auracaster/pyalsaaudio
3
0
Fork 1
mirror of https://github.com/larsimmisch/pyalsaaudio.git synced 2026-04-22 10:24:49 +00:00
Code Issues Packages Projects Releases Wiki Activity

make period count configurable

Browse Source 
the period count is just as important for playback latency as the period
size, so it makes no sense to have only one of them configurable.

as a drive-by, fix up the handling of periods in info() & dumpinfo().
This commit is contained in:
Oswald Buddenhagen
2022-08-06 17:44:15 +02:00
parent de2fc3c992
commit 17d171c1a5
2 changed files with 18 additions and 9 deletions
Download Patch File Download Diff File Expand all files Collapse all files

20
alsaaudio.c
View File

@@ -110,6 +110,7 @@ typedef struct {
unsigned int channels; unsigned int channels;
unsigned int rate; unsigned int rate;
snd_pcm_format_t format; snd_pcm_format_t format;
unsigned int periods;
snd_pcm_uframes_t periodsize; snd_pcm_uframes_t periodsize;
int framesize; int framesize;
@@ -384,11 +385,10 @@ static int alsapcm_setup(alsapcm_t *self)
self->channels); self->channels);
dir = 0; dir = 0;
unsigned int periods = 4;
snd_pcm_hw_params_set_rate_near(self->handle, hwparams, &self->rate, &dir); snd_pcm_hw_params_set_rate_near(self->handle, hwparams, &self->rate, &dir);
snd_pcm_hw_params_set_period_size_near(self->handle, hwparams, snd_pcm_hw_params_set_period_size_near(self->handle, hwparams,
&self->periodsize, &dir); &self->periodsize, &dir);
snd_pcm_hw_params_set_periods_near(self->handle, hwparams, &periods, &dir); snd_pcm_hw_params_set_periods_near(self->handle, hwparams, &self->periods, &dir);
/* Write it to the device */ /* Write it to the device */
res = snd_pcm_hw_params(self->handle, hwparams); res = snd_pcm_hw_params(self->handle, hwparams);
@@ -401,6 +401,7 @@ static int alsapcm_setup(alsapcm_t *self)
snd_pcm_hw_params_get_channels(hwparams, &self->channels); snd_pcm_hw_params_get_channels(hwparams, &self->channels);
snd_pcm_hw_params_get_rate(hwparams, &self->rate, &dir); snd_pcm_hw_params_get_rate(hwparams, &self->rate, &dir);
snd_pcm_hw_params_get_period_size(hwparams, &self->periodsize, &dir); snd_pcm_hw_params_get_period_size(hwparams, &self->periodsize, &dir);
snd_pcm_hw_params_get_periods(hwparams, &self->periods, &dir);
self->framesize = self->channels * snd_pcm_hw_params_get_sbits(hwparams)/8; self->framesize = self->channels * snd_pcm_hw_params_get_sbits(hwparams)/8;
@@ -422,13 +423,15 @@ alsapcm_new(PyTypeObject *type, PyObject *args, PyObject *kwds)
int rate = 44100; int rate = 44100;
int channels = 2; int channels = 2;
int format = SND_PCM_FORMAT_S16_LE; int format = SND_PCM_FORMAT_S16_LE;
int periods = 4;
int periodsize = 32; int periodsize = 32;
char *kw[] = { "type", "mode", "device", "cardindex", "card", "rate", "channels", "format", "periodsize", NULL }; char *kw[] = { "type", "mode", "device", "cardindex", "card",
"rate", "channels", "format", "periodsize", "periods", NULL };
if (!PyArg_ParseTupleAndKeywords(args, kwds, "|Oisiziiii", kw, if (!PyArg_ParseTupleAndKeywords(args, kwds, "|Oisiziiiii", kw,
&pcmtypeobj, &pcmmode, &device, &pcmtypeobj, &pcmmode, &device, &cardidx, &card,
&cardidx, &card, &rate, &channels, &format, &periodsize)) &rate, &channels, &format, &periodsize, &periods))
return NULL; return NULL;
if (cardidx >= 0) { if (cardidx >= 0) {
@@ -475,6 +478,7 @@ alsapcm_new(PyTypeObject *type, PyObject *args, PyObject *kwds)
self->channels = channels; self->channels = channels;
self->rate = rate; self->rate = rate;
self->format = format; self->format = format;
self->periods = periods;
self->periodsize = periodsize; self->periodsize = periodsize;
res = snd_pcm_open(&(self->handle), device, self->pcmtype, res = snd_pcm_open(&(self->handle), device, self->pcmtype,
@@ -586,7 +590,7 @@ alsapcm_dumpinfo(alsapcm_t *self, PyObject *args)
printf("buffer size = %d frames\n", (int)frames); printf("buffer size = %d frames\n", (int)frames);
snd_pcm_hw_params_get_periods(hwparams, &val, &dir); snd_pcm_hw_params_get_periods(hwparams, &val, &dir);
printf("periods per buffer = %d frames\n", val); printf("periods per buffer = %d\n", val);
snd_pcm_hw_params_get_rate_numden(hwparams, &val, &val2); snd_pcm_hw_params_get_rate_numden(hwparams, &val, &val2);
printf("exact rate = %d/%d bps\n", val, val2); printf("exact rate = %d/%d bps\n", val, val2);
@@ -760,7 +764,7 @@ alsapcm_info(alsapcm_t *self, PyObject *args)
snd_pcm_hw_params_get_periods(hwparams, &val, &dir); snd_pcm_hw_params_get_periods(hwparams, &val, &dir);
value=PyLong_FromUnsignedLong((unsigned long) val); value=PyLong_FromUnsignedLong((unsigned long) val);
PyDict_SetItemString(info,"get_periods", value); PyDict_SetItemString(info,"periods", value);
Py_DECREF(value); Py_DECREF(value);
snd_pcm_hw_params_get_rate_numden(hwparams, &val, &val2); snd_pcm_hw_params_get_rate_numden(hwparams, &val, &val2);

7
doc/libalsaaudio.rst
View File

@@ -96,7 +96,7 @@ PCM objects in :mod:`alsaaudio` can play or capture (record) PCM
sound through speakers or a microphone. The PCM constructor takes the sound through speakers or a microphone. The PCM constructor takes the
following arguments: following arguments:
.. class:: PCM(type=PCM_PLAYBACK, mode=PCM_NORMAL, rate=44100, channels=2, format=PCM_FORMAT_S16_LE, periodsize=32, device='default', cardindex=-1) .. class:: PCM(type=PCM_PLAYBACK, mode=PCM_NORMAL, rate=44100, channels=2, format=PCM_FORMAT_S16_LE, periodsize=32, periods=4, device='default', cardindex=-1)
This class is used to represent a PCM device (either for playback and This class is used to represent a PCM device (either for playback and
recording). The arguments are: recording). The arguments are:
@@ -146,6 +146,7 @@ following arguments:
Make sure you understand :ref:`the meaning of periods <term-period>`. Make sure you understand :ref:`the meaning of periods <term-period>`.
The default value is 32, which is below the actual minimum of most devices, The default value is 32, which is below the actual minimum of most devices,
and will therefore likely be larger in practice. and will therefore likely be larger in practice.
* *periods* - the number of periods in the buffer. The default value is 4.
* *device* - the name of the PCM device that should be used (for example * *device* - the name of the PCM device that should be used (for example
a value from the output of :func:`pcms`). The default value is a value from the output of :func:`pcms`). The default value is
``'default'``. ``'default'``.
@@ -158,6 +159,10 @@ following arguments:
This will construct a PCM object with the given settings. This will construct a PCM object with the given settings.
*Changed in 0.10:*
- Added the optional named parameter `periods`.
*Changed in 0.9:* *Changed in 0.9:*
- Added the optional named parameters `rate`, `channels`, `format` and `periodsize`. - Added the optional named parameters `rate`, `channels`, `format` and `periodsize`.