| Message ID | 20230121094735.11644-10-vr_qemu@t-online.de (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | audio: more improvements | expand |
On 21/1/23 10:47, Volker Rümelin wrote: > The currently used default playback settings in the ALSA audio > backend are a bit unfortunate. With a few emulated audio devices, > audio playback does not work properly. Here is a short part of > the debug log while audio is playing (elapsed time in seconds). > > audio: Elapsed since last alsa run (running): 0.046244 > audio: Elapsed since last alsa run (running): 0.023137 > audio: Elapsed since last alsa run (running): 0.023170 > audio: Elapsed since last alsa run (running): 0.023650 > audio: Elapsed since last alsa run (running): 0.060802 > audio: Elapsed since last alsa run (running): 0.031931 > > For some audio devices the time of more than 23ms between updates > is too long. > > Set the period time to 5.8ms so that the maximum time between > two updates typically does not exceed 11ms. This roughly matches > the 10ms period time when doing playback with the audio timer. > After this patch the debug log looks like this. > > audio: Elapsed since last alsa run (running): 0.011919 > audio: Elapsed since last alsa run (running): 0.005788 > audio: Elapsed since last alsa run (running): 0.005995 > audio: Elapsed since last alsa run (running): 0.011069 > audio: Elapsed since last alsa run (running): 0.005901 > audio: Elapsed since last alsa run (running): 0.006084 > > Acked-by: Christian Schoenebeck <qemu_oss@crudebyte.com> > Signed-off-by: Volker Rümelin <vr_qemu@t-online.de> > --- > audio/alsaaudio.c | 11 ++++------- > 1 file changed, 4 insertions(+), 7 deletions(-) > > diff --git a/audio/alsaaudio.c b/audio/alsaaudio.c > index 5f50dfa0bf..0cc982e61f 100644 > --- a/audio/alsaaudio.c > +++ b/audio/alsaaudio.c > @@ -913,17 +913,14 @@ static void *alsa_audio_init(Audiodev *dev) > alsa_init_per_direction(aopts->in); > alsa_init_per_direction(aopts->out); > > - /* > - * need to define them, as otherwise alsa produces no sound > - * doesn't set has_* so alsa_open can identify it wasn't set by the user > - */ > + /* don't set has_* so alsa_open can identify it wasn't set by the user */ > if (!dev->u.alsa.out->has_period_length) { > - /* 1024 frames assuming 44100Hz */ > - dev->u.alsa.out->period_length = 1024 * 1000000 / 44100; > + /* 256 frames assuming 44100Hz */ > + dev->u.alsa.out->period_length = 5805; Please use DIV_ROUND_UP(): DIV_ROUND_UP(1000000ul << 8, 44100); Or DIV_ROUND_UP(512 * 1000000ul, 44100); > } > if (!dev->u.alsa.out->has_buffer_length) { > /* 4096 frames assuming 44100Hz */ > - dev->u.alsa.out->buffer_length = 4096ll * 1000000 / 44100; > + dev->u.alsa.out->buffer_length = 92880; Ditto: DIV_ROUND_UP(1000000ul << 12, 44100); > } > > /*
Am 23.01.23 um 08:43 schrieb Philippe Mathieu-Daudé: > On 21/1/23 10:47, Volker Rümelin wrote: >> The currently used default playback settings in the ALSA audio >> backend are a bit unfortunate. With a few emulated audio devices, >> audio playback does not work properly. Here is a short part of >> the debug log while audio is playing (elapsed time in seconds). >> >> audio: Elapsed since last alsa run (running): 0.046244 >> audio: Elapsed since last alsa run (running): 0.023137 >> audio: Elapsed since last alsa run (running): 0.023170 >> audio: Elapsed since last alsa run (running): 0.023650 >> audio: Elapsed since last alsa run (running): 0.060802 >> audio: Elapsed since last alsa run (running): 0.031931 >> >> For some audio devices the time of more than 23ms between updates >> is too long. >> >> Set the period time to 5.8ms so that the maximum time between >> two updates typically does not exceed 11ms. This roughly matches >> the 10ms period time when doing playback with the audio timer. >> After this patch the debug log looks like this. >> >> audio: Elapsed since last alsa run (running): 0.011919 >> audio: Elapsed since last alsa run (running): 0.005788 >> audio: Elapsed since last alsa run (running): 0.005995 >> audio: Elapsed since last alsa run (running): 0.011069 >> audio: Elapsed since last alsa run (running): 0.005901 >> audio: Elapsed since last alsa run (running): 0.006084 >> >> Acked-by: Christian Schoenebeck <qemu_oss@crudebyte.com> >> Signed-off-by: Volker Rümelin <vr_qemu@t-online.de> >> --- >> audio/alsaaudio.c | 11 ++++------- >> 1 file changed, 4 insertions(+), 7 deletions(-) >> >> diff --git a/audio/alsaaudio.c b/audio/alsaaudio.c >> index 5f50dfa0bf..0cc982e61f 100644 >> --- a/audio/alsaaudio.c >> +++ b/audio/alsaaudio.c >> @@ -913,17 +913,14 @@ static void *alsa_audio_init(Audiodev *dev) >> alsa_init_per_direction(aopts->in); >> alsa_init_per_direction(aopts->out); >> - /* >> - * need to define them, as otherwise alsa produces no sound >> - * doesn't set has_* so alsa_open can identify it wasn't set by >> the user >> - */ >> + /* don't set has_* so alsa_open can identify it wasn't set by >> the user */ >> if (!dev->u.alsa.out->has_period_length) { >> - /* 1024 frames assuming 44100Hz */ >> - dev->u.alsa.out->period_length = 1024 * 1000000 / 44100; >> + /* 256 frames assuming 44100Hz */ >> + dev->u.alsa.out->period_length = 5805; > > Please use DIV_ROUND_UP(): > > DIV_ROUND_UP(1000000ul << 8, 44100); > > Or > > DIV_ROUND_UP(512 * 1000000ul, 44100); Hi, the corresponding -audiodev alsa command line parameters out.buffer-length, in.buffer-length, out.period-length and in.period-lenght are specified in microseconds. I prefer that the default values use the same unit. I believe that specifying buffer lengths in microseconds makes more sense than specifying buffer lengths in audio frames. With best regards, Volker > > >> } >> if (!dev->u.alsa.out->has_buffer_length) { >> /* 4096 frames assuming 44100Hz */ >> - dev->u.alsa.out->buffer_length = 4096ll * 1000000 / 44100; >> + dev->u.alsa.out->buffer_length = 92880; > > Ditto: > > DIV_ROUND_UP(1000000ul << 12, 44100); > >> } >> /* >
diff --git a/audio/alsaaudio.c b/audio/alsaaudio.c index 5f50dfa0bf..0cc982e61f 100644 --- a/audio/alsaaudio.c +++ b/audio/alsaaudio.c @@ -913,17 +913,14 @@ static void *alsa_audio_init(Audiodev *dev) alsa_init_per_direction(aopts->in); alsa_init_per_direction(aopts->out); - /* - * need to define them, as otherwise alsa produces no sound - * doesn't set has_* so alsa_open can identify it wasn't set by the user - */ + /* don't set has_* so alsa_open can identify it wasn't set by the user */ if (!dev->u.alsa.out->has_period_length) { - /* 1024 frames assuming 44100Hz */ - dev->u.alsa.out->period_length = 1024 * 1000000 / 44100; + /* 256 frames assuming 44100Hz */ + dev->u.alsa.out->period_length = 5805; } if (!dev->u.alsa.out->has_buffer_length) { /* 4096 frames assuming 44100Hz */ - dev->u.alsa.out->buffer_length = 4096ll * 1000000 / 44100; + dev->u.alsa.out->buffer_length = 92880; } /*