loopback: Fix sink latency calculation if source is alsa source with fixed latency

When an alsa source with fixed latency is used, the actual latency of the source
will only be one fragment size. This is not taken into account when the required
sink latency is calculated.

This patch fixes the issue.

Part-of: <https://gitlab.freedesktop.org/pulseaudio/pulseaudio/-/merge_requests/451>
This commit is contained in:
Georg Chini 2021-01-04 21:08:05 +01:00 committed by PulseAudio Marge Bot
parent f18f55bb5e
commit 0efae0488c

View file

@ -1016,6 +1016,14 @@ static void set_sink_input_latency(struct userdata *u, pa_sink *sink) {
if (u->min_source_latency > requested_latency) {
latency = PA_MAX(u->latency, u->minimum_latency);
requested_latency = (latency - u->min_source_latency) / 2;
/* In the case of a fixed alsa source, u->minimum_latency is calculated from
* the default fragment size while u->min_source_latency is the reported minimum
* of the source latency (nr_of_fragments * fragment_size). This can lead to a
* situation where u->minimum_latency < u->min_source_latency. We only fall
* back to use the fragment size instead of min_source_latency if the calculation
* above does not deliver a usable result. */
if (u->fixed_alsa_source && u->min_source_latency >= latency)
requested_latency = (latency - u->core->default_fragment_size_msec * PA_USEC_PER_MSEC) / 2;
}
latency = PA_CLAMP(requested_latency , u->min_sink_latency, u->max_sink_latency);