_pcm_hw_params_test_rate(temporary_alsa_handle, local_alsa_params,
sps_rate_actual_rate(r),
0); // 0 means exact rate only
if (ret == 0) {
debug(3, "\"%s\" can handle a rate of %u fps.", alsa_out_dev,
sps_rate_actual_rate(r));
} else {
debug(3, "\"%s\" can not handle a rate of %u fps.", alsa_out_dev,
sps_rate_actual_rate(r));
config.rate_set &= ~(1 << r); // the alsa device doesn't do this rate
}
}
}
// check what formats the device can handle
sps_format_t f;
for (f = SPS_FORMAT_LOWEST; f <= SPS_FORMAT_HIGHEST_NATIVE; f++) {
// if it's in the format set -- either due to a setting in the configuration file or by
// default, check it...
if ((config.format_set & (1 << f)) != 0) {
snd_pcm_hw_free(temporary_alsa_handle); // remove any previous configurations
ret = snd_pcm_hw_params_any(temporary_alsa_handle, local_alsa_params);
if (ret < 0)
debug(1, "Broken configuration for \"%s\": no configurations available: %s\n",
alsa_out_dev, snd_strerror(ret));
ret = snd_pcm_hw_params_set_rate_resample(temporary_alsa_handle, local_alsa_params, 0);
ret = snd_pcm_hw_params_test_format(temporary_alsa_handle, local_alsa_params,
fr[f].alsa_code);
if (ret == 0) {
debug(3, "\"%s\" can handle the %s format.", alsa_out_dev,
sps_format_description_string(f));
} else {
debug(3, "\"%s\" can not handle the %s format.", alsa_out_dev,
sps_format_description_string(f));
config.format_set &= ~(1 << f); // the alsa device doesn't do this format
}
}
}
// now we have the channels, rates and formats, but we need to check each combination
// set the permissible_configurations array (r/f/c) to EINVAL
for (r = SPS_RATE_LOWEST; r <= SPS_RATE_HIGHEST; r++)
for (f = SPS_FORMAT_LOWEST; f <= SPS_FORMAT_HIGHEST_NATIVE; f++)
for (c = 0; c <= 8; c++) {
permissible_configurations[r][f][c] = EINVAL;
}
// now check each combination of permitted rate/format/channel and see if it's really
// allowed
for (r = SPS_RATE_LOWEST; r <= SPS_RATE_HIGHEST; r++) {
if ((config.rate_set & (1 << r)) != 0) {
for (f = SPS_FORMAT_LOWEST; f <= SPS_FORMAT_HIGHEST_NATIVE; f++) {
if ((config.format_set & (1 << f)) != 0) {
for (c = 0; c <= 8; c++) {
if ((config.channel_set & (1 << c)) != 0) {
// debug(1, "check %u/%s/%u.", sps_rate_actual_rate(r),
// sps_format_description_string(f), c); note: only do the check if it's not a
// plug-in, i.e. not of type SND_PCM_TYPE_PLUG, or a If it is a plugin, this
// check may take way too long and will likely be unnecessary anyway. Similarly
// for a NULL or an IOPLUG device.
if ((device_type == SND_PCM_TYPE_PLUG) || (device_type == SND_PCM_TYPE_NULL) ||
(device_type == SND_PCM_TYPE_IOPLUG)) {
permissible_configurations[r][f][c] = 0;
} else {
snd_pcm_hw_free(temporary_alsa_handle); // remove any previous configurations
ret = snd_pcm_hw_params_any(temporary_alsa_handle, local_alsa_params);
if (ret == 0) {
ret = snd_pcm_hw_params_set_rate_resample(temporary_alsa_handle,
local_alsa_params, 0);
ret = snd_pcm_hw_params_test_channels(temporary_alsa_handle,
local_alsa_params, c);
if (ret == 0) {
ret = snd_pcm_hw_params_test_rate(
temporary_alsa_handle, local_alsa_params, sps_rate_actual_rate(r),
0); // 0 means exact rate only
if (ret == 0) {
ret = snd_pcm_hw_params_test_format(temporary_alsa_handle,
local_alsa_params, fr[f].alsa_code);
if (ret == 0) {
// debug(1, "passed: \"%s\", format: %s, rate: %u channels: %u.",
// alsa_out_dev, sps_format_description_string(f),
// sps_rate_actual_rate(r), c);
permissible_configurations[r][f][c] =
0; // i.e. no error, so remove the EINVAL
} else {
debug(1, "Can't set format %s for \"%s\": %s.",
sps_format_description_string(f), alsa_out_dev,
snd_strerror(ret));
}
} else {
debug(1, "Can't set rate of %u for \"%s\": %s.",
sps_rate_actual_rate(r), alsa_out_dev, snd_strerror(ret));
}
} else {
debug(1, "Can't set channel count of %u for \"%s\": %s.", c, alsa_out_dev,
snd_strerror(ret));
}
} else {
debug(1, "Broken configuration for \"%s\": %s.", alsa_out_dev,
snd_strerror(ret));
}
}
}
}
}
}
}
}
// close the device
snd_pcm_close(temporary_alsa_handle);
permissible_configuration_check_done = 1;
ret = 0; // all good here, even if the last ret was an error
}
}
pthread_cleanup_pop(1); // unlock the mutex
if (ret != 0) {
char errorstring[1024];
strerror_r(-ret, (char *)errorstring, sizeof(errorstring));
debug(1, "get_permissible_configuration_settings: error %d (\"%s\").", ret, errorstring);
}
int64_t hot = get_absolute_time_in_ns() - hto;
if (hot > 200000000)
debug(1,
"get_permissible_configuration_settings: permissible configurations check took %f ms.",
0.000001 * hot);
}
return ret;
}
static int precision_delay_and_status(snd_pcm_state_t *state, snd_pcm_sframes_t *delay,
yndk_type *using_update_timestamps);
static int standard_delay_and_status(snd_pcm_state_t *state, snd_pcm_sframes_t *delay,
yndk_type *using_update_timestamps);
// use this to allow the use of standard or precision delay calculations, with standard the, uh,
// standard.
int (*delay_and_status)(snd_pcm_state_t *state, snd_pcm_sframes_t *delay,
yndk_type *using_update_timestamps) = standard_delay_and_status;
// this will return true if the DAC can return precision delay information and false if not
// if it is not yet known, it will test the output device to find out
// note -- once it has done the test, it decides -- even if the delay comes back with
// "don't know", it will take that as a "No" and remember it.
// If you want it to check again, set precision_delay_available_status to YNDK_DONT_KNOW
// first.
static int precision_delay_available() {
if (precision_delay_available_status == YNDK_DONT_KNOW) {
// this is very crude -- if the device is a hardware device, then it's assumed the delay is
// precise
const char *output_device_name = snd_pcm_name(alsa_handle);
int is_a_real_hardware_device = 0;
if (output_device_name != NULL)
is_a_real_hardware_device = (strstr(output_device_name, "hw:") == output_device_name);
// The criteria as to whether precision delay is available
// is whether the device driver returns non-zero update timestamps
// If it does, and the device is a hardware device (i.e. its name begins with "hw:"),
// it is considered that precision delay is available. Otherwise, it's considered to be
// unavailable.
// To test, we play a silence buffer (fairly large to avoid underflow)
// and then we check the delay return. It will tell us if it
// was able to use the (non-zero) update timestamps
int frames_of_silence = 4410;
size_t size_of_silence_buffer =
frames_of_silence *
fr[FORMAT_FROM_ENCODED_FORMAT(current_encoded_output_format)].sample_size *
CHANNELS_FROM_ENCODED_FORMAT(current_encoded_output_format);
void *silence = malloc(size_of_silence_buffer);
if (silence == NULL) {
debug(1, "alsa: precision_delay_available -- failed to "
"allocate memory for a "
"silent frame buffer.");
} else {
pthread_cleanup_push(malloc_cleanup, &silence);
int use_dither = 0;
if ((alsa_mix_ctrl == NULL) && (config.ignore_volume_control == 0) &&
(config.airplay_volume != 0.0))
use_dither = 1;
dither_random_number_store =
generate_zero_frames(silence, frames_of_silence,
use_dither, // i.e. with dither
dither_random_number_store, current_encoded_output_format);
do_play(silence, frames_of_silence);
pthread_cleanup_pop(1);
// now we can get the delay, and we'll note if it uses update timestamps
yndk_type uses_update_timestamps;
snd_pcm_state_t state;
snd_pcm_sframes_t delay;
int ret = precision_delay_and_status(&state, &delay, &uses_update_timestamps);
// debug(3,"alsa: precision_delay_available asking for delay and status with a return status
// of %d, a delay of %ld and a uses_update_timestamps of %d.", ret, delay,
// uses_update_timestamps);
if (ret == 0) {
if ((uses_update_timestamps == YNDK_YES) && (is_a_real_hardware_device)) {
precision_delay_available_status = YNDK_YES;
debug(2, "alsa: precision delay timing is available.");
} else {
if ((uses_update_timestamps == YNDK_YES) && (!is_a_real_hardware_device)) {
debug(2, "alsa: precision delay timing is not available because it's not definitely a "
"hardware device.");
} else {
debug(2, "alsa: precision delay timing is not available.");
}
precision_delay_available_status = YNDK_NO;
}
}
}
}
return (precision_delay_available_status == YNDK_YES);
}
int alsa_characteristics_already_listed = 0;
snd_pcm_uframes_t period_size_requested, buffer_size_requested;
int set_period_size_request, set_buffer_size_request;
uint64_t frames_sent_for_playing;
// set to true if there has been a discontinuity between the last reported frames_sent_for_playing
// and the present reported frames_sent_for_playing
// Note that it will be set when the device is opened, as any previous figures for
// frames_sent_for_playing (which Shairport Sync might hold) would be invalid.
int frames_sent_break_occurred;
// if a device name ends in ",DEV=0", drop it. Then if it also begins with "CARD=", drop that too.
static void simplify_and_printf_device_name(char *device_name) {
if (strstr(device_name, ",DEV=0") == device_name + strlen(device_name) - strlen(",DEV=0")) {
char *shortened_device_name = str_replace(device_name, ",DEV=0", "");
char *simplified_device_name = str_replace(shortened_device_name, "CARD=", "");
printf(" \"%s\"\n", simplified_device_name);
free(simplified_device_name);
free(shortened_device_name);
} else {
printf(" \"%s\"\n", device_name);
}
}
static void help(void) {
printf(" -d output-device set the output device, default is \"default\".\n"
" -c mixer-control set the mixer control name, default is to use no mixer.\n"
" -m mixer-device set the mixer device, default is the output device.\n"
" -i mixer-index set the mixer index, default is 0.\n");
// look for devices with a name prefix of hw: or hdmi:
int card_number = -1;
snd_card_next(&card_number);
if (card_number < 0) {
printf(" no hardware output devices found.\n");
}
int at_least_one_device_found = 0;
while (card_number >= 0) {
void **hints;
char *hdmi_str = NULL;
char *hw_str = NULL;
if (snd_device_name_hint(card_number, "pcm", &hints) == 0) {
void **device_on_card_hints = hints;
while (*device_on_card_hints != NULL) {
char *device_on_card_name = snd_device_name_get_hint(*device_on_card_hints, "NAME");
if ((strstr(device_on_card_name, "hw:") == device_on_card_name) && (hw_str == NULL))
hw_str = strdup(device_on_card_name);
if ((strstr(device_on_card_name, "hdmi:") == device_on_card_name) && (hdmi_str == NULL))
hdmi_str = strdup(device_on_card_name);
free(device_on_card_name);
device_on_card_hints++;
}
snd_device_name_free_hint(hints);
if ((hdmi_str != NULL) || (hw_str != NULL)) {
if (at_least_one_device_found == 0) {
printf(" hardware output devices:\n");
at_least_one_device_found = 1;
}
}
if (hdmi_str != NULL) {
simplify_and_printf_device_name(hdmi_str);
} else if (hw_str != NULL) {
simplify_and_printf_device_name(hw_str);
}
if (hdmi_str != NULL)
free(hdmi_str);
if (hw_str != NULL)
free(hw_str);
}
snd_card_next(&card_number);
}
if (at_least_one_device_found == 0)
printf(" no hardware output devices found.\n");
}
void set_alsa_out_dev(char *dev) {
alsa_out_dev = dev;
if (hw_alsa_out_dev != NULL)
free(hw_alsa_out_dev);
hw_alsa_out_dev = str_replace(alsa_out_dev, "hdmi:", "hw:");
}
// assuming pthread cancellation is disabled
// returns zero of all is okay, a Unx error code if there's a problem
static int open_mixer() {
int response = 0;
if (alsa_mix_ctrl != NULL) {
debug(3, "Open Mixer");
snd_mixer_selem_id_alloca(&alsa_mix_sid);
snd_mixer_selem_id_set_index(alsa_mix_sid, alsa_mix_index);
snd_mixer_selem_id_set_name(alsa_mix_sid, alsa_mix_ctrl);
if ((response = snd_mixer_open(&alsa_mix_handle, 0)) < 0) {
debug(1, "Failed to open mixer");
} else {
debug(3, "Mixer device name is \"%s\".", alsa_mix_dev);
if ((response = snd_mixer_attach(alsa_mix_handle, alsa_mix_dev)) < 0) {
debug(1, "Failed to attach mixer");
} else {
if ((response = snd_mixer_selem_register(alsa_mix_handle, NULL, NULL)) < 0) {
debug(1, "Failed to register mixer element");
} else {
if ((response = snd_mixer_load(alsa_mix_handle)) < 0) {
debug(1, "Failed to load mixer element");
} else {
debug(3, "Mixer control is \"%s\",%d.", alsa_mix_ctrl, alsa_mix_index);
alsa_mix_elem = snd_mixer_find_selem(alsa_mix_handle, alsa_mix_sid);
if (!alsa_mix_elem) {
warn("failed to find mixer control \"%s\",%d.", alsa_mix_ctrl, alsa_mix_index);
response = -ENXIO; // don't let this be ENODEV!
}
}
}
}
}
}
return response;
}
// assuming pthread cancellation is disabled
static int close_mixer() {
int ret = 0;
if (alsa_mix_handle) {
ret = snd_mixer_close(alsa_mix_handle);
alsa_mix_handle = NULL;
}
return ret;
}
// assuming pthread cancellation is disabled
static int do_snd_mixer_selem_set_playback_dB_all(snd_mixer_elem_t *mix_elem, double vol) {
int response = 0;
if ((response = snd_mixer_selem_set_playback_dB_all(mix_elem, vol, 0)) != 0) {
debug(1, "Can't set playback volume accurately to %f dB.", vol);
if ((response = snd_mixer_selem_set_playback_dB_all(mix_elem, vol, -1)) != 0)
if ((response = snd_mixer_selem_set_playback_dB_all(mix_elem, vol, 1)) != 0)
debug(1, "Could not set playback dB volume on the mixer.");
}
return response;
}
// assuming pthread cancellation is disabled
static int actual_open_alsa_device() {
// the alsa mutex is already acquired when this is called
int result = 0;
if (current_encoded_output_format != 0) {
unsigned int rate = RATE_FROM_ENCODED_FORMAT(current_encoded_output_format);
sps_format_t format = (sps_format_t)FORMAT_FROM_ENCODED_FORMAT(current_encoded_output_format);
unsigned int channels = CHANNELS_FROM_ENCODED_FORMAT(current_encoded_output_format);
int ret, dir = 0;
// unsigned int actual_sample_rate; // this will be given the rate requested and will be given
// the actual rate snd_pcm_uframes_t frames = 441 * 10;
snd_pcm_uframes_t actual_buffer_length_in_frames;
snd_pcm_access_t access;
ret = snd_pcm_open(&alsa_handle, alsa_out_dev, SND_PCM_STREAM_PLAYBACK, 0);
// EHOSTDOWN seems to signify that it's a PipeWire pseudo device that can't be accessed by this
// user. So, try the first device ALSA device and log it.
if ((ret == -EHOSTDOWN) && (strcmp(alsa_out_dev, "default") == 0)) {
ret = snd_pcm_open(&alsa_handle, "hw:0", SND_PCM_STREAM_PLAYBACK, 0);
if ((ret == 0) || (ret == -EBUSY)) {
// being busy should be okay
inform("the default ALSA device is inaccessible -- \"hw:0\" used instead.");
set_alsa_out_dev("hw:0");
}
}
if (ret == 0) {
if (alsa_handle_status == -EBUSY)
warn("The output device \"%s\" is no longer busy and will be used by Shairport Sync.",
alsa_out_dev);
alsa_handle_status = ret; // all cool
} else {
alsa_handle = NULL; // to be sure to be sure
if (ret == -EBUSY) {
if (alsa_handle_status != -EBUSY)
warn("The output device \"%s\" is busy and can't be used by Shairport Sync at present.",
alsa_out_dev);
debug(2, "the alsa output_device \"%s\" is busy.", alsa_out_dev);
}
alsa_handle_status = ret;
frames_sent_break_occurred = 1;
return ret;
}
snd_pcm_hw_params_alloca(&alsa_params);
snd_pcm_sw_params_alloca(&alsa_swparams);
ret = snd_pcm_hw_params_any(alsa_handle, alsa_params);
if (ret < 0) {
die("audio_alsa: Broken configuration for device \"%s\": no configurations "
"available",
alsa_out_dev);
return ret;
}
if ((config.no_mmap == 0) &&
(snd_pcm_hw_params_set_access(alsa_handle, alsa_params, SND_PCM_ACCESS_MMAP_INTERLEAVED) >=
0)) {
if (output_method_signalled == 0) {
debug(3, "Output written using MMAP");
output_method_signalled = 1;
}
access = SND_PCM_ACCESS_MMAP_INTERLEAVED;
alsa_pcm_write = snd_pcm_mmap_writei;
} else {
if (output_method_signalled == 0) {
debug(3, "Output written with RW");
output_method_signalled = 1;
}
access = SND_PCM_ACCESS_RW_INTERLEAVED;
alsa_pcm_write = snd_pcm_writei;
}
ret = snd_pcm_hw_params_set_access(alsa_handle, alsa_params, access);
if (ret < 0) {
die("alsa: access type not available for device \"%s\": %s", alsa_out_dev, snd_strerror(ret));
return ret;
}
ret = snd_pcm_hw_params_set_channels(alsa_handle, alsa_params, channels);
if (ret < 0) {
die("alsa: %u channels not available for device \"%s\": %s", channels, alsa_out_dev,
snd_strerror(ret));
return ret;
}
snd_pcm_format_t sf = fr[format].alsa_code;
ret = snd_pcm_hw_params_set_format(alsa_handle, alsa_params, sf);
if (ret < 0) {
die("alsa: sample format %s not available for device \"%s\": %s",
sps_format_description_string(format), alsa_out_dev, snd_strerror(ret));
return ret;
}
// on some devices, it seems that setting the rate directly doesn't work.
dir = 0;
unsigned int actual_sample_rate = rate;
ret = snd_pcm_hw_params_set_rate_near(alsa_handle, alsa_params, &actual_sample_rate, &dir);
if ((ret < 0) || (actual_sample_rate != rate)) {
die("alsa: The frame rate of %i frames per second is not available for playback: %s", rate,
snd_strerror(ret));
return ret;
}
if (set_period_size_request != 0) {
debug(1, "Attempting to set the period size to %lu", period_size_requested);
ret = snd_pcm_hw_params_set_period_size_near(alsa_handle, alsa_params, &period_size_requested,
&dir);
if (ret < 0) {
warn("alsa: cannot set period size of %lu: %s", period_size_requested, snd_strerror(ret));
return ret;
} else {
snd_pcm_uframes_t actual_period_size;
snd_pcm_hw_params_get_period_size(alsa_params, &actual_period_size, &dir);
if (actual_period_size != period_size_requested)
inform("Actual period size set to a different value than requested. "
"Requested: %lu, actual "
"setting: %lu",
period_size_requested, actual_period_size);
}
}
if (set_buffer_size_request != 0) {
debug(1, "Attempting to set the buffer size to %lu", buffer_size_requested);
ret =
snd_pcm_hw_params_set_buffer_size_near(alsa_handle, alsa_params, &buffer_size_requested);
if (ret < 0) {
warn("alsa: cannot set buffer size of %lu: %s", buffer_size_requested, snd_strerror(ret));
return ret;
} else {
snd_pcm_uframes_t actual_buffer_size;
snd_pcm_hw_params_get_buffer_size(alsa_params, &actual_buffer_size);
if (actual_buffer_size != buffer_size_requested)
inform("Actual period size set to a different value than requested. "
"Requested: %lu, actual "
"setting: %lu",
buffer_size_requested, actual_buffer_size);
}
}
ret = snd_pcm_hw_params(alsa_handle, alsa_params);
if (ret < 0) {
die("alsa: Unable to set hw parameters for device \"%s\": %s.", alsa_out_dev,
snd_strerror(ret));
return ret;
}
// check parameters after attempting to set them
if (set_period_size_request != 0) {
snd_pcm_uframes_t actual_period_size;
snd_pcm_hw_params_get_period_size(alsa_params, &actual_period_size, &dir);
if (actual_period_size != period_size_requested)
inform("Actual period size set to a different value than requested. "
"Requested: %lu, actual "
"setting: %lu",
period_size_requested, actual_period_size);
}
if (set_buffer_size_request != 0) {
snd_pcm_uframes_t actual_buffer_size;
snd_pcm_hw_params_get_buffer_size(alsa_params, &actual_buffer_size);
if (actual_buffer_size != buffer_size_requested)
inform("Actual period size set to a different value than requested. "
"Requested: %lu, actual "
"setting: %lu",
buffer_size_requested, actual_buffer_size);
}
use_monotonic_clock = snd_pcm_hw_params_is_monotonic(alsa_params);
ret = snd_pcm_hw_params_get_buffer_size(alsa_params, &actual_buffer_length_in_frames);
if (ret < 0) {
warn("alsa: unable to get hw buffer length for device \"%s\": %s.", alsa_out_dev,
snd_strerror(ret));
return ret;
}
ret = snd_pcm_sw_params_current(alsa_handle, alsa_swparams);
if (ret < 0) {
warn("alsa: unable to get current sw parameters for device \"%s\": "
"%s.",
alsa_out_dev, snd_strerror(ret));
return ret;
}
ret = snd_pcm_sw_params_set_tstamp_mode(alsa_handle, alsa_swparams, SND_PCM_TSTAMP_ENABLE);
if (ret < 0) {
warn("alsa: can't enable timestamp mode of device: \"%s\": %s.", alsa_out_dev,
snd_strerror(ret));
return ret;
}
/* write the sw parameters */
ret = snd_pcm_sw_params(alsa_handle, alsa_swparams);
if (ret < 0) {
warn("alsa: unable to set software parameters of device: \"%s\": %s.", alsa_out_dev,
snd_strerror(ret));
return ret;
}
ret = snd_pcm_prepare(alsa_handle);
if (ret < 0) {
warn("alsa: unable to prepare the device: \"%s\": %s.", alsa_out_dev, snd_strerror(ret));
return ret;
}
if (config.use_precision_timing == YNA_YES)
delay_and_status = precision_delay_and_status;
else if (config.use_precision_timing == YNA_AUTO) {
if (precision_delay_available()) {
delay_and_status = precision_delay_and_status;
debug(2, "alsa: precision timing selected for \"auto\" mode");
}
}
if (alsa_characteristics_already_listed == 0) {
alsa_characteristics_already_listed = 1;
int log_level = 2; // the level at which debug information should be output
// int rc;
snd_pcm_access_t access_type;
snd_pcm_format_t format_type;
snd_pcm_subformat_t subformat_type;
// unsigned int val, val2;
unsigned int uval, uval2;
int sval;
int direction;
snd_pcm_uframes_t frames;
debug(log_level, "PCM handle name = '%s'", snd_pcm_name(alsa_handle));
debug(log_level, "alsa device parameters:");
snd_pcm_hw_params_get_access(alsa_params, &access_type);
debug(log_level, " access type = %s", snd_pcm_access_name(access_type));
snd_pcm_hw_params_get_format(alsa_params, &format_type);
debug(log_level, " format = '%s' (%s)", snd_pcm_format_name(format_type),
snd_pcm_format_description(format_type));
snd_pcm_hw_params_get_subformat(alsa_params, &subformat_type);
debug(log_level, " subformat = '%s' (%s)", snd_pcm_subformat_name(subformat_type),
snd_pcm_subformat_description(subformat_type));
snd_pcm_hw_params_get_channels(alsa_params, &uval);
debug(log_level, " number of channels = %u", uval);
sval = snd_pcm_hw_params_get_sbits(alsa_params);
debug(log_level, " number of significant bits = %d", sval);
snd_pcm_hw_params_get_rate(alsa_params, &uval, &direction);
switch (direction) {
case -1:
debug(log_level, " rate = %u frames per second (<).", uval);
break;
case 0:
debug(log_level, " rate = %u frames per second (precisely).", uval);
break;
case 1:
debug(log_level, " rate = %u frames per second (>).", uval);
break;
}
if ((snd_pcm_hw_params_get_rate_numden(alsa_params, &uval, &uval2) == 0) && (uval2 != 0))
// watch for a divide by zero too!
debug(log_level, " precise (rational) rate = %.3f frames per second (i.e. %u/%u).", (1.0 * uval) / uval2, uval,
uval2);
else
debug(log_level, " precise (rational) rate information unavailable.");
snd_pcm_hw_params_get_period_time(alsa_params, &uval, &direction);
switch (direction) {
case -1:
debug(log_level, " period_time = %u us (<).", uval);
break;
case 0:
debug(log_level, " period_time = %u us (precisely).", uval);
break;
case 1:
debug(log_level, " period_time = %u us (>).", uval);
break;
}
snd_pcm_hw_params_get_period_size(alsa_params, &frames, &direction);
switch (direction) {
case -1:
debug(log_level, " period_size = %lu frames (<).", frames);
break;
case 0:
debug(log_level, " period_size = %lu frames (precisely).", frames);
break;
case 1:
debug(log_level, " period_size = %lu frames (>).", frames);
break;
}
snd_pcm_hw_params_get_buffer_time(alsa_params, &uval, &direction);
switch (direction) {
case -1:
debug(log_level, " buffer_time = %u us (<).", uval);
break;
case 0:
debug(log_level, " buffer_time = %u us (precisely).", uval);
break;
case 1:
debug(log_level, " buffer_time = %u us (>).", uval);
break;
}
snd_pcm_hw_params_get_buffer_size(alsa_params, &frames);
switch (direction) {
case -1:
debug(log_level, " buffer_size = %lu frames (<).", frames);
break;
case 0:
debug(log_level, " buffer_size = %lu frames (precisely).", frames);
break;
case 1:
debug(log_level, " buffer_size = %lu frames (>).", frames);
break;
}
snd_pcm_hw_params_get_periods(alsa_params, &uval, &direction);
switch (direction) {
case -1:
debug(log_level, " periods_per_buffer = %u (<).", uval);
break;
case 0:
debug(log_level, " periods_per_buffer = %u (precisely).", uval);
break;
case 1:
debug(log_level, " periods_per_buffer = %u (>).", uval);
break;
}
}
stall_monitor_new_frame_count = 0;
stall_monitor_new_frame_count_time = 0;
} else {
debug(1, "no current_alsa_configuration");
result = -1;
}
return result;
}
static int open_alsa_device() {
int result;
int oldState;
pthread_setcancelstate(PTHREAD_CANCEL_DISABLE, &oldState); // make this un-cancellable
result = actual_open_alsa_device();
if (result != 0)
debug(1, "Error in open_alsa_device: %d.", result);
pthread_setcancelstate(oldState, NULL);
return result;
}
static int prepare_mixer() {
int response = 0;
// do any alsa device initialisation (general case)
// at present, this is only needed if a hardware mixer is being used
// if there's a hardware mixer, it needs to be initialised before use
if (alsa_mix_ctrl == NULL) {
audio_alsa.volume = NULL;
audio_alsa.mute = NULL;
output_parameters.volume_range = NULL; // until we know, we won't offer a volume range
} else {
debug(2, "alsa: hardware mixer prepare");
int oldState;
pthread_setcancelstate(PTHREAD_CANCEL_DISABLE, &oldState); // make this un-cancellable
if (alsa_mix_dev == NULL)
alsa_mix_dev = hw_alsa_out_dev;
// Now, start trying to initialise the alsa device with the settings
// obtained
pthread_cleanup_debug_mutex_lock(&alsa_mixer_mutex, 1000, 1);
if (open_mixer() == 0) {
if (snd_mixer_selem_get_playback_volume_range(alsa_mix_elem, &alsa_mix_minv, &alsa_mix_maxv) <
0) {
debug(1, "Can't read mixer's [linear] min and max volumes.");
} else {
if (snd_mixer_selem_get_playback_dB_range(alsa_mix_elem, &alsa_mix_mindb,
&alsa_mix_maxdb) == 0) {
if (alsa_mix_mindb == SND_CTL_TLV_DB_GAIN_MUTE) {
// For instance, the Raspberry Pi does this
debug(2, "Lowest dB value is a mute");
mixer_volume_setting_gives_mute = 1;
alsa_mix_mute = SND_CTL_TLV_DB_GAIN_MUTE; // this may not be
// necessary -- it's
// always
// going to be SND_CTL_TLV_DB_GAIN_MUTE, right?
// debug(1, "Try minimum volume + 1 as lowest true attenuation
// value");
// now we need to find a lowest dB value that isn't a mute
// so we'll work from alsa_mix_minv upwards until we get a db value
// that is not SND_CTL_TLV_DB_GAIN_MUTE
long cv;
for (cv = alsa_mix_minv;
cv <= alsa_mix_maxv && (alsa_mix_mindb == SND_CTL_TLV_DB_GAIN_MUTE); cv++) {
if (snd_mixer_selem_ask_playback_vol_dB(alsa_mix_elem, cv, &alsa_mix_mindb) != 0)
debug(1, "Can't get dB value corresponding to a minimum volume "
"+ 1.");
}
}
debug(3, "Hardware mixer has dB volume from %f to %f.", (1.0 * alsa_mix_mindb) / 100.0,
(1.0 * alsa_mix_maxdb) / 100.0);
audio_alsa.volume = &volume; // insert the volume function now we
// know it can do dB stuff
volume_range.minimum_volume_dB = alsa_mix_mindb;
volume_range.maximum_volume_dB = alsa_mix_maxdb;
output_parameters.volume_range = &volume_range;
} else {
// use the linear scale and do the db conversion ourselves
warn("The hardware mixer specified -- \"%s\" -- does not have "
"a dB volume scale.",
alsa_mix_ctrl);
if ((response = snd_ctl_open(&ctl, alsa_mix_dev, 0)) < 0) {
warn("Cannot open control \"%s\"", alsa_mix_dev);
}
if ((response = snd_ctl_elem_id_malloc(&elem_id)) < 0) {
debug(1, "Cannot allocate memory for control \"%s\"", alsa_mix_dev);
elem_id = NULL;
} else {
snd_ctl_elem_id_set_interface(elem_id, SND_CTL_ELEM_IFACE_MIXER);
snd_ctl_elem_id_set_name(elem_id, alsa_mix_ctrl);
if (snd_ctl_get_dB_range(ctl, elem_id, &alsa_mix_mindb, &alsa_mix_maxdb) == 0) {
debug(1,
"alsa: hardware mixer \"%s\" selected, with dB volume "
"from %f to %f.",
alsa_mix_ctrl, (1.0 * alsa_mix_mindb) / 100.0, (1.0 * alsa_mix_maxdb) / 100.0);
has_softvol = 1;
audio_alsa.volume = &volume; // insert the volume function now we
// know it can do dB stuff
volume_range.minimum_volume_dB = alsa_mix_mindb;
volume_range.maximum_volume_dB = alsa_mix_maxdb;
output_parameters.volume_range = &volume_range;
} else {
debug(1, "Cannot get the dB range from the volume control \"%s\"", alsa_mix_ctrl);
}
}
}
}
if (((config.alsa_use_hardware_mute == 1) &&
(snd_mixer_selem_has_playback_switch(alsa_mix_elem))) ||
mixer_volume_setting_gives_mute) {
audio_alsa.mute = &mute; // insert the mute function now we know it
// can do muting stuff
// debug(1, "Has mixer and mute ability we will use.");
} else {
// debug(1, "Has mixer but not using hardware mute.");
}
if (response == 0)
response = close_mixer();
}
debug_mutex_unlock(&alsa_mixer_mutex, 3); // release the mutex
pthread_cleanup_pop(0);
pthread_setcancelstate(oldState, NULL);
}
return response;
}
static int alsa_device_init() { return prepare_mixer(); }
static void
snd_error_quiet(__attribute__((unused)) const char *file, __attribute__((unused)) int line,
__attribute__((unused)) const char *func, __attribute__((unused)) int err,
__attribute__((unused)) const char *fmt, __attribute__((unused)) va_list arg) {
// return NULL;
}
static int init(int argc, char **argv) {
snd_lib_error_set_handler((snd_lib_error_handler_t)snd_error_quiet);
current_encoded_output_format = 0;
// for debugging
snd_output_stdio_attach(&output, stdout, 0);
// debug(2,"audio_alsa init called.");
// int response = 0; // this will be what we return to the caller.
alsa_device_initialised = 0;
const char *str;
int value;
// double dvalue;
// set up default values first
config.no_mmap = 1; // some devices don't implement this properly and crash with data is dropped
alsa_backend_state = abm_disconnected; // startup state
debug(2, "alsa: init() -- alsa_backend_state => abm_disconnected.");
set_period_size_request = 0;
set_buffer_size_request = 0;
config.alsa_use_hardware_mute = 0; // don't use it by default
config.audio_backend_latency_offset = 0;
config.audio_backend_buffer_desired_length = 0.200;
config.audio_backend_buffer_interpolation_threshold_in_seconds =
0.060; // below this, basic interpolation will be used to save time.
config.alsa_maximum_stall_time = 0.200; // 200 milliseconds -- if it takes longer, it's a problem
config.disable_standby_mode_silence_threshold =
0.040; // start sending silent frames if the delay goes below this time
// on slower single-core machines, it doesn't make sense to make this much less than about 40 ms,
// as, whatever the setting, the scheduler may let it sleep for much longer -- up to 80
// milliseconds.
config.disable_standby_mode_silence_scan_interval = 0.030; // check silence threshold this often
config.disable_standby_mode = disable_standby_off;
config.keep_dac_busy = 0;
config.use_precision_timing = YNA_NO;
disable_standby_mode_default_format = SPS_FORMAT_S32_LE;
#ifdef CONFIG_AIRPLAY_2
disable_standby_mode_default_rate = 48000;
#else
disable_standby_mode_default_rate = 44100;
#endif
disable_standby_mode_default_channels = 2;
// get settings from settings file first, allow them to be overridden by
// command line options
// get settings from settings file, passing in defaults for format_set, rate_set and channel_set
// Note, these options may be in the "general" stanza or the named stanza
#ifdef CONFIG_FFMPEG
parse_audio_options("alsa", SPS_FORMAT_SET, SPS_RATE_SET, SPS_CHANNEL_SET);
#else
parse_audio_options("alsa", SPS_FORMAT_NON_FFMPEG_SET, SPS_RATE_NON_FFMPEG_SET,
SPS_CHANNNEL_NON_FFMPEG_SET);
#endif
if (config.cfg != NULL) {
double dvalue;
/* Get the Output Device Name. */
if (config_lookup_non_empty_string(config.cfg, "alsa.output_device", &str)) {
alsa_out_dev = (char *)str;
}
/* Get the Mixer Type setting. */
if (config_lookup_non_empty_string(config.cfg, "alsa.mixer_type", &str)) {
inform("The alsa mixer_type setting is deprecated and has been ignored. "
"FYI, using the \"mixer_control_name\" setting automatically "
"chooses a hardware mixer.");
}
/* Get the Mixer Device Name. */
if (config_lookup_non_empty_string(config.cfg, "alsa.mixer_device", &str)) {
alsa_mix_dev = (char *)str;
}
/* Get the Mixer Control Name. */
if (config_lookup_non_empty_string(config.cfg, "alsa.mixer_control_name", &str)) {
alsa_mix_ctrl = (char *)str;
}
// Get the Mixer Control Index
if (config_lookup_int(config.cfg, "alsa.mixer_control_index", &value)) {
alsa_mix_index = value;
}
/* Get the disable_synchronization setting. */
if (config_lookup_string(config.cfg, "alsa.disable_synchronization", &str)) {
if (strcasecmp(str, "no") == 0)
config.no_sync = 0;
else if (strcasecmp(str, "yes") == 0)
config.no_sync = 1;
else {
warn("Invalid disable_synchronization option choice \"%s\". It should "
"be \"yes\" or "
"\"no\". It is set to \"no\".", str);
config.no_sync = 0;
}
}
/* Get the mute_using_playback_switch setting. */
if (config_lookup_string(config.cfg, "alsa.mute_using_playback_switch", &str)) {
inform("The alsa \"mute_using_playback_switch\" setting is deprecated. "
"Please use the \"use_hardware_mute_if_available\" setting instead.");
if (strcasecmp(str, "no") == 0)
config.alsa_use_hardware_mute = 0;
else if (strcasecmp(str, "yes") == 0)
config.alsa_use_hardware_mute = 1;
else {
warn("Invalid mute_using_playback_switch option choice \"%s\". It "
"should be \"yes\" or "
"\"no\". It is set to \"no\".", str);
config.alsa_use_hardware_mute = 0;
}
}
/* Get the use_hardware_mute_if_available setting. */
if (config_lookup_string(config.cfg, "alsa.use_hardware_mute_if_available", &str)) {
if (strcasecmp(str, "no") == 0)
config.alsa_use_hardware_mute = 0;
else if (strcasecmp(str, "yes") == 0)
config.alsa_use_hardware_mute = 1;
else {
warn("Invalid use_hardware_mute_if_available option choice \"%s\". It "
"should be \"yes\" or "
"\"no\". It is set to \"no\".", str);
config.alsa_use_hardware_mute = 0;
}
}
/* Get the use_mmap_if_available setting. */
if (config_lookup_string(config.cfg, "alsa.use_mmap_if_available", &str)) {
if (strcasecmp(str, "no") == 0)
config.no_mmap = 1;
else if (strcasecmp(str, "yes") == 0)
config.no_mmap = 0;
else {
warn("Invalid use_mmap_if_available option choice \"%s\". It should be "
"\"yes\" or \"no\". "
"It remains set to \"yes\".", str);
config.no_mmap = 0;
}
}
/* Get the optional period size value */
if (config_lookup_int(config.cfg, "alsa.period_size", &value)) {
set_period_size_request = 1;
debug(1, "Value read for period size is %d.", value);
if (value < 0) {
warn("Invalid alsa period size setting \"%d\". It "
"must be greater than 0. No setting is made.",
value);
set_period_size_request = 0;
} else {
period_size_requested = value;
}
}
/* Get the optional buffer size value */
if (config_lookup_int(config.cfg, "alsa.buffer_size", &value)) {
set_buffer_size_request = 1;
debug(1, "Value read for buffer size is %d.", value);
if (value < 0) {
warn("Invalid alsa buffer size setting \"%d\". It "
"must be greater than 0. No setting is made.",
value);
set_buffer_size_request = 0;
} else {
buffer_size_requested = value;
}
}
/* Get the optional alsa_maximum_stall_time setting. */
if (config_lookup_float(config.cfg, "alsa.maximum_stall_time", &dvalue)) {
if (dvalue < 0.0) {
warn("Invalid alsa maximum write time setting \"%f\". It "
"must be greater than 0. Default is \"%f\". No setting is made.",
dvalue, config.alsa_maximum_stall_time);
} else {
config.alsa_maximum_stall_time = dvalue;
}
}
/* Get the optional disable_standby_mode_silence_threshold setting. */
if (config_lookup_float(config.cfg, "alsa.disable_standby_mode_silence_threshold", &dvalue)) {
if (dvalue < 0.0) {
warn("Invalid alsa disable_standby_mode_silence_threshold setting \"%f\". It "
"must be greater than 0. Default is \"%f\". No setting is made.",
dvalue, config.disable_standby_mode_silence_threshold);
} else {
config.disable_standby_mode_silence_threshold = dvalue;
}
}
/* Get the optional disable_standby_mode_silence_scan_interval setting. */
if (config_lookup_float(config.cfg, "alsa.disable_standby_mode_silence_scan_interval",
&dvalue)) {
if (dvalue < 0.0) {
warn("Invalid alsa disable_standby_mode_silence_scan_interval setting \"%f\". It "
"must be greater than 0. Default is \"%f\". No setting is made.",
dvalue, config.disable_standby_mode_silence_scan_interval);
} else {
config.disable_standby_mode_silence_scan_interval = dvalue;
}
}
/* Get the optional disable_standby_mode setting. */
if (config_lookup_string(config.cfg, "alsa.disable_standby_mode", &str)) {
if ((strcasecmp(str, "no") == 0) || (strcasecmp(str, "off") == 0) ||
(strcasecmp(str, "never") == 0))
config.disable_standby_mode = disable_standby_off;
else if ((strcasecmp(str, "yes") == 0) || (strcasecmp(str, "on") == 0) ||
(strcasecmp(str, "always") == 0)) {
config.disable_standby_mode = disable_standby_always;
config.keep_dac_busy = 1;
} else if (strcasecmp(str, "auto") == 0)
config.disable_standby_mode = disable_standby_auto;
else {
warn("Invalid disable_standby_mode option choice \"%s\". It should be "
"\"always\", \"auto\" or \"never\". "
"It remains set to \"never\".",
str);
}
}
/* Get the optional disable_standby_mode_default_rate. */
if (config_lookup_int(config.cfg, "alsa.disable_standby_mode_default_rate", &value)) {
if (value < 0) {
warn("Invalid alsa disable_standby_mode_default_rate setting %d. It "
"must be greater than 0. Default is %d. No setting is made.",
value, disable_standby_mode_default_rate);
} else {
disable_standby_mode_default_rate = value;
}
}
/* Get the optional disable_standby_mode_default_channels. */
if (config_lookup_int(config.cfg, "alsa.disable_standby_mode_default_channels", &value)) {
if (value < 0) {
warn("Invalid alsa disable_standby_mode_default_channels setting %d. It "
"must be greater than 0. Default is %d. No setting is made.",
value, disable_standby_mode_default_channels);
} else {
disable_standby_mode_default_channels = value;
}
}
if (config_lookup_string(config.cfg, "alsa.use_precision_timing", &str)) {
if ((strcasecmp(str, "no") == 0) || (strcasecmp(str, "off") == 0) ||
(strcasecmp(str, "never") == 0))
config.use_precision_timing = YNA_NO;
else if ((strcasecmp(str, "yes") == 0) || (strcasecmp(str, "on") == 0) ||
(strcasecmp(str, "always") == 0)) {
config.use_precision_timing = YNA_YES;
config.keep_dac_busy = 1;
} else if (strcasecmp(str, "auto") == 0)
config.use_precision_timing = YNA_AUTO;
else {
warn("Invalid use_precision_timing option choice \"%s\". It should be "
"\"yes\", \"auto\" or \"no\". "
"It remains set to \"%s\".", str,
config.use_precision_timing == YNA_NO ? "no"
: config.use_precision_timing == YNA_AUTO ? "auto"
: "yes");
}
inform("Note: the \"alsa\" setting \"use_precision_timing\" is deprecated and will be "
"removed in a future update.");
}
}
optind = 1; // optind=0 is equivalent to optind=1 plus special behaviour
argv--; // so we shift the arguments to satisfy getopt()
argc++;
// some platforms apparently require optreset = 1; - which?
int opt;
while ((opt = getopt(argc, argv, "d:t:m:c:i:")) > 0) {
switch (opt) {
case 'd':
alsa_out_dev = optarg;
break;
case 't':
inform("The alsa backend -t option is deprecated and has been ignored. "
"FYI, using the -c option automatically chooses a hardware "
"mixer.");
break;
case 'm':
alsa_mix_dev = optarg;
break;
case 'c':
alsa_mix_ctrl = optarg;
break;
case 'i':
alsa_mix_index = strtol(optarg, NULL, 10);
break;
default:
warn("Invalid audio option \"-%c\" specified -- ignored.", opt);
help();
}
}
if (optind < argc) {
warn("Invalid audio argument: \"%s\" -- ignored", argv[optind]);
}
debug(2, "alsa: output device name is \"%s\".", alsa_out_dev);
// now, we need a version of the alsa_out_dev that substitutes "hw:" for "hdmi" if it's
// there. It seems hw:1 would be a valid devcie name where hdmi:1 would not
if (alsa_out_dev != NULL)
hw_alsa_out_dev = str_replace(alsa_out_dev, "hdmi:", "hw:");
debug(2, "alsa: disable_standby_mode is \"%s\".",
config.disable_standby_mode == disable_standby_off ? "never"
: config.disable_standby_mode == disable_standby_always ? "always"
: "auto");
debug(2, "alsa: disable_standby_mode_silence_threshold is %f seconds.",
config.disable_standby_mode_silence_threshold);
debug(2, "alsa: disable_standby_mode_silence_scan_interval is %f seconds.",
config.disable_standby_mode_silence_scan_interval);
stall_monitor_error_threshold =
(uint64_t)(config.alsa_maximum_stall_time * 1000000000); // stall time max to nanoseconds;
// so, now, if the option to keep the DAC running has been selected, start a
// thread to monitor the
// length of the queue
// if the queue gets too short, stuff it with silence
return named_pthread_create_with_priority(&alsa_buffer_monitor_thread, 4,
&alsa_buffer_monitor_thread_code, NULL, "alsa_buf_mon");
return 0;
}
static int check_configuration(unsigned int channels, unsigned int rate, unsigned int format) {
// we know that the format/rate/channel count are legitimate but the combination
// may not be permitted.
// now see if the individual formats, rates and channel count are permissible
sps_rate_t r = SPS_RATE_LOWEST;
int found = 0;
// we know the rate is there, we just have to find it.
while ((r <= SPS_RATE_HIGHEST) && (found == 0)) {
if ((sps_rate_actual_rate(r) == rate) && ((config.rate_set & (1 << r)) != 0))
found = 1;
else
r++;
}
int response = permissible_configurations[r][format][channels];
if (response != 0)
debug(3, "check %u/%s/%u returns %d.", rate, sps_format_description_string(format), channels,
response);
return response;
}
/*
static int check_configuration(unsigned int channels, unsigned int rate, unsigned int format) {
int response = response = check_settings(format, rate, channels);
debug(3, "alsa: configuration: %u/%s/%u %s.", rate, sps_format_description_string(format),
channels, response == 0 ? "is okay" : "can not be configured");
return response;
}
*/
static char *get_channel_map_str() {
if (alsa_handle != NULL) {
snd_pcm_chmap_t *channel_map = snd_pcm_get_chmap(alsa_handle);
if (channel_map) {
int j, k;
// check for duplicates and replace subsequent duplicates with
// SND_CHMAP_UNKNOWN
for (j = 0; j < (int)channel_map->channels; j++) {
for (k = 0; k < j; k++) {
if ((channel_map->pos[k] != SND_CHMAP_UNKNOWN) &&
(channel_map->pos[k] == channel_map->pos[j])) {
debug(3,
"alsa: There is an error in the built-in %u channel map of the "
"output device:"
" channel %d has the same name as channel "
"%d (\"%s\"). Both names have been changed to \"UNKNOWN\".",
channel_map->channels, j, k, snd_pcm_chmap_name(channel_map->pos[k]));
channel_map->pos[j] = SND_CHMAP_UNKNOWN;
channel_map->pos[k] = SND_CHMAP_UNKNOWN;
}
}
}
unsigned int i;
for (i = 0; i < channel_map->channels; i++) {
debug(3, "channel %d is %d, name: \"%s\", long name: \"%s\".", i, channel_map->pos[i],
snd_pcm_chmap_name(channel_map->pos[i]),
snd_pcm_chmap_long_name(channel_map->pos[i]));
}
if (snd_pcm_chmap_print(channel_map, sizeof(public_channel_map), public_channel_map) < 0)
public_channel_map[0] = '\0'; // if there's any problem
debug(3,
"channel count: %d, channel name list: "
"\"%s\".",
channel_map->channels, public_channel_map);
free(channel_map);
} else {
debug(2, "no channel map -- if it's two-channel, assume standard stereo.");
if (CHANNELS_FROM_ENCODED_FORMAT(current_encoded_output_format) == 2) {
// if it's a two-channel configuration, assume it's stereo and return
// a standard mapping
snprintf(public_channel_map, sizeof(public_channel_map) - 1, "FL FR");
}
}
}
return public_channel_map;
}
static int configure(int32_t requested_encoded_format, char **channel_map) {
int response = 0;
int oldState;
pthread_setcancelstate(PTHREAD_CANCEL_DISABLE, &oldState); // make this un-cancellable
pthread_cleanup_debug_mutex_lock(&alsa_mutex, 200000, 0);
if (current_encoded_output_format != requested_encoded_format) {
if (current_encoded_output_format == 0)
debug(2, "alsa: setting output configuration to %s.",
short_format_description(requested_encoded_format));
else
// note -- can't use short_format_description twice in one call because it returns the same
// string buffer each time
debug(3, "alsa: changing output configuration to %s.",
short_format_description(requested_encoded_format));
do_close();
current_encoded_output_format = requested_encoded_format;
response = do_open();
}
if ((response == 0) && (channel_map != NULL)) {
*channel_map = get_channel_map_str();
}
debug_mutex_unlock(&alsa_mutex, 0);
pthread_cleanup_pop(0);
pthread_setcancelstate(oldState, NULL);
if (response != 0)
debug(1, "alsa: could not open the output device with configuration %s",
short_format_description(requested_encoded_format));
return response;
}
static void deinit(void) {
int oldState;
pthread_setcancelstate(PTHREAD_CANCEL_DISABLE, &oldState); // make this un-cancellable
debug(2, "audio_alsa deinit called.");
pthread_cleanup_debug_mutex_lock(&alsa_mutex, 10000, 1);
if (alsa_handle != NULL) {
debug(3, "alsa: closing the output device.");
do_close();
} else {
debug(3, "alsa: output device already closed.");
}
pthread_cleanup_pop(1); // release the mutex
debug(2, "Cancel buffer monitor thread.");
pthread_cancel(alsa_buffer_monitor_thread);
debug(2, "Join buffer monitor thread.");
pthread_join(alsa_buffer_monitor_thread, NULL);
debug(2, "Joined buffer monitor thread.");
pthread_setcancelstate(oldState, NULL);
if (hw_alsa_out_dev != NULL)
free(hw_alsa_out_dev);
}
static int prepare() { return get_permissible_configuration_settings(); }
static int set_mute_state() {
int response = 1; // some problem expected, e.g. no mixer or not allowed to use it or disconnected
int oldState;
pthread_setcancelstate(PTHREAD_CANCEL_DISABLE, &oldState); // make this un-cancellable
pthread_cleanup_debug_mutex_lock(&alsa_mixer_mutex, 10000, 0);
if ((alsa_backend_state != abm_disconnected) && (config.alsa_use_hardware_mute == 1) &&
(open_mixer() == 0)) {
response = 0; // okay if actually using the mute facility
debug(2, "alsa: actually set_mute_state");
int mute = 0;
if ((mute_requested_externally != 0) || (mute_requested_internally != 0))
mute = 1;
if (mute == 1) {
debug(2, "alsa: hardware mute switched on");
if (snd_mixer_selem_has_playback_switch(alsa_mix_elem))
snd_mixer_selem_set_playback_switch_all(alsa_mix_elem, 0);
else {
volume_based_mute_is_active = 1;
do_snd_mixer_selem_set_playback_dB_all(alsa_mix_elem, alsa_mix_mute);
}
} else {
debug(2, "alsa: hardware mute switched off");
if (snd_mixer_selem_has_playback_switch(alsa_mix_elem))
snd_mixer_selem_set_playback_switch_all(alsa_mix_elem, 1);
else {
volume_based_mute_is_active = 0;
do_snd_mixer_selem_set_playback_dB_all(alsa_mix_elem, set_volume);
}
}
close_mixer();
}
debug_mutex_unlock(&alsa_mixer_mutex, 3); // release the mutex
pthread_cleanup_pop(0); // release the mutex
pthread_setcancelstate(oldState, NULL);
return response;
}
static output_parameters_t *parameters() { return &output_parameters; }
static void start(__attribute__((unused)) int i_sample_rate,
__attribute__((unused)) int i_sample_format) {
if (alsa_device_initialised == 0) {
debug(2, "alsa: start() calling alsa_device_init.");
alsa_device_init();
alsa_device_initialised = 1;
}
}
static int standard_delay_and_status(snd_pcm_state_t *state, snd_pcm_sframes_t *delay,
yndk_type *using_update_timestamps) {
int ret = alsa_handle_status;
if (using_update_timestamps)
*using_update_timestamps = YNDK_NO;
snd_pcm_state_t state_temp = SND_PCM_STATE_DISCONNECTED;
snd_pcm_sframes_t delay_temp = 0;
if (alsa_handle != NULL) {
state_temp = snd_pcm_state(alsa_handle);
if ((state_temp == SND_PCM_STATE_RUNNING) || (state_temp == SND_PCM_STATE_DRAINING)) {
ret = snd_pcm_delay(alsa_handle, &delay_temp);
} else {
// not running, thus no delay information, thus can't check for frame
// rates
// frame_index = 0; // we'll be starting over...
// measurement_data_is_valid = 0;
// delay_temp = 0;
ret = 0;
}
}
if (delay != NULL)
*delay = delay_temp;
if (state != NULL)
*state = state_temp;
return ret;
}
static int precision_delay_and_status(snd_pcm_state_t *state, snd_pcm_sframes_t *delay,
yndk_type *using_update_timestamps) {
snd_pcm_state_t state_temp = SND_PCM_STATE_DISCONNECTED;
snd_pcm_sframes_t delay_temp = 0;
if (using_update_timestamps)
*using_update_timestamps = YNDK_DONT_KNOW;
int ret = alsa_handle_status;
snd_pcm_status_t *alsa_snd_pcm_status;
snd_pcm_status_alloca(&alsa_snd_pcm_status);
struct timespec tn; // time now
snd_htimestamp_t update_timestamp; // actually a struct timespec
if (alsa_handle != NULL) {
ret = snd_pcm_status(alsa_handle, alsa_snd_pcm_status);
if (ret == 0) {
snd_pcm_status_get_htstamp(alsa_snd_pcm_status, &update_timestamp);
/*
// must be 1.1 or later to use snd_pcm_status_get_driver_htstamp
#if SND_LIB_MINOR != 0
snd_htimestamp_t driver_htstamp;
snd_pcm_status_get_driver_htstamp(alsa_snd_pcm_status, &driver_htstamp);
uint64_t driver_htstamp_ns = driver_htstamp.tv_sec;
driver_htstamp_ns = driver_htstamp_ns * 1000000000;
driver_htstamp_ns = driver_htstamp_ns + driver_htstamp.tv_nsec;
debug(1,"driver_htstamp: %f.", driver_htstamp_ns * 0.000000001);
#endif
*/
state_temp = snd_pcm_status_get_state(alsa_snd_pcm_status);
if ((state_temp == SND_PCM_STATE_RUNNING) || (state_temp == SND_PCM_STATE_DRAINING)) {
uint64_t update_timestamp_ns = update_timestamp.tv_sec;
update_timestamp_ns = update_timestamp_ns * 1000000000;
update_timestamp_ns = update_timestamp_ns + update_timestamp.tv_nsec;
// if the update_timestamp is zero, we take this to mean that the device doesn't report
// interrupt timings. (It could be that it's not a real hardware device.)
// so we switch to getting the delay the regular way
// i.e. using snd_pcm_delay ()
if (using_update_timestamps) {
if (update_timestamp_ns == 0)
*using_update_timestamps = YNDK_NO;
else
*using_update_timestamps = YNDK_YES;
}
// user information
if (update_timestamp_ns == 0) {
if (delay_type_notified != 1) {
debug(2, "alsa: update timestamps unavailable");
delay_type_notified = 1;
}
} else {
// diagnostic
if (delay_type_notified != 0) {
debug(2, "alsa: update timestamps available");
delay_type_notified = 0;
}
}
if (update_timestamp_ns == 0) {
ret = snd_pcm_delay(alsa_handle, &delay_temp);
} else {
delay_temp = snd_pcm_status_get_delay(alsa_snd_pcm_status);
/*
// It seems that the alsa library uses CLOCK_REALTIME before 1.0.28, even though
// the check for monotonic returns true. Might have to watch out for this.
#if SND_LIB_MINOR == 0 && SND_LIB_SUBMINOR < 28
clock_gettime(CLOCK_REALTIME, &tn);
#else
clock_gettime(CLOCK_MONOTONIC, &tn);
#endif
*/
if (use_monotonic_clock)
clock_gettime(CLOCK_MONOTONIC, &tn);
else
clock_gettime(CLOCK_REALTIME, &tn);
// uint64_t time_now_ns = tn.tv_sec * (uint64_t)1000000000 + tn.tv_nsec;
uint64_t time_now_ns = tn.tv_sec;
time_now_ns = time_now_ns * 1000000000;
time_now_ns = time_now_ns + tn.tv_nsec;
// if the delay is not zero and if stall_monitor_new_frame_count_time is non-zero, then
// if the delay is longer than the stall threshold
// and the delay is the same as it was, a stall has occurred.
if ((stall_monitor_new_frame_count_time != 0) && (delay_temp != 0)) {
uint64_t time_since_last_measurement = time_now_ns - stall_monitor_new_frame_count_time;
if ((time_since_last_measurement > stall_monitor_error_threshold) &&
(stall_monitor_new_frame_count == delay_temp)) {
debug(1, "DAC has stalled for %f seconds with a frame count of %ld.",
time_since_last_measurement * 1E-9, delay_temp);
debug(1, "time_now_ns: %" PRIu64 ", stall_monitor_new_frame_count_time: %" PRIu64 ".",
time_now_ns, stall_monitor_new_frame_count_time);
}
}
// for the next time...
stall_monitor_new_frame_count = delay_temp;
stall_monitor_new_frame_count_time = time_now_ns;
/*
// see if it's stalled
if ((stall_monitor_start_time != 0) && (stall_monitor_frame_count == delay_temp)) {
// hasn't outputted anything since the last call to delay()
if (((update_timestamp_ns - stall_monitor_start_time) >
stall_monitor_error_threshold) ||
((time_now_ns - stall_monitor_start_time) > stall_monitor_error_threshold)) {
debug(1,
"DAC seems to have stalled with time_now_ns: %" PRIu64
", update_timestamp_ns: %" PRIu64 ", stall_monitor_start_time %" PRIu64
", stall_monitor_error_threshold %" PRIu64 ", delay_temp %u.",
time_now_ns, update_timestamp_ns, stall_monitor_start_time,
stall_monitor_error_threshold, delay_temp);
// ret = sps_extra_code_output_stalled;
}
} // else {
stall_monitor_start_time = update_timestamp_ns;
stall_monitor_frame_count = delay_temp;
// }
*/
if (ret == 0) {
uint64_t delta = time_now_ns - update_timestamp_ns;
uint64_t frames_played_since_last_interrupt =
RATE_FROM_ENCODED_FORMAT(current_encoded_output_format);
frames_played_since_last_interrupt = frames_played_since_last_interrupt * delta;
frames_played_since_last_interrupt = frames_played_since_last_interrupt / 1000000000;
snd_pcm_sframes_t frames_played_since_last_interrupt_sized =
frames_played_since_last_interrupt;
if ((frames_played_since_last_interrupt_sized < 0) ||
((uint64_t)frames_played_since_last_interrupt_sized !=
frames_played_since_last_interrupt))
debug(1,
"overflow resizing frames_played_since_last_interrupt %" PRIx64
" to frames_played_since_last_interrupt %lx.",
frames_played_since_last_interrupt, frames_played_since_last_interrupt_sized);
delay_temp = delay_temp - frames_played_since_last_interrupt_sized;
}
}
} else { // not running, thus no delay information, thus can't check for
// stall
delay_temp = 0;
stall_monitor_new_frame_count_time = 0;
}
} else {
debug(1, "alsa: can't get device's status -- error %d.", ret);
}
} else {
debug(2, "alsa_handle is NULL in precision_delay_and_status!");
}
if (delay != NULL)
*delay = delay_temp;
if (state != NULL)
*state = state_temp;
debug(3, "precision_delay_and_status returning state: %d and delay %ld.", state_temp, delay_temp);
return ret;
}
static int delay(long *the_delay) {
// returns 0 if the device is in a valid state -- SND_PCM_STATE_RUNNING or
// SND_PCM_STATE_PREPARED
// or SND_PCM_STATE_DRAINING
// and returns the actual delay if running or 0 if prepared in *the_delay
// otherwise return an error code
// the error code could be a Unix errno code or a snderror code, or
// the sps_extra_code_output_stalled or the
// sps_extra_code_output_state_cannot_make_ready codes
int ret = 0;
snd_pcm_sframes_t my_delay = 0;
int oldState;
snd_pcm_state_t state;
pthread_setcancelstate(PTHREAD_CANCEL_DISABLE, &oldState); // make this un-cancellable
pthread_cleanup_debug_mutex_lock(&alsa_mutex, 10000, 0);
ret = delay_and_status(&state, &my_delay, NULL);
debug_mutex_unlock(&alsa_mutex, 0);
pthread_cleanup_pop(0);
pthread_setcancelstate(oldState, NULL);
if (the_delay != NULL) // can't imagine why this might happen
*the_delay = my_delay; // note: snd_pcm_sframes_t is a long
return ret;
}
static int stats(uint64_t *raw_measurement_time, uint64_t *corrected_measurement_time,
uint64_t *the_delay, uint64_t *frames_sent_to_dac) {
// returns 0 if the device is in a valid state -- SND_PCM_STATE_RUNNING or
// SND_PCM_STATE_PREPARED
// or SND_PCM_STATE_DRAINING.
// returns the actual delay if running or 0 if prepared in *the_delay
// returns the present value of frames_sent_for_playing
// otherwise return a non-zero value
int ret = 0;
*the_delay = 0;
int oldState;
snd_pcm_state_t state;
snd_pcm_sframes_t my_delay = 0; // this initialisation is to silence a clang warning
pthread_setcancelstate(PTHREAD_CANCEL_DISABLE, &oldState); // make this un-cancellable
pthread_cleanup_debug_mutex_lock(&alsa_mutex, 10000, 0);
if (alsa_handle == NULL) {
ret = alsa_handle_status;
} else {
*raw_measurement_time =
get_absolute_time_in_ns(); // this is not conditioned ("disciplined") by NTP
*corrected_measurement_time = get_monotonic_time_in_ns(); // this is ("disciplined") by NTP
ret = delay_and_status(&state, &my_delay, NULL);
}
if (ret == 0)
ret = frames_sent_break_occurred; // will be zero unless an error like an underrun occurred
else
ret = 1; // just indicate there was some kind of a break
frames_sent_break_occurred = 0; // reset it.
if (frames_sent_to_dac != NULL)
*frames_sent_to_dac = frames_sent_for_playing;
debug_mutex_unlock(&alsa_mutex, 0);
pthread_cleanup_pop(0);
pthread_setcancelstate(oldState, NULL);
uint64_t hd = my_delay; // note: snd_pcm_sframes_t is a long
*the_delay = hd;
// if (ret != 0)
// debug(1, "frames_sent_break_occurred? value is %d.", ret);
return ret;
}
static int do_play(void *buf, int samples) {
// assuming the alsa_mutex has been acquired
int ret = 0;
if ((samples != 0) && (buf != NULL)) {
int oldState;
pthread_setcancelstate(PTHREAD_CANCEL_DISABLE, &oldState); // make this un-cancellable
snd_pcm_state_t state;
snd_pcm_sframes_t my_delay;
ret = delay_and_status(&state, &my_delay, NULL);
if (ret == 0) { // will be non-zero if an error or a stall
// just check the state of the DAC
if ((state != SND_PCM_STATE_PREPARED) && (state != SND_PCM_STATE_RUNNING) &&
(state != SND_PCM_STATE_XRUN)) {
debug(1, "alsa: DAC in odd SND_PCM_STATE_* %d prior to writing.", state);
}
if (state == SND_PCM_STATE_XRUN) {
debug(1, "alsa: DAC in SND_PCM_STATE_XRUN prior to writing.");
ret = snd_pcm_recover(alsa_handle, ret, 1);
}
snd_pcm_state_t prior_state = state; // keep this for afterwards....
debug(4, "alsa: write %d frames.", samples);
ret = alsa_pcm_write(alsa_handle, buf, samples);
if (ret == -EIO) {
debug(1, "alsa: I/O Error.");
usleep(20000); // give it a breather...
}
if (ret > 0)
frames_sent_for_playing += ret; // this is the number of frames accepted
if (ret == samples) {
stall_monitor_new_frame_count += samples;
} else {
frames_sent_break_occurred = 1; // note than an output error has occurred
if (ret == -EPIPE) { /* underrun */
// It could be that the DAC was in the SND_PCM_STATE_XRUN state before
// sending the samples to be output. If so, it will still be in
// the SND_PCM_STATE_XRUN state after the call and it needs to be recovered.
// The underrun occurred in the past, so flagging an
// error at this point is misleading.
// In fact, having put samples in the buffer, we are about to fix it by now
// issuing a snd_pcm_recover().
// So, if state is SND_PCM_STATE_XRUN now, only report it if the state was
// not SND_PCM_STATE_XRUN prior to the call, i.e. report it only
// if we are not trying to recover from a previous underrun.
if (prior_state == SND_PCM_STATE_XRUN)
debug(1, "alsa: recovering from a previous underrun.");
else
debug(1, "alsa: underrun while writing %d samples to alsa device.", samples);
ret = snd_pcm_recover(alsa_handle, ret, 1);
} else if (ret == -ESTRPIPE) { /* suspended */
if (state != prior_state)
debug(1, "alsa: suspended while writing %d samples to alsa device.", samples);
if ((ret = snd_pcm_resume(alsa_handle)) == -ENOSYS)
ret = snd_pcm_prepare(alsa_handle);
} else if (ret >= 0) {
debug(1, "alsa: only %d of %d samples output.", ret, samples);
}
}
}
pthread_setcancelstate(oldState, NULL);
if (ret < 0) {
char errorstring[1024];
strerror_r(-ret, (char *)errorstring, sizeof(errorstring));
debug(1, "alsa: SND_PCM_STATE_* %d, error %d (\"%s\") writing %d samples to alsa device.",
state, ret, (char *)errorstring, samples);
}
if ((ret == -ENOENT) || (ret == -ENODEV)) // if the device isn't there...
handle_unfixable_error(-ret);
}
return ret;
}
static int do_open() {
int ret = 0;
if (alsa_backend_state != abm_disconnected)
debug(1, "alsa: do_open() -- asking to open the output device when it is already "
"connected");
if (alsa_handle == NULL) {
debug(3, "alsa: do_open() -- opening the output device");
ret = open_alsa_device();
if (ret == 0) {
mute_requested_internally = 0;
if (audio_alsa.volume)
do_volume(set_volume);
if (audio_alsa.mute) {
debug(2, "do_open() set_mute_state");
set_mute_state(); // the mute_requested_externally flag will have been
// set accordingly
// do_mute(0); // complete unmute
}
frames_sent_break_occurred = 1; // there is a discontinuity with
// any previously-reported frame count
frames_sent_for_playing = 0;
debug(3, "alsa: do_open() -- alsa_backend_state => abm_connected");
alsa_backend_state = abm_connected; // only do this if it really opened it.
} else {
if ((ret == -ENOENT) || (ret == -ENODEV)) // if the device isn't there...
handle_unfixable_error(-ret);
}
} else {
debug(1, "alsa: do_open() -- output device already open.");
}
return ret;
}
static int do_close() {
if (alsa_backend_state == abm_disconnected)
debug(3, "alsa: do_close() -- output device is already disconnected");
int derr = 0;
if (alsa_handle) {
debug(3, "alsa: do_close() -- closing the output device");
if ((derr = snd_pcm_drop(alsa_handle)))
debug(1, "Error %d (\"%s\") dropping output device.", derr, snd_strerror(derr));
usleep(20000); // wait for the hardware to do its trick. BTW, this make the function pthread
// cancellable
if ((derr = snd_pcm_hw_free(alsa_handle)))
debug(1, "Error %d (\"%s\") freeing the output device hardware.", derr, snd_strerror(derr));
debug(3, "alsa: do_close() -- closing alsa handle");
if ((derr = snd_pcm_close(alsa_handle)))
debug(1, "Error %d (\"%s\") closing the output device.", derr, snd_strerror(derr));
alsa_handle = NULL;
alsa_handle_status = -ENODEV; // no device open
} else {
debug(3, "alsa: do_close() -- output device is already closed.");
}
debug(3, "alsa: do_close() -- alsa_backend_state => abm_disconnected.");
alsa_backend_state = abm_disconnected;
return derr;
}
static int sub_flush() {
if (alsa_backend_state == abm_disconnected)
debug(1, "alsa: do_flush() -- asking to flush the output device when it is already "
"disconnected");
int derr = 0;
if (alsa_handle) {
debug(3, "alsa: do_flush() -- flushing the output device");
frames_sent_break_occurred = 1;
if ((derr = snd_pcm_drop(alsa_handle)))
debug(1, "Error %d (\"%s\") dropping output device.", derr, snd_strerror(derr));
if ((derr = snd_pcm_prepare(alsa_handle)))
debug(1, "Error %d (\"%s\") preparing output device after flush.", derr, snd_strerror(derr));
stall_monitor_new_frame_count = 0;
stall_monitor_new_frame_count_time = 0;
if (alsa_backend_state != abm_connected)
debug(2, "alsa: sub_flush() -- alsa_backend_state => abm_connected.");
alsa_backend_state = abm_connected;
} else {
debug(1, "alsa: do_flush() -- output device already closed.");
}
return derr;
}
static int play(void *buf, int samples, __attribute__((unused)) int sample_type,
__attribute__((unused)) uint32_t timestamp,
__attribute__((unused)) uint64_t playtime) {
// play() will change the state of the alsa_backend_mode to abm_playing
// also, if the present alsa_backend_state is abm_disconnected, then first the
// DAC must be
// connected
int ret = 0;
pthread_cleanup_debug_mutex_lock(&alsa_mutex, 50000, 0);
if (alsa_backend_state == abm_disconnected) {
ret = do_open();
if (ret == 0)
debug(2, "alsa: play() -- opened output device");
}
if (ret == 0) {
if (alsa_backend_state != abm_playing) {
debug(2, "alsa: play() -- alsa_backend_state => abm_playing");
alsa_backend_state = abm_playing;
// mute_requested_internally = 0; // stop requesting a mute for backend's own
// reasons, which might have been a flush
// debug(2, "play() set_mute_state");
// set_mute_state(); // try to action the request and return a status
// do_mute(0); // unmute for backend's reason
}
ret = do_play(buf, samples);
}
debug_mutex_unlock(&alsa_mutex, 0);
pthread_cleanup_pop(0); // release the mutex
return ret;
}
static void flush(void) {
pthread_cleanup_debug_mutex_lock(&alsa_mutex, 10000, 1);
if (alsa_backend_state != abm_disconnected) { // must be playing or connected...
// do nothing for a flush if config.keep_dac_busy is true
if (config.keep_dac_busy == 0) {
sub_flush();
}
} else {
debug(3, "alsa: flush() -- called on a disconnected alsa backend");
}
debug_mutex_unlock(&alsa_mutex, 3);
pthread_cleanup_pop(0); // release the mutex
}
static void stop(void) {
pthread_cleanup_debug_mutex_lock(&alsa_mutex, 10000, 1);
if (alsa_backend_state != abm_disconnected) { // must be playing or connected...
if (config.keep_dac_busy == 0) {
do_close();
}
} else
debug(3, "alsa: stop() -- called on a disconnected alsa backend");
debug_mutex_unlock(&alsa_mutex, 3);
pthread_cleanup_pop(0); // release the mutex
}
static void do_volume(double vol) { // caller is assumed to have the alsa_mutex when
// using this function
debug(3, "Setting volume db to %f.", vol);
int oldState;
pthread_setcancelstate(PTHREAD_CANCEL_DISABLE, &oldState); // make this un-cancellable
set_volume = vol;
pthread_cleanup_debug_mutex_lock(&alsa_mixer_mutex, 1000, 1);
if (volume_set_request && (open_mixer() == 0)) {
if (has_softvol) {
if (ctl && elem_id) {
snd_ctl_elem_value_t *value;
long raw;
if (snd_ctl_convert_from_dB(ctl, elem_id, vol, &raw, 0) < 0)
debug(1, "Failed converting dB gain to raw volume value for the "
"software volume control.");
snd_ctl_elem_value_alloca(&value);
snd_ctl_elem_value_set_id(value, elem_id);
snd_ctl_elem_value_set_integer(value, 0, raw);
snd_ctl_elem_value_set_integer(value, 1, raw);
if (snd_ctl_elem_write(ctl, value) < 0)
debug(1, "Failed to set playback dB volume for the software volume "
"control.");
}
} else {
if (volume_based_mute_is_active == 0) {
// debug(1,"Set alsa volume.");
do_snd_mixer_selem_set_playback_dB_all(alsa_mix_elem, vol);
} else {
debug(2, "Not setting volume because volume-based mute is active");
}
}
volume_set_request = 0; // any external request that has been made is now satisfied
close_mixer();
}
debug_mutex_unlock(&alsa_mixer_mutex, 3);
pthread_cleanup_pop(0); // release the mutex
pthread_setcancelstate(oldState, NULL);
}
static void volume(double vol) {
volume_set_request = 1; // an external request has been made to set the volume
do_volume(vol);
}
static int mute(int mute_state_requested) { // these would be for external reasons, not
// because of the
// state of the backend.
mute_requested_externally = mute_state_requested; // request a mute for external reasons
debug(2, "mute(%d) set_mute_state", mute_state_requested);
return set_mute_state();
}
/*
static void alsa_buffer_monitor_thread_cleanup_function(__attribute__((unused)) void
*arg) {
debug(1, "alsa: alsa_buffer_monitor_thread_cleanup_function called.");
}
*/
static void *alsa_buffer_monitor_thread_code(__attribute__((unused)) void *arg) {
// #include <syscall.h>
// debug(1, "alsa_buffer_monitor_thread_code PID %d", syscall(SYS_gettid));
// Wait until the output configuration has been set by the main program
debug(2, "alsa: alsa_buffer_monitor_thread_code started.");
int frame_count = 0;
int error_count = 0;
int error_detected = 0;
int64_t sleep_time_actual_ns = 0; // actual sleep time since last check, or zero
int okb = -1;
while (config.keep_dac_busy == 0)
usleep(10000);
debug(1, "alsa: get initial disable standby parameters for rate/channels: %u/%u.",
disable_standby_mode_default_rate, disable_standby_mode_default_channels);
while (get_permissible_configuration_settings() != 0) {
debug(1, "wait 50 ms to check again for success");
usleep(50000);
}
current_encoded_output_format =
get_configuration(disable_standby_mode_default_channels, disable_standby_mode_default_rate,
disable_standby_mode_default_format);
debug(1, "alsa: disable standby initial parameters: %s.",
short_format_description(current_encoded_output_format));
// if too many play errors occur early on, we will turn off the disable standby mode
while (error_detected == 0) {
int keep_dac_busy_has_just_gone_off = 0;
if (okb != config.keep_dac_busy) {
if ((okb != 0) && (config.keep_dac_busy == 0)) {
keep_dac_busy_has_just_gone_off = 1;
}
debug(2, "keep_dac_busy is now \"%s\"", config.keep_dac_busy == 0 ? "no" : "yes");
okb = config.keep_dac_busy;
}
if ((config.keep_dac_busy != 0) && (alsa_device_initialised == 0)) {
debug(2, "alsa: alsa_buffer_monitor_thread_code() preparing for use and initialising.");
alsa_device_init();
alsa_device_initialised = 1;
}
int sleep_time_us = (int)(config.disable_standby_mode_silence_scan_interval * 1000000);
if (sleep_time_actual_ns > ((8 * sleep_time_us * 1000) / 4))
debug(1,
"alsa_buffer_monitor_thread_code sleep was %.6f sec but request was for %.6f sec. "
"Disabling standby may not work properly!",
sleep_time_actual_ns * 0.000000001, config.disable_standby_mode_silence_scan_interval);
pthread_cleanup_debug_mutex_lock(&alsa_mutex, 200000, 0);
// check possible state transitions here
if ((alsa_backend_state == abm_disconnected) && (config.keep_dac_busy != 0)) {
// open the dac and move to abm_connected mode
if (do_open() == 0) {
debug(2,
"alsa: alsa_buffer_monitor_thread_code() -- output device opened; "
"alsa_backend_state from abm_disconnected => abm_connected. error_detected = %d",
error_detected);
} else {
debug(1, "alsa_buffer_monitor_thread_code: can't open output device -- terminating");
error_detected = 1;
}
} else if ((alsa_backend_state != abm_disconnected) && (keep_dac_busy_has_just_gone_off != 0)) {
debug(2, "alsa: alsa_buffer_monitor_thread_code() -- closing the output "
"device");
do_close();
}
// now, if the backend is not in the abm_disconnected state
// and config.keep_dac_busy is true (at the present, this has to be the case
// to be in the
// abm_connected state in the first place...) then do the silence-filling
// thing, if needed /* only if the output device is capable of precision delay */.
if ((alsa_backend_state != abm_disconnected) && (config.keep_dac_busy != 0) &&
(error_detected == 0) /* && precision_delay_available() */) {
int reply;
long buffer_size = 0;
snd_pcm_state_t state;
reply = delay_and_status(&state, &buffer_size, NULL);
if (reply != 0) {
buffer_size = 0;
char errorstring[1024];
strerror_r(-reply, (char *)errorstring, sizeof(errorstring));
debug(1, "alsa: alsa_buffer_monitor_thread_code delay error %d: \"%s\".", reply,
(char *)errorstring);
}
uint64_t current_delay = 0;
if (buffer_size < 0) {
debug(1, "delay of less than 0: %ld.", buffer_size);
current_delay = 0;
} else {
current_delay = buffer_size;
}
if (current_delay < minimum_dac_queue_size) {
minimum_dac_queue_size = current_delay; // update for display later
}
long buffer_size_threshold = (long)(config.disable_standby_mode_silence_threshold *
RATE_FROM_ENCODED_FORMAT(current_encoded_output_format));
// debug(1, "current_delay: %" PRIu64 ", buffer_size: %ld, buffer_size_threshold %ld,
// frames_of_silence: %d.", current_delay, buffer_size, buffer_size_threshold,
// buffer_size_threshold - buffer_size + current_alsa_configuration->rate / 10);
size_t size_of_silence_buffer;
// debug(1, "buffer_size %d, buffer_size_threshold %d.", buffer_size,
// buffer_size_threshold);
if (buffer_size < buffer_size_threshold) {
int frames_of_silence = buffer_size_threshold - buffer_size +
RATE_FROM_ENCODED_FORMAT(current_encoded_output_format) / 10;
size_of_silence_buffer =
frames_of_silence *
fr[FORMAT_FROM_ENCODED_FORMAT(current_encoded_output_format)].sample_size *
CHANNELS_FROM_ENCODED_FORMAT(current_encoded_output_format);
void *silence = calloc(size_of_silence_buffer, 1);
if (silence == NULL) {
warn("disable_standby_mode has been turned off because a memory allocation error "
"occurred.");
error_detected = 1;
} else {
int ret;
pthread_cleanup_push(malloc_cleanup, &silence);
int use_dither = 0;
if ((alsa_mix_ctrl == NULL) &&
(((config.ignore_volume_control == 0) && (config.airplay_volume != 0.0)) ||
(config.playback_mode == ST_mono)))
use_dither = 1;
dither_random_number_store =
generate_zero_frames(silence, frames_of_silence,
use_dither, // i.e. with dither
dither_random_number_store, current_encoded_output_format);
ret = do_play(silence, frames_of_silence);
debug(4, "Played %u frames of silence on %u channels, equal to %zu bytes.",
frames_of_silence, CHANNELS_FROM_ENCODED_FORMAT(current_encoded_output_format),
size_of_silence_buffer);
frame_count++;
pthread_cleanup_pop(1); // free malloced buffer
if (ret < 0) {
error_count++;
char errorstring[1024];
strerror_r(-ret, (char *)errorstring, sizeof(errorstring));
debug(2,
"alsa: alsa_buffer_monitor_thread_code error %d (\"%s\") writing %d samples "
"to alsa device -- %d errors in %d trials.",
ret, (char *)errorstring, frames_of_silence, error_count, frame_count);
if ((error_count > 40) && (frame_count < 100)) {
warn("disable_standby_mode has been turned off because too many underruns "
"occurred. Is Shairport Sync outputting to a virtual device or running in a "
"virtual machine?");
error_detected = 1;
}
}
}
}
}
debug_mutex_unlock(&alsa_mutex, 0);
pthread_cleanup_pop(0); // release the mutex
uint64_t tsb = get_absolute_time_in_ns();
usleep(sleep_time_us); // has a cancellation point in it
sleep_time_actual_ns = get_absolute_time_in_ns() - tsb;
}
pthread_exit(NULL);
}
static int32_t get_configuration(unsigned int channels, unsigned int rate, unsigned int format) {
// pass in SPS_FORMAT_AUTO because we want the best (deepest) format.
// first, check that the device is there!
snd_pcm_t *temp_alsa_handle = NULL;
int response = snd_pcm_open(&temp_alsa_handle, alsa_out_dev, SND_PCM_STREAM_PLAYBACK, 0);
;
if ((response == 0) && (temp_alsa_handle != NULL)) {
response = snd_pcm_close(temp_alsa_handle);
if (response != 0) {
char errorstring[1024];
strerror_r(-response, (char *)errorstring, sizeof(errorstring));
debug(1, "error %d closing probed alsa output device \"%s\".", -response, alsa_out_dev);
}
} else if (response == -EBUSY) {
response = 0; // busy is okay -- it means the device exists
} else {
char errorstring[1024];
strerror_r(-response, (char *)errorstring, sizeof(errorstring));
debug(3,
"the alsa output device called \"%s\" can not be accessed. Error %d (\"%s\"). Maybe it "
"doesn't exist or is not ready yet...",
alsa_out_dev, -response, errorstring);
}
// if we can access the device, then search for configurations
if (response == 0)
response = search_for_suitable_configuration(channels, rate, format, &check_configuration);
return response;
}
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