[Qemu-devel] [PATCH 25/51] paaudio: fix playback glitches

[Volker Rümelin]

Hi,

a better way to fix the playback glitches is to use a bigger playback
buffer on pulseaudio server side. I suggest you replace your patch with
a patch like this one:

diff --git a/audio/paaudio.c b/audio/paaudio.c
index fea6071..8bd5b91 100644
--- a/audio/paaudio.c
+++ b/audio/paaudio.c
@@ -554,7 +554,7 @@ static int qpa_init_out(HWVoiceOut *hw, struct audsettings 
*as,
  * qemu audio tick runs at 100 Hz (by default), so processing
  * data chunks worth 10 ms of sound should be a good fit.
  */
-ba.tlength = pa_usec_to_bytes (10 * 1000, );
+ba.tlength = pa_usec_to_bytes (50 * 1000, );
 ba.minreq = pa_usec_to_bytes (5 * 1000, );
 ba.maxlength = -1;
 ba.prebuf = -1;

I tested your patch and while it really improves audio playback, I
still notice audio drop-outs. With my suggestion I experience no
playback glitches.

Regards,
Volker

[Qemu-devel] [PATCH 25/51] paaudio: fix playback glitches

[Kővágó, Zoltán]

Pulseaudio normally assumes that when the server wants it, the client
can generate the audio samples and send it right away.  Unfortunately
this is not the case with QEMU -- it's up to the emulated system when
does it generate the samples.  Buffering the samples and sending them
from a background thread is just a workaround, that doesn't work too
well.  Instead enable pa's compatibility support and let pa worry about
the details.

Signed-off-by: Kővágó, Zoltán 
---
 audio/paaudio.c | 6 ++
 1 file changed, 2 insertions(+), 4 deletions(-)

diff --git a/audio/paaudio.c b/audio/paaudio.c
index 4206dd0..2d10afd 100644
--- a/audio/paaudio.c
+++ b/audio/paaudio.c
@@ -510,10 +510,8 @@ static pa_stream *qpa_simple_new (
 
 flags =
 PA_STREAM_INTERPOLATE_TIMING
-#ifdef PA_STREAM_ADJUST_LATENCY
-|PA_STREAM_ADJUST_LATENCY
-#endif
-|PA_STREAM_AUTO_TIMING_UPDATE;
+|PA_STREAM_AUTO_TIMING_UPDATE
+|PA_STREAM_EARLY_REQUESTS;
 
 if (dev) {
 /* don't move the stream if the user specified a sink/source */
-- 
2.7.0