nils/shairport-sync
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Get it working for multiples of 44100 again. It's stuck accepting only 44,100 fps input for the moment.

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This commit is contained in:
Mike Brady
2021-06-06 15:51:39 +01:00
parent 93aefbd8ea
commit 5c48580db9
1 changed files with 55 additions and 19 deletions
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player.c
+55 -19
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@@ -96,6 +96,29 @@
#include "activity_monitor.h"
// sign extending rtptime calculations to 64 bit is needed from time to time.
// the standard rtptime is unsigned 32 bits,
// so you can do modulo 2^32 difference calculations
// and get a signed result simply by typing the result as a signed 32-bit number
// So long as you can be sure the numbers are within 2^31 of each other,
// the sign of the result calculated in this way indicates which comes after which
// so if you subtract a from b and the result is positive,
// b is the same as or comes after a in module 2^32 order.
// We want to do the same with the rtptime calculations for multiples of
// the rtptimes (1, 2, 4 or 8 times), and we want to do this in signed 64-bit
// so we need to sign extend these modulo 2^32, 2^33, 2^34, or 2^35 but unsigned
// numbers on the same basis
// See http://graphics.stanford.edu/~seander/bithacks.html#FixedSignExtend
// and https://stackoverflow.com/a/31655073/2942008
// of which this is a slight variation
#define SIGNEX(v, sb) (((v) & ((1 << (sb + 1)) - 1)) | (((v) & (1 << (sb))) ? ~((1 << (sb))-1) : 0))
// make the first audio packet deliberately early to bias the sync error of
// the very first packet, making the error more likely to be too early
// rather than too late. It it's too early,
@@ -1082,7 +1105,7 @@ static abuf_t *buffer_get_frame(rtsp_conn_info *conn) {
int64_t lt = conn->first_packet_time_to_play - local_time_now;
debug(2, "Connection %d: Lead time for first frame %" PRId64 ": %f seconds.",
debug(1, "Connection %d: Lead time for first frame %" PRId64 ": %f seconds.",
conn->connection_number, conn->first_packet_timestamp, lt * 0.000000001);
int64_t lateness = local_time_now - conn->first_packet_time_to_play;
@@ -1787,7 +1810,28 @@ void *player_thread_func(void *arg) {
conn->output_sample_ratio = config.output_rate / conn->input_rate;
// debug(1, "Output sample ratio is %d.", conn->output_sample_ratio);
int output_rtptime_sign_bit;
switch (conn->output_sample_ratio) {
case 1:
output_rtptime_sign_bit = 31;
break;
case 2:
output_rtptime_sign_bit = 32;
break;
case 4:
output_rtptime_sign_bit = 33;
break;
case 8:
output_rtptime_sign_bit = 34;
break;
default:
debug(1, "error with output ratio -- can't calculate sign bit number");
output_rtptime_sign_bit = 31;
break;
}
debug(1, "Output sample ratio is %d.", conn->output_sample_ratio);
debug(1, "Output output_rtptime_sign_bit: %d.", output_rtptime_sign_bit);
conn->max_frame_size_change =
1 * conn->output_sample_ratio; // we add or subtract one frame at the nominal
@@ -2304,17 +2348,19 @@ void *player_thread_func(void *arg) {
if (resp == 0) {
uint32_t should_be_frame_32;
// this is denominated in the frame rate of the incoming stream
local_time_to_frame(local_time_now, &should_be_frame_32, conn);
int64_t should_be_frame = ((int64_t)should_be_frame_32) * conn->output_sample_ratio;
int64_t delay =
should_be_frame - (inframe->given_timestamp * conn->output_sample_ratio -
current_delay); // all int64_t
int64_t should_be_frame = should_be_frame_32;
should_be_frame = should_be_frame * conn->output_sample_ratio;
sync_error = delay; // int64_t from int64_t - int32_t, so okay
// current_delay is denominated in the frame rate of the outgoing stream
int64_t will_be_frame = inframe->given_timestamp;
will_be_frame = will_be_frame * conn->output_sample_ratio;
will_be_frame = (will_be_frame - current_delay) & ((1 << (output_rtptime_sign_bit + 1)) - 1);
// debug(1, "Sync error on frame %u is %" PRId64 " frames.", inframe->given_timestamp,
// sync_error);
sync_error =
SIGNEX(should_be_frame - will_be_frame, output_rtptime_sign_bit) ; // all int64_t
if (at_least_one_frame_seen_this_session == 0) {
at_least_one_frame_seen_this_session = 1;
@@ -2376,16 +2422,6 @@ void *player_thread_func(void *arg) {
if ((config.no_sync == 0) && (inframe->given_timestamp != 0) &&
(config.resyncthreshold > 0.0) &&
(abs_sync_error > config.resyncthreshold * config.output_rate)) {
/*
if (abs_sync_error > 3 * config.output_rate) {
warn("Very large sync error: %" PRId64 " frames, with should_be_frame: %" PRId64
", nt: %" PRId64 ", current_delay: %" PRId64 ", given timestamp %" PRIX32
", reference timestamp %" PRIX32 ", should_be_frame %" PRIX32 ".",
sync_error, should_be_frame, nt, current_delay, inframe->given_timestamp,
reference_timestamp, should_be_frame_32);
}
*/
sync_error_out_of_bounds++;
} else {
sync_error_out_of_bounds = 0;