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Do not re-check JACK graph latency every time delay() is called. Do not register a latency callback with jack.

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This commit is contained in:
Jörn Nettingsmeier
2019-02-15 16:41:20 +00:00
parent 8347223986
commit 9c57fe43cc
1 changed files with 20 additions and 8 deletions
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audio_jack.c
+20 -8
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@@ -263,6 +263,7 @@ void default_jack_error_callback(const char *desc) { debug(2, "jackd error: \"%s
void default_jack_info_callback(const char *desc) { inform("jackd information: \"%s\"", desc); }
/*
void default_jack_set_latency_callback(jack_latency_callback_mode_t mode,
__attribute__((unused)) void *arg) {
if (mode == JackPlaybackLatency) {
@@ -280,6 +281,7 @@ void default_jack_set_latency_callback(jack_latency_callback_mode_t mode,
debug(1, "playback latency callback: %" PRIu32 ".", jack_latency);
}
}
*/
int jack_is_running() {
int reply = -1; // meaning jack is not running
@@ -325,16 +327,19 @@ int jack_client_open_if_needed(void) {
sample_rate = jack_get_sample_rate(client);
// debug(1, "jackaudio sample rate = %" PRId32 ".", sample_rate);
if (sample_rate == 44100) {
if (jack_set_latency_callback(client, default_jack_set_latency_callback, NULL) == 0) {
// FIXME: shairport-sync has no need for a latency callback, it's a leaf node with only outputs.
// If in the future some jack video player wants to resync to shairplay-sync audio, then yes, but
// the current usage seems to suggest a misunderstanding.
// if (jack_set_latency_callback(client, default_jack_set_latency_callback, NULL) == 0) {
if (jack_activate(client)) {
debug(1, "jackaudio cannot activate client");
} else {
debug(2, "jackaudio client opened.");
client_is_open = 1;
}
} else {
debug(1, "jackaudio cannot set latency callback");
}
// } else {
// debug(1, "jackaudio cannot set latency callback");
// }
} else {
inform(
"jackaudio is running at the wrong speed (%d) for Shairport Sync, which must be 44100",
@@ -505,15 +510,22 @@ int jack_delay(long *the_delay) {
// subsequent transfer because transfer is blocked
// by the mutex
size_t audio_occupancy_now = jack_ringbuffer_read_space(jackbuf) / bytes_per_frame;
debug(1, "JN: audio_occupancy_now is %d.", audio_occupancy_now);
pthread_mutex_unlock(&buffer_mutex);
int64_t frames_processed_since_latest_latency_check = (delta * 44100) >> 32;
// FIXME: this should only be done if there was an actual change, i.e. on the jack graph reorder
// callback, to update a static variable which can be checked here. For now, use a fixed arbitrary value:
jack_nframes_t base_latency = 0;
// debug(1,"delta: %" PRId64 " frames.",frames_processed_since_latest_latency_check);
jack_nframes_t base_latency = (latest_left_latency_range.min + latest_left_latency_range.max) / 2;
if (base_latency == 0)
base_latency = (latest_right_latency_range.min + latest_right_latency_range.max) / 2;
// jack_nframes_t base_latency = (latest_left_latency_range.min + latest_left_latency_range.max) / 2;
// if (base_latency == 0)
// base_latency = (latest_right_latency_range.min + latest_right_latency_range.max) / 2;
*the_delay = base_latency + audio_occupancy_now - frames_processed_since_latest_latency_check;
// debug(1,"reporting a delay of %d frames",*the_delay);
debug(1,"reporting a delay of %d frames",*the_delay);
return 0;
}