| Message ID | 20220122125745.5037-6-vr_qemu@t-online.de |
|---|---|
| State | New |
| Headers | show |
| Series | reduce audio playback latency | expand |
On Samstag, 22. Januar 2022 13:57:36 CET Volker Rümelin wrote: > The next patch reduces the effective qemu playback buffer size > by timer-period. Increase the number of jack audio buffers by > one to preserve the total effective buffer size. The size of one > jack audio buffer is 512 samples. With audio defaults that's > 512 samples / 44100 samples/s = 11.6 ms and only slightly larger > than the timer-period of 10 ms. > > The larger jack audio buffer increases audio dropout safety, > because the high priority jack-audio worker threads can provide > audio data for a longer period of time as with a smaller buffer > and more audio data in the mixing engine buffer that they can't > access. > > Signed-off-by: Volker Rümelin <vr_qemu@t-online.de> Reviewed-by: Christian Schoenebeck <qemu_oss@crudebyte.com> > --- > audio/jackaudio.c | 4 ++-- > 1 file changed, 2 insertions(+), 2 deletions(-) > > diff --git a/audio/jackaudio.c b/audio/jackaudio.c > index 317009e936..26246c3a8b 100644 > --- a/audio/jackaudio.c > +++ b/audio/jackaudio.c > @@ -483,8 +483,8 @@ static int qjack_client_init(QJackClient *c) > c->buffersize = 512; > } > > - /* create a 2 period buffer */ > - qjack_buffer_create(&c->fifo, c->nchannels, c->buffersize * 2); > + /* create a 3 period buffer */ > + qjack_buffer_create(&c->fifo, c->nchannels, c->buffersize * 3); > > qjack_client_connect_ports(c); > c->state = QJACK_STATE_RUNNING;
diff --git a/audio/jackaudio.c b/audio/jackaudio.c index 317009e936..26246c3a8b 100644 --- a/audio/jackaudio.c +++ b/audio/jackaudio.c @@ -483,8 +483,8 @@ static int qjack_client_init(QJackClient *c) c->buffersize = 512; } - /* create a 2 period buffer */ - qjack_buffer_create(&c->fifo, c->nchannels, c->buffersize * 2); + /* create a 3 period buffer */ + qjack_buffer_create(&c->fifo, c->nchannels, c->buffersize * 3); qjack_client_connect_ports(c); c->state = QJACK_STATE_RUNNING;
The next patch reduces the effective qemu playback buffer size by timer-period. Increase the number of jack audio buffers by one to preserve the total effective buffer size. The size of one jack audio buffer is 512 samples. With audio defaults that's 512 samples / 44100 samples/s = 11.6 ms and only slightly larger than the timer-period of 10 ms. The larger jack audio buffer increases audio dropout safety, because the high priority jack-audio worker threads can provide audio data for a longer period of time as with a smaller buffer and more audio data in the mixing engine buffer that they can't access. Signed-off-by: Volker Rümelin <vr_qemu@t-online.de> --- audio/jackaudio.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-)