/* * stdout output driver. This file is part of Shairport Sync. * Copyright (c) Mike Brady 2015--2025 * * Based on pipe output driver * Copyright (c) James Laird 2013 * 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. */ #include "audio.h" #include "common.h" #include #include #include #include #include #include static int fd = STDOUT_FILENO; static int warned = 0; static unsigned int bytes_per_frame = 0; static int play(void *buf, int samples, __attribute__((unused)) int sample_type, __attribute__((unused)) uint32_t timestamp, __attribute__((unused)) uint64_t playtime) { char errorstring[1024]; if (bytes_per_frame == 0) debug(1, "stdout: bytes per frame not initialised before play()!"); int rc = write(fd, buf, samples * bytes_per_frame); if ((rc < 0) && (warned == 0)) { strerror_r(errno, (char *)errorstring, 1024); warn("error %d writing to stdout (fd: %d): \"%s\".", errno, fd, errorstring); warned = 1; } return rc; } static int init(__attribute__((unused)) int argc, __attribute__((unused)) char **argv) { // set up default values first config.audio_backend_buffer_desired_length = 1.0; config.audio_backend_latency_offset = 0; // 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_AIRPLAY_2 parse_audio_options("stdout", (1 << SPS_FORMAT_S32_LE), (1 << SPS_RATE_48000), (1 << 2)); #else parse_audio_options("stdout", (1 << SPS_FORMAT_S16_LE), (1 << SPS_RATE_44100), (1 << 2)); #endif return 0; } static int32_t get_configuration(unsigned int channels, unsigned int rate, unsigned int format) { // use the standard format/rate/channel search to get a suitable configuration. No // check_configuration() method needs to be passed to search_for_suitable_configuration() because // it will always return a valid choice based on any settings and the defaults return search_for_suitable_configuration(channels, rate, format, NULL); } static int configure(int32_t requested_encoded_format, __attribute__((unused)) char **channel_map) { int response = 0; unsigned int bytes_per_sample = sps_format_sample_size(FORMAT_FROM_ENCODED_FORMAT(requested_encoded_format)); if (bytes_per_sample == 0) { debug(1, "stdout: unknown output format."); bytes_per_sample = 4; // emergency hack response = EINVAL; } bytes_per_frame = bytes_per_sample * CHANNELS_FROM_ENCODED_FORMAT(requested_encoded_format); return response; } audio_output audio_stdout = {.name = "stdout", .help = NULL, .init = &init, .deinit = NULL, .get_configuration = &get_configuration, .configure = &configure, .start = NULL, .stop = NULL, .is_running = NULL, .flush = NULL, .delay = NULL, .stats = NULL, .play = &play, .volume = NULL, .parameters = NULL, .mute = NULL};