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Add graph reorder callback, this is where we now compute the output latencies.

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Jörn Nettingsmeier
2019-02-16 01:53:49 +00:00
parent f1ba07ff2b
commit bda8b99cda
1 changed files with 17 additions and 15 deletions
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audio_jack.c
+17 -15
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@@ -134,7 +134,15 @@ static int process(jack_nframes_t nframes, __attribute__((unused)) void *arg) {
return 0;
}
// FIXME: set_graph_order_callback(), recompute latencies here!
static int graph(__attribute__((unused)) void * arg) {
jack_port_get_latency_range(left_port, JackPlaybackLatency, &latest_left_latency_range);
jack_port_get_latency_range(right_port, JackPlaybackLatency, &latest_right_latency_range);
debug(1, "JACK graph reorder callback called. Current latencies to terminal downstream port:\n"
"\tLmin = %d, Lmax = %d, Rmin = %d, Rmax = %d",
latest_left_latency_range.min, latest_left_latency_range.max,
latest_right_latency_range.min, latest_right_latency_range.max);
return 0;
}
static void error(const char *desc) { debug(2, "jackd error: \"%s\"", desc); }
@@ -172,9 +180,6 @@ int jack_init(__attribute__((unused)) int argc, __attribute__((unused)) char **a
die("Can't allocate %d bytes for the JACK ringbuffer.", buffer_size);
jack_ringbuffer_mlock(jackbuf); // lock buffer into memory so that it never gets paged out
jack_set_error_function(&error);
jack_set_info_function(&info);
pthread_mutex_lock(&client_mutex);
jack_status_t status;
client = jack_client_open(config.jack_client_name, JackNoStartServer, &status);
@@ -187,6 +192,10 @@ int jack_init(__attribute__((unused)) int argc, __attribute__((unused)) char **a
sample_rate);
}
jack_set_process_callback(client, &process, 0);
jack_set_graph_order_callback(client, &graph, 0);
jack_set_error_function(&error);
jack_set_info_function(&info);
left_port = jack_port_register(client, "out_L", JACK_DEFAULT_AUDIO_TYPE,
JackPortIsOutput, 0);
right_port = jack_port_register(client, "out_R",
@@ -225,7 +234,7 @@ void jack_flush() {
}
int jack_delay(long *the_delay) {
jack_nframes_t base_latency;
// semantics change: we now look at the last transfer into the lock-free ringbuffer, not
// into the jack buffers directly (because locking those would violate real-time constraints).
// on average, that should lead to just a constant additional latency. the old comment still applies:
@@ -234,7 +243,6 @@ int jack_delay(long *the_delay) {
// but then a transfer could occur and we would get the buffer occupancy after another transfer
// had occurred
// so we could "lose" a full transfer (e.g. 1024 frames @ 44,100 fps ~ 23.2 milliseconds)
pthread_mutex_lock(&buffer_mutex);
int64_t time_now = get_absolute_time_in_fp();
// this is the time back to the last time data
@@ -248,16 +256,10 @@ int jack_delay(long *the_delay) {
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;
// use the average of the left and right maximum latencies. if max is really different from min,
// there is an anomaly in the graph that we don't have any hope of fixing anyways
base_latency = (latest_left_latency_range.max + 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);
return 0;