ref: 7e6e33818acc4623d440ed1d6371760cf84d6ad3
dir: /src/alsa.c/
/* ALSA sound handler
*
* Copyright 1997-2005 Jimen Ching And Sundry Contributors
* This source code is freely redistributable and may be used for
* any purpose. This copyright notice must be maintained.
* Jimen Ching And Sundry Contributors are not
* responsible for the consequences of using this software.
*/
#include "sox_i.h"
#include <alsa/asoundlib.h>
typedef struct alsa_priv
{
snd_pcm_t *pcm_handle;
char *buf;
sox_size_t buf_size;
snd_pcm_uframes_t period_size;
snd_pcm_uframes_t frames_this_period;
} *alsa_priv_t;
static int get_format(sox_format_t * ft, snd_pcm_format_mask_t *fmask, int *fmt)
{
if (ft->encoding.bits_per_sample != 16)
{
sox_report("trying for word samples.");
ft->encoding.bits_per_sample = 16;
}
if (ft->encoding.encoding != SOX_ENCODING_SIGN2 &&
ft->encoding.encoding != SOX_ENCODING_UNSIGNED)
{
if (ft->encoding.bits_per_sample == 16)
{
if (ft->encoding.encoding != SOX_ENCODING_UNKNOWN)
sox_report("driver supports only signed and unsigned samples. Changing to signed.");
ft->encoding.encoding = SOX_ENCODING_SIGN2;
}
else
{
if (ft->encoding.encoding != SOX_ENCODING_UNKNOWN)
sox_report("driver supports only signed and unsigned samples. Changing to unsigned.");
ft->encoding.encoding = SOX_ENCODING_UNSIGNED;
}
}
/* Some hardware only wants to work with 8-bit or 16-bit data */
if (ft->encoding.bits_per_sample == 8)
{
if (!(snd_pcm_format_mask_test(fmask, SND_PCM_FORMAT_U8)) &&
!(snd_pcm_format_mask_test(fmask, SND_PCM_FORMAT_S8)))
{
sox_report("driver doesn't supported byte samples. Changing to words.");
ft->encoding.bits_per_sample = 16;
}
}
else if (ft->encoding.bits_per_sample == 16)
{
if (!(snd_pcm_format_mask_test(fmask, SND_PCM_FORMAT_U16)) &&
!(snd_pcm_format_mask_test(fmask, SND_PCM_FORMAT_S16)))
{
sox_report("driver doesn't supported word samples. Changing to bytes.");
ft->encoding.bits_per_sample = 8;
}
}
else
{
if ((snd_pcm_format_mask_test(fmask, SND_PCM_FORMAT_U16)) ||
(snd_pcm_format_mask_test(fmask, SND_PCM_FORMAT_S16)))
{
sox_report("driver doesn't supported %u-bit samples. Changing to 16-bit.", ft->encoding.bits_per_sample);
ft->encoding.bits_per_sample = 16;
}
else
{
sox_report("driver doesn't supported %u-bit samples. Changing to 8-bit.", ft->encoding.bits_per_sample);
ft->encoding.bits_per_sample = 8;
}
}
if (ft->encoding.bits_per_sample == 8) {
switch (ft->encoding.encoding)
{
case SOX_ENCODING_SIGN2:
if (!(snd_pcm_format_mask_test(fmask, SND_PCM_FORMAT_S8)))
{
sox_report("driver doesn't supported signed byte samples. Changing to unsigned bytes.");
ft->encoding.encoding = SOX_ENCODING_UNSIGNED;
}
break;
case SOX_ENCODING_UNSIGNED:
if (!(snd_pcm_format_mask_test(fmask, SND_PCM_FORMAT_U8)))
{
sox_report("driver doesn't supported unsigned byte samples. Changing to signed bytes.");
ft->encoding.encoding = SOX_ENCODING_SIGN2;
}
break;
default:
break;
}
switch (ft->encoding.encoding)
{
case SOX_ENCODING_SIGN2:
if (!(snd_pcm_format_mask_test(fmask, SND_PCM_FORMAT_S8)))
{
sox_fail_errno(ft,SOX_EFMT,"ALSA driver does not support signed byte samples");
return SOX_EOF;
}
*fmt = SND_PCM_FORMAT_S8;
break;
case SOX_ENCODING_UNSIGNED:
if (!(snd_pcm_format_mask_test(fmask, SND_PCM_FORMAT_U8)))
{
sox_fail_errno(ft,SOX_EFMT,"ALSA driver does not support unsigned byte samples");
return SOX_EOF;
}
*fmt = SND_PCM_FORMAT_U8;
break;
default:
break;
}
}
else if (ft->encoding.bits_per_sample == 16) {
switch (ft->encoding.encoding)
{
case SOX_ENCODING_SIGN2:
if (!(snd_pcm_format_mask_test(fmask, SND_PCM_FORMAT_S16)))
{
sox_report("driver does not support signed word samples. Changing to unsigned words.");
ft->encoding.encoding = SOX_ENCODING_UNSIGNED;
}
break;
case SOX_ENCODING_UNSIGNED:
if (!(snd_pcm_format_mask_test(fmask, SND_PCM_FORMAT_U16)))
{
sox_report("driver does not support unsigned word samples. Changing to signed words.");
ft->encoding.encoding = SOX_ENCODING_SIGN2;
}
break;
default:
break;
}
switch (ft->encoding.encoding)
{
case SOX_ENCODING_SIGN2:
if (!(snd_pcm_format_mask_test(fmask, SND_PCM_FORMAT_S16)))
{
sox_fail_errno(ft,SOX_EFMT,"ALSA driver does not support signed word samples");
return SOX_EOF;
}
*fmt = SND_PCM_FORMAT_S16;
break;
case SOX_ENCODING_UNSIGNED:
if (!(snd_pcm_format_mask_test(fmask, SND_PCM_FORMAT_U16)))
{
sox_fail_errno(ft,SOX_EFMT,"ALSA driver does not support unsigned word samples");
return SOX_EOF;
}
*fmt = SND_PCM_FORMAT_U16;
break;
default:
break;
}
}
else {
sox_fail_errno(ft,SOX_EFMT,"ALSA driver does not support %s %u-bit output",
sox_encodings_str[(unsigned char)ft->encoding.encoding], ft->encoding.bits_per_sample);
return SOX_EOF;
}
return 0;
}
static int setup(sox_format_t * ft, snd_pcm_stream_t mode)
{
int fmt = SND_PCM_FORMAT_S16;
int err;
alsa_priv_t alsa = (alsa_priv_t)ft->priv;
snd_pcm_hw_params_t *hw_params = NULL;
unsigned int min_rate, max_rate;
unsigned int min_chan, max_chan;
unsigned int rate;
snd_pcm_uframes_t buffer_size, buffer_size_min, buffer_size_max;
snd_pcm_uframes_t period_size, period_size_min, period_size_max;
int dir;
snd_pcm_format_mask_t *fmask = NULL;
sox_signalinfo_t client_signal = ft->signal;
set_signal_defaults(&ft->signal);
if ((err = snd_pcm_open(&(alsa->pcm_handle), ft->filename,
mode, 0)) < 0)
{
sox_fail_errno(ft, SOX_EPERM, "cannot open audio device");
goto open_error;
}
if ((err = snd_pcm_hw_params_malloc(&hw_params)) < 0)
{
sox_fail_errno(ft, SOX_ENOMEM,
"cannot allocate hardware parameter structure");
goto open_error;
}
if ((err = snd_pcm_hw_params_any(alsa->pcm_handle, hw_params)) < 0)
{
sox_fail_errno(ft, SOX_EPERM,
"cannot initialize hardware parameter structure");
goto open_error;
}
#if SND_LIB_VERSION >= 0x010009
/* Turn off software resampling */
err = snd_pcm_hw_params_set_rate_resample(alsa->pcm_handle, hw_params, 0);
if (err < 0) {
sox_fail_errno(ft, SOX_EPERM, "Resampling setup failed for playback");
goto open_error;
}
#endif
if ((err = snd_pcm_hw_params_set_access(alsa->pcm_handle, hw_params,
SND_PCM_ACCESS_RW_INTERLEAVED)) < 0)
{
sox_fail_errno(ft, SOX_EPERM,
"cannot set access type");
goto open_error;
}
snd_pcm_hw_params_get_channels_min(hw_params, &min_chan);
snd_pcm_hw_params_get_channels_max(hw_params, &max_chan);
if (ft->signal.channels == 0)
ft->signal.channels = min_chan;
else
if (ft->signal.channels > max_chan)
ft->signal.channels = max_chan;
else if (ft->signal.channels < min_chan)
ft->signal.channels = min_chan;
if (snd_pcm_format_mask_malloc(&fmask) < 0)
goto open_error;
snd_pcm_hw_params_get_format_mask(hw_params, fmask);
if (get_format(ft, fmask, &fmt) < 0)
goto open_error;
snd_pcm_format_mask_free(fmask);
fmask = NULL;
if ((err = snd_pcm_hw_params_set_format(alsa->pcm_handle,
hw_params, fmt)) < 0)
{
sox_fail_errno(ft, SOX_EPERM, "cannot set sample format");
goto open_error;
}
snd_pcm_hw_params_get_rate_min(hw_params, &min_rate, &dir);
snd_pcm_hw_params_get_rate_max(hw_params, &max_rate, &dir);
rate = range_limit(ft->signal.rate, min_rate, max_rate);
if (rate != ft->signal.rate)
{
if (client_signal.rate != 0)
sox_report("hardware does not support sample rate %g; changing to %i.", ft->signal.rate, rate);
ft->signal.rate = rate;
}
dir = 0;
if ((err = snd_pcm_hw_params_set_rate_near(alsa->pcm_handle,
hw_params,
&rate,
&dir)) < 0)
{
sox_fail_errno(ft, SOX_EPERM, "cannot set sample rate");
goto open_error;
}
snd_pcm_hw_params_get_rate(hw_params,
&rate,
&dir);
if (rate != ft->signal.rate)
{
sox_report("Could not set exact rate of %g. Approximating with %i",
ft->signal.rate, rate);
}
snd_pcm_hw_params_get_rate(hw_params, &rate, &dir);
if ((err = snd_pcm_hw_params_set_channels(alsa->pcm_handle,
hw_params,
ft->signal.channels)) < 0)
{
sox_fail_errno(ft, SOX_EPERM, "cannot set channel count");
goto open_error;
}
/* Have a much larger buffer than sox_globals.bufsiz to avoid underruns */
buffer_size = sox_globals.bufsiz * 8 / (ft->encoding.bits_per_sample >> 3) / ft->signal.channels;
if (snd_pcm_hw_params_get_buffer_size_min(hw_params, &buffer_size_min) < 0)
{
sox_fail_errno(ft, SOX_EPERM, "Error getting min buffer size.");
goto open_error;
}
if (snd_pcm_hw_params_get_buffer_size_max(hw_params, &buffer_size_max) < 0)
{
sox_fail_errno(ft, SOX_EPERM, "Error getting max buffer size.");
goto open_error;
}
dir = 0;
if (snd_pcm_hw_params_get_period_size_min(hw_params,
&period_size_min, &dir) < 0)
{
sox_fail_errno(ft, SOX_EPERM, "Error getting min period size.");
goto open_error;
}
dir = 0;
if (snd_pcm_hw_params_get_period_size_max(hw_params,
&period_size_max, &dir) < 0)
{
sox_fail_errno(ft, SOX_EPERM, "Error getting max buffer size.");
goto open_error;
}
if (buffer_size_max < buffer_size)
buffer_size = buffer_size_max;
else if (buffer_size_min > buffer_size)
buffer_size = buffer_size_min;
period_size = buffer_size / 8;
buffer_size = period_size * 8;
dir = 0;
if (snd_pcm_hw_params_set_period_size_near(alsa->pcm_handle, hw_params,
&period_size, &dir) < 0)
{
sox_fail_errno(ft, SOX_EPERM, "Error setting periods.");
goto open_error;
}
snd_pcm_hw_params_get_period_size(hw_params, &period_size, &dir);
dir = 0;
if (snd_pcm_hw_params_set_buffer_size_near(alsa->pcm_handle, hw_params,
&buffer_size) < 0) {
sox_fail_errno(ft, SOX_EPERM, "Error setting buffer size.");
goto open_error;
}
snd_pcm_hw_params_get_buffer_size(hw_params, &buffer_size);
if (period_size * 2 > buffer_size)
{
sox_fail_errno(ft, SOX_EPERM, "Buffer too small. Could not use.");
goto open_error;
}
if ((err = snd_pcm_hw_params(alsa->pcm_handle, hw_params)) < 0)
{
sox_fail_errno(ft, SOX_EPERM, "cannot set parameters");
goto open_error;
}
snd_pcm_hw_params_free(hw_params);
hw_params = NULL;
if ((err = snd_pcm_prepare(alsa->pcm_handle)) < 0)
{
sox_fail_errno(ft, SOX_EPERM, "cannot prepare audio interface for use");
goto open_error;
}
alsa->buf_size = buffer_size * (ft->encoding.bits_per_sample >> 3) * ft->signal.channels;
alsa->period_size = period_size;
alsa->frames_this_period = 0;
alsa->buf = xmalloc(alsa->buf_size);
return (SOX_SUCCESS);
open_error:
if (fmask)
snd_pcm_format_mask_free(fmask);
if (hw_params)
snd_pcm_hw_params_free(hw_params);
return SOX_EOF;
}
/*
* Over/underrun and suspend recovery
*/
static int xrun_recovery(snd_pcm_t *handle, int err)
{
if (err == -EPIPE)
{ /* over/under-run */
err = snd_pcm_prepare(handle);
if (err < 0)
sox_warn("Can't recover from over/underrun, prepare failed: %s", snd_strerror(err));
return 0;
}
else
{
if (err == -ESTRPIPE)
{
/* wait until the suspend flag is released */
while ((err = snd_pcm_resume(handle)) == -EAGAIN)
sleep(1);
if (err < 0)
{
err = snd_pcm_prepare(handle);
if (err < 0)
sox_warn("Can't recovery from suspend, prepare failed: %s", snd_strerror(err));
}
}
return 0;
}
return err;
}
/*
* Do anything required before you start reading samples.
* Read file header.
* Find out sampling rate,
* size and encoding of samples,
* mono/stereo/quad.
*/
static int startread(sox_format_t * ft)
{
return setup(ft, SND_PCM_STREAM_CAPTURE);
}
static void ub_read_buf(sox_sample_t *buf1, char const * buf2, sox_size_t len, sox_bool swap UNUSED, sox_size_t * clips UNUSED)
{
while (len--)
*buf1++ = SOX_UNSIGNED_8BIT_TO_SAMPLE(*((unsigned char *)buf2++),);
}
static void sb_read_buf(sox_sample_t *buf1, char const * buf2, sox_size_t len, sox_bool swap UNUSED, sox_size_t * clips UNUSED)
{
while (len--)
*buf1++ = SOX_SIGNED_8BIT_TO_SAMPLE(*((int8_t *)buf2++),);
}
static void uw_read_buf(sox_sample_t *buf1, char const * buf2, sox_size_t len, sox_bool swap, sox_size_t * clips UNUSED)
{
while (len--)
{
uint16_t datum = *((uint16_t *)buf2);
buf2++; buf2++;
if (swap)
datum = sox_swapw(datum);
*buf1++ = SOX_UNSIGNED_16BIT_TO_SAMPLE(datum,);
}
}
static void sw_read_buf(sox_sample_t *buf1, char const * buf2, sox_size_t len, sox_bool swap, sox_size_t * clips UNUSED)
{
while (len--)
{
int16_t datum = *((int16_t *)buf2);
buf2++; buf2++;
if (swap)
datum = sox_swapw(datum);
*buf1++ = SOX_SIGNED_16BIT_TO_SAMPLE(datum,);
}
}
static sox_size_t read_samples(sox_format_t * ft, sox_sample_t *buf, sox_size_t nsamp)
{
alsa_priv_t alsa = (alsa_priv_t)ft->priv;
void (*read_buf)(sox_sample_t *, char const *, sox_size_t, sox_bool, sox_size_t *) = 0;
sox_size_t len;
switch(ft->encoding.bits_per_sample) {
case 8:
switch(ft->encoding.encoding) {
case SOX_ENCODING_SIGN2: read_buf = sb_read_buf; break;
case SOX_ENCODING_UNSIGNED: read_buf = ub_read_buf; break;
default:
sox_fail_errno(ft,SOX_EFMT,"Do not support this encoding for this data size");
return 0;
}
break;
case 16:
switch(ft->encoding.encoding) {
case SOX_ENCODING_SIGN2: read_buf = sw_read_buf; break;
case SOX_ENCODING_UNSIGNED: read_buf = uw_read_buf; break;
default:
sox_fail_errno(ft,SOX_EFMT,"Do not support this encoding for this data size");
return 0;
}
break;
default:
sox_fail_errno(ft,SOX_EFMT,"Do not support this data size for this handler");
return 0;
}
/* Prevent overflow */
if (nsamp > alsa->buf_size/(ft->encoding.bits_per_sample >> 3))
nsamp = (alsa->buf_size/(ft->encoding.bits_per_sample >> 3));
len = 0;
while (len < nsamp) {
sox_size_t n = snd_pcm_readi(alsa->pcm_handle, alsa->buf,
(nsamp - len)/ft->signal.channels); /* ALSA takes "frame" counts. */
if ((int)n < 0) {
if (xrun_recovery(alsa->pcm_handle, (int)n) < 0) {
sox_fail_errno(ft, SOX_EPERM, "ALSA read error");
return 0;
}
} else {
n *= ft->signal.channels;
read_buf(buf + len, alsa->buf, n, ft->encoding.reverse_bytes, &ft->clips);
len += n;
}
}
return len;
}
static int stopread(sox_format_t * ft)
{
alsa_priv_t alsa = (alsa_priv_t)ft->priv;
snd_pcm_close(alsa->pcm_handle);
free(alsa->buf);
return SOX_SUCCESS;
}
static int startwrite(sox_format_t * ft)
{
return setup(ft, SND_PCM_STREAM_PLAYBACK);
}
static void sox_ub_write_buf(char* buf1, sox_sample_t const * buf2, sox_size_t len, sox_bool swap UNUSED, sox_size_t * clips)
{
while (len--)
*(uint8_t *)buf1++ = SOX_SAMPLE_TO_UNSIGNED_8BIT(*buf2++, *clips);
}
static void sox_sb_write_buf(char *buf1, sox_sample_t const * buf2, sox_size_t len, sox_bool swap UNUSED, sox_size_t * clips)
{
while (len--)
*(int8_t *)buf1++ = SOX_SAMPLE_TO_SIGNED_8BIT(*buf2++, *clips);
}
static void sox_uw_write_buf(char *buf1, sox_sample_t const * buf2, sox_size_t len, sox_bool swap, sox_size_t * clips)
{
while (len--)
{
uint16_t datum = SOX_SAMPLE_TO_UNSIGNED_16BIT(*buf2++, *clips);
if (swap)
datum = sox_swapw(datum);
*(uint16_t *)buf1 = datum;
buf1++; buf1++;
}
}
static void sox_sw_write_buf(char *buf1, sox_sample_t const * buf2, sox_size_t len, sox_bool swap, sox_size_t * clips)
{
while (len--)
{
int16_t datum = SOX_SAMPLE_TO_SIGNED_16BIT(*buf2++, *clips);
if (swap)
datum = sox_swapw(datum);
*(int16_t *)buf1 = datum;
buf1++; buf1++;
}
}
static sox_size_t write_samples(sox_format_t * ft, const sox_sample_t *buf, sox_size_t nsamp)
{
sox_size_t osamp, done;
alsa_priv_t alsa = (alsa_priv_t)ft->priv;
void (*write_buf)(char *, const sox_sample_t *, sox_size_t, sox_bool, sox_size_t *) = 0;
switch(ft->encoding.bits_per_sample) {
case 8:
switch (ft->encoding.encoding)
{
case SOX_ENCODING_SIGN2:
write_buf = sox_sb_write_buf;
break;
case SOX_ENCODING_UNSIGNED:
write_buf = sox_ub_write_buf;
break;
default:
sox_fail_errno(ft,SOX_EFMT,"this encoding is not supported for this data size");
return 0;
}
break;
case 16:
switch (ft->encoding.encoding)
{
case SOX_ENCODING_SIGN2:
write_buf = sox_sw_write_buf;
break;
case SOX_ENCODING_UNSIGNED:
write_buf = sox_uw_write_buf;
break;
default:
sox_fail_errno(ft,SOX_EFMT,"this encoding is not supported for this data size");
return 0;
}
break;
default:
sox_fail_errno(ft,SOX_EFMT,"this data size is not supported by this handler");
return 0;
}
for (done = 0; done < nsamp; done += osamp) {
int err;
sox_size_t len;
osamp = min(nsamp - done, alsa->buf_size / (ft->encoding.bits_per_sample >> 3));
write_buf(alsa->buf, buf, osamp, ft->encoding.reverse_bytes, &ft->clips);
buf += osamp;
for (len = 0; len < osamp;) {
err = snd_pcm_writei(alsa->pcm_handle,
alsa->buf + (len * (ft->encoding.bits_per_sample >> 3)),
(osamp - len) / ft->signal.channels);
if (errno == EAGAIN) /* Happens naturally; don't report it */
errno = 0;
if (err < 0) {
if (xrun_recovery(alsa->pcm_handle, err) < 0) {
sox_fail_errno(ft, SOX_EPERM, "ALSA write error");
return 0;
}
} else
len += err * ft->signal.channels;
}
}
/* keep track of how many frames have been played this period, so we know
* how many frames of silence to append at the end of playback */
alsa->frames_this_period = (alsa->frames_this_period + nsamp / ft->signal.channels) % alsa->period_size;
return nsamp;
}
static int stopwrite(sox_format_t * ft)
{
alsa_priv_t alsa = (alsa_priv_t)ft->priv;
/* Pad to hardware period: */
sox_size_t npad = (alsa->period_size - alsa->frames_this_period) * ft->signal.channels;
sox_sample_t * buf = xcalloc(npad, sizeof(*buf)); /* silent samples */
write_samples(ft, buf, npad);
free(buf);
snd_pcm_drain(alsa->pcm_handle);
snd_pcm_close(alsa->pcm_handle);
free(alsa->buf);
return SOX_SUCCESS;
}
SOX_FORMAT_HANDLER(alsa)
{
static char const * const names[] = { "alsa", NULL };
static unsigned const write_encodings[] = {
SOX_ENCODING_SIGN2, 16, 8, 0,
SOX_ENCODING_UNSIGNED, 16, 8, 0,
0};
static sox_format_handler_t const handler = {
SOX_LIB_VERSION_CODE,
"Advanced Linux Sound Architecture device driver",
names, SOX_FILE_DEVICE | SOX_FILE_NOSTDIO,
startread, read_samples, stopread,
startwrite, write_samples, stopwrite,
NULL, write_encodings, NULL
};
return &handler;
}