ref: c6b7f738caa13c26ed423d21f3246a60fd35075a
dir: /src/alsa.c/
/*
* 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.
*/
/* ALSA sound driver
*
* converted to alsalib cbagwell 20050914
* added by Jimen Ching (jching@flex.com) 19990207
* based on info grabed from aplay.c in alsa-utils package.
* Updated for ALSA 0.9.X API 20020824.
*/
#include "st_i.h"
#if defined(HAVE_ALSA)
#include <alsa/asoundlib.h>
typedef struct alsa_priv
{
snd_pcm_t *pcm_handle;
void *buf;
st_ssize_t buf_size;
} *alsa_priv_t;
static int get_format(ft_t ft, snd_pcm_format_mask_t *fmask, int *fmt);
extern void st_ub_write_buf(char* buf1, st_sample_t *buf2, st_ssize_t len, char swap);
extern void st_sb_write_buf(char *buf1, st_sample_t *buf2, st_ssize_t len, char swap);
extern void st_uw_write_buf(char *buf1, st_sample_t *buf2, st_ssize_t len, char swap);
extern void st_sw_write_buf(char *buf1, st_sample_t *buf2, st_ssize_t len, char swap);
extern void st_ub_read_buf(st_sample_t *buf1, char *buf2, st_ssize_t len, char swap);
extern void st_sb_read_buf(st_sample_t *buf1, char *buf2, st_ssize_t len, char swap);
extern void st_uw_read_buf(st_sample_t *buf1, char *buf2, st_ssize_t len, char swap);
extern void st_sw_read_buf(st_sample_t *buf1, char *buf2, st_ssize_t len, char swap);
int st_alsasetup(ft_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;
snd_pcm_sw_params_t *sw_params;
unsigned int min_rate, max_rate;
unsigned int min_chan, max_chan;
unsigned int rate, periods;
snd_pcm_uframes_t buffer_size;
int dir;
snd_pcm_format_mask_t *fmask;
#if 0
unsigned int buffer_time = 500000;
unsigned int period_time = 100000;
snd_pcm_sframes_t period_size;
#endif
/* Reserve buffer for 16-bit data. FIXME: Whats a good size? */
alsa->buf_size = ST_BUFSIZ*2;
if ((alsa->buf = malloc(alsa->buf_size)) == NULL)
{
st_fail_errno(ft,ST_ENOMEM,
"unable to allocate output buffer of size %d",
ft->file.size);
return(ST_EOF);
}
if ((err = snd_pcm_open(&(alsa->pcm_handle), ft->filename,
mode, 0)) < 0)
{
st_fail_errno(ft, ST_EPERM, "cannot open audio device");
return ST_EOF;
}
if ((err = snd_pcm_hw_params_malloc(&hw_params)) < 0)
{
st_fail_errno(ft, ST_ENOMEM,
"cannot allocate hardware parameter structure");
return ST_EOF;
}
if ((err = snd_pcm_hw_params_any(alsa->pcm_handle, hw_params)) < 0)
{
st_fail_errno(ft, ST_EPERM,
"cannot initialize hardware parameter structure");
return ST_EOF;
}
/* set hardware resampling */
rate = 0;
err = snd_pcm_hw_params_set_rate_resample(alsa->pcm_handle, hw_params,
rate);
if (err < 0) {
st_fail_errno(ft, ST_EPERM, "Resampling setup failed for playback");
return ST_EOF;
}
if ((err = snd_pcm_hw_params_set_access(alsa->pcm_handle, hw_params,
SND_PCM_ACCESS_RW_INTERLEAVED)) < 0)
{
st_fail_errno(ft, ST_EPERM,
"cannot set access type");
return ST_EOF;
}
snd_pcm_hw_params_get_channels_min(hw_params, &min_chan);
snd_pcm_hw_params_get_channels_max(hw_params, &max_chan);
if (ft->info.channels == -1)
ft->info.channels = min_chan;
else
if (ft->info.channels > max_chan)
ft->info.channels = max_chan;
else if (ft->info.channels < min_chan)
ft->info.channels = min_chan;
snd_pcm_format_mask_malloc(&fmask);
snd_pcm_hw_params_get_format_mask(hw_params, fmask);
if (get_format(ft, fmask, &fmt) < 0)
return (ST_EOF);
snd_pcm_format_mask_free(fmask);
if ((err = snd_pcm_hw_params_set_format(alsa->pcm_handle,
hw_params, fmt)) < 0)
{
st_fail_errno(ft, ST_EPERM, "cannot set sample format");
return ST_EOF;
}
rate = ft->info.rate;
snd_pcm_hw_params_get_rate_min(hw_params, &min_rate, &dir);
snd_pcm_hw_params_get_rate_max(hw_params, &max_rate, &dir);
if (rate < min_rate)
rate = min_rate;
else
if (rate > max_rate)
rate = max_rate;
if (rate != ft->info.rate)
{
st_report("alsa: Hardware does not support %d. Forcing sample rate to %d.", ft->info.rate, rate);
ft->info.rate = rate;
}
dir = 0;
if ((err = snd_pcm_hw_params_set_rate_near(alsa->pcm_handle,
hw_params,
&rate,
&dir)) < 0)
{
st_fail_errno(ft, ST_EPERM, "cannot set sample rate");
return ST_EOF;
}
snd_pcm_hw_params_get_rate(hw_params,
&rate,
&dir);
if (rate != ft->info.rate)
{
st_report("Could not set exact rate of %d. Approximating with %d",
ft->info.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->info.channels)) < 0)
{
st_fail_errno(ft, ST_EPERM, "cannot set channel count");
return ST_EOF;
}
#if 0
/* set the buffer time */
err = snd_pcm_hw_params_set_buffer_time_near(alsa->pcm_handle, hw_params, &buffer_time, &dir);
if (err < 0) {
printf("Unable to set buffer time %i for playback: %s\n", buffer_time, snd_strerror(err));
return err;
}
err = snd_pcm_hw_params_get_buffer_size(hw_params, &buffer_size);
if (err < 0) {
printf("Unable to get buffer size for playback: %s\n", snd_strerror(err));
return err;
}
/* set the period time */
err = snd_pcm_hw_params_set_period_time_near(alsa->pcm_handle, hw_params, &period_time, &dir);
if (err < 0) {
printf("Unable to set period time %i for playback: %s\n", period_time, snd_strerror(err));
return err;
}
err = snd_pcm_hw_params_get_period_size(hw_params, &period_size, &dir);
if (err < 0) {
printf("Unable to get period size for playback: %s\n", snd_strerror(err));
return err;
}
#endif
#if 1
/* Set number of periods. Periods used to be called fragments. */
periods = 2;
if (snd_pcm_hw_params_set_periods_near(alsa->pcm_handle, hw_params,
&periods, &dir) < 0)
{
st_fail_errno(ft, ST_EPERM, "Error setting periods.");
return ST_EOF;
}
snd_pcm_hw_params_get_periods(hw_params, &periods, &dir);
/* Set buffer size (in frames). The resulting latency is given by */
/* latency = periodsize * periods / (rate * bytes_per_frame) */
buffer_size = ((ST_BUFSIZ/ft->info.size/ft->info.channels) * periods);
if (snd_pcm_hw_params_set_buffer_size_near(alsa->pcm_handle, hw_params,
&buffer_size) < 0) {
st_fail_errno(ft, ST_EPERM, "Error setting buffersize.");
return ST_EOF;
}
#endif
if ((err = snd_pcm_hw_params(alsa->pcm_handle, hw_params)) < 0)
{
st_fail_errno(ft, ST_EPERM, "cannot set parameters");
return ST_EOF;
}
snd_pcm_hw_params_free(hw_params);
if ((err = snd_pcm_sw_params_malloc(&sw_params)) < 0)
{
st_fail_errno(ft, ST_ENOMEM,
"cannot allocate software parameter structure");
return ST_EOF;
}
#if 0
/* get the current swparams */
err = snd_pcm_sw_params_current(alsa->pcm_handle, sw_params);
if (err < 0) {
printf("Unable to determine current swparams for playback: %s\n", snd_strerror(err));
return err;
}
/* start the transfer when the buffer is almost full: */
/* (buffer_size / avail_min) * avail_min */
err = snd_pcm_sw_params_set_start_threshold(alsa->pcm_handle, sw_params,
(buffer_size / period_size) * period_size);
if (err < 0) {
printf("Unable to set start threshold mode for playback: %s\n",
snd_strerror(err));
return err;
}
/* allow the transfer when at least period_size samples can be processed */
err = snd_pcm_sw_params_set_avail_min(alsa->pcm_handle, sw_params, period_size);
if (err < 0) {
printf("Unable to set avail min for playback: %s\n", snd_strerror(err));
return err;
}
/* align all transfers to 1 sample */
err = snd_pcm_sw_params_set_xfer_align(alsa->pcm_handle, sw_params, 1);
if (err < 0) {
printf("Unable to set transfer align for playback: %s\n", snd_strerror(err));
return err;
}
/* write the parameters to the playback device */
err = snd_pcm_sw_params(alsa->pcm_handle, sw_params);
if (err < 0) {
printf("Unable to set sw params for playback: %s\n", snd_strerror(err));
return err;
}
#endif
snd_pcm_sw_params_free(sw_params);
if ((err = snd_pcm_prepare(alsa->pcm_handle)) < 0)
{
st_fail_errno(ft, ST_EPERM, "cannot prepare audio interface for use");
return ST_EOF;
}
return (ST_SUCCESS);
}
/*
* Underrun and suspend recovery
*/
static int xrun_recovery(snd_pcm_t *handle, int err)
{
if (err == -EPIPE)
{ /* under-run */
err = snd_pcm_prepare(handle);
if (err < 0)
st_warn("Can't recovery from overrun, 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)
st_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.
*/
int st_alsastartread(ft_t ft)
{
return st_alsasetup(ft, SND_PCM_STREAM_CAPTURE);
}
st_ssize_t st_alsaread(ft_t ft, st_sample_t *buf, st_ssize_t nsamp)
{
st_ssize_t len;
int err;
alsa_priv_t alsa = (alsa_priv_t)ft->priv;
void (*read_buf)(st_sample_t *, char *, st_ssize_t, char) = 0;
switch(ft->info.size) {
case ST_SIZE_BYTE:
switch(ft->info.encoding)
{
case ST_ENCODING_SIGN2:
read_buf = st_sb_read_buf;
break;
case ST_ENCODING_UNSIGNED:
read_buf = st_ub_read_buf;
break;
default:
st_fail_errno(ft,ST_EFMT,"Do not support this encoding for this data size");
return ST_EOF;
}
break;
case ST_SIZE_WORD:
switch(ft->info.encoding)
{
case ST_ENCODING_SIGN2:
read_buf = st_sw_read_buf;
break;
case ST_ENCODING_UNSIGNED:
read_buf = st_uw_read_buf;
break;
default:
st_fail_errno(ft,ST_EFMT,"Do not support this encoding for this data size");
return ST_EOF;
}
break;
default:
st_fail_errno(ft,ST_EFMT,"Do not support this data size for this handler");
return ST_EOF;
}
/* Prevent overflow */
if (nsamp > alsa->buf_size/ft->info.size)
nsamp = (alsa->buf_size/ft->info.size);
len = 0;
while (len < nsamp)
{
/* ALSA library takes "frame" counts. */
err = snd_pcm_readi(alsa->pcm_handle, alsa->buf,
(nsamp-len)/ft->info.channels);
if (err == -EAGAIN)
continue;
if (err < 0)
{
if (xrun_recovery(alsa->pcm_handle, err) < 0)
{
st_fail_errno(ft, ST_EPERM, "ALSA write error");
return ST_EOF;
}
}
else
{
read_buf(buf+(len*sizeof(st_sample_t)), alsa->buf, err, ft->swap);
len += err * ft->info.channels;
}
}
return len;
}
int st_alsastopread(ft)
ft_t ft;
{
alsa_priv_t alsa = (alsa_priv_t)ft->priv;
snd_pcm_close(alsa->pcm_handle);
free(alsa->buf);
return ST_SUCCESS;
}
int st_alsastartwrite(ft_t ft)
{
return st_alsasetup(ft, SND_PCM_STREAM_PLAYBACK);
}
st_ssize_t st_alsawrite(ft_t ft, st_sample_t *buf, st_ssize_t nsamp)
{
st_ssize_t len;
int err;
alsa_priv_t alsa = (alsa_priv_t)ft->priv;
void (*write_buf)(char *, st_sample_t *, st_ssize_t, char) = 0;
switch(ft->info.size) {
case ST_SIZE_BYTE:
switch(ft->info.encoding)
{
case ST_ENCODING_SIGN2:
write_buf = st_sb_write_buf;
break;
case ST_ENCODING_UNSIGNED:
write_buf = st_ub_write_buf;
break;
default:
st_fail_errno(ft,ST_EFMT,"Do not support this encoding for this data size");
return ST_EOF;
}
break;
case ST_SIZE_WORD:
switch(ft->info.encoding)
{
case ST_ENCODING_SIGN2:
write_buf = st_sw_write_buf;
break;
case ST_ENCODING_UNSIGNED:
write_buf = st_uw_write_buf;
break;
default:
st_fail_errno(ft,ST_EFMT,"Do not support this encoding for this data size");
return ST_EOF;
}
break;
default:
st_fail_errno(ft,ST_EFMT,"Do not support this data size for this handler");
return ST_EOF;
}
/* Prevent overflow */
if (nsamp > alsa->buf_size/ft->info.size)
nsamp = (alsa->buf_size/ft->info.size);
len = 0;
write_buf(alsa->buf, buf, nsamp, ft->swap);
while (len < nsamp)
{
err = snd_pcm_writei(alsa->pcm_handle,
alsa->buf+(len*ft->info.size),
(nsamp-len)/ft->info.channels);
if (err == -EAGAIN)
continue;
if (err < 0)
{
if (xrun_recovery(alsa->pcm_handle, err) < 0)
{
st_fail_errno(ft, ST_EPERM, "ALSA write error\n");
return ST_EOF;
}
}
else
len += err * ft->info.channels;
}
return len;
}
int st_alsastopwrite(ft)
ft_t ft;
{
alsa_priv_t alsa = (alsa_priv_t)ft->priv;
snd_pcm_drain(alsa->pcm_handle);
snd_pcm_close(alsa->pcm_handle);
free(alsa->buf);
return ST_SUCCESS;
}
#define EMSGFMT "ALSA driver does not support %s %s output"
static int get_format(ft_t ft, snd_pcm_format_mask_t *fmask, int *fmt)
{
if (ft->info.size == -1)
ft->info.size = ST_SIZE_WORD;
if (ft->info.encoding == -1)
{
if (ft->info.size == ST_SIZE_WORD)
ft->info.encoding = ST_ENCODING_SIGN2;
else
ft->info.encoding = ST_ENCODING_UNSIGNED;
}
if (ft->info.size != ST_SIZE_WORD &&
ft->info.size != ST_SIZE_BYTE)
{
st_report("ALSA driver only supports byte and word samples. Changing to word.");
ft->info.size = ST_SIZE_WORD;
}
if (ft->info.encoding != ST_ENCODING_SIGN2 &&
ft->info.encoding != ST_ENCODING_UNSIGNED)
{
if (ft->info.size == ST_SIZE_WORD)
{
st_report("ALSA driver only supports signed and unsigned samples. Changing to signed.");
ft->info.encoding = ST_ENCODING_SIGN2;
}
else
{
st_report("ALSA driver only supports signed and unsigned samples. Changing to unsigned.");
ft->info.encoding = ST_ENCODING_UNSIGNED;
}
}
/* Some hardware only wants to work with 8-bit or 16-bit data */
if (ft->info.size == ST_SIZE_BYTE)
{
if (!(snd_pcm_format_mask_test(fmask, SND_PCM_FORMAT_U8)) &&
!(snd_pcm_format_mask_test(fmask, SND_PCM_FORMAT_S8)))
{
st_report("ALSA driver doesn't supported byte samples. Changing to words.");
ft->info.size = ST_SIZE_WORD;
}
}
else if (ft->info.size == ST_SIZE_WORD)
{
if (!(snd_pcm_format_mask_test(fmask, SND_PCM_FORMAT_U16)) &&
!(snd_pcm_format_mask_test(fmask, SND_PCM_FORMAT_S16)))
{
st_report("ALSA driver doesn't supported word samples. Changing to bytes.");
ft->info.size = ST_SIZE_BYTE;
}
}
else
{
if ((snd_pcm_format_mask_test(fmask, SND_PCM_FORMAT_U16)) ||
(snd_pcm_format_mask_test(fmask, SND_PCM_FORMAT_S16)))
{
st_report("ALSA driver doesn't supported %s samples. Changing to words.", st_sizes_str[(unsigned char)ft->info.size]);
ft->info.size = ST_SIZE_WORD;
}
else
{
st_report("ALSA driver doesn't supported %s samples. Changing to bytes.", st_sizes_str[(unsigned char)ft->info.size]);
ft->info.size = ST_SIZE_BYTE;
}
}
if (ft->info.size == ST_SIZE_BYTE) {
switch (ft->info.encoding)
{
case ST_ENCODING_SIGN2:
if (!(snd_pcm_format_mask_test(fmask, SND_PCM_FORMAT_S8)))
{
st_report("ALSA driver doesn't supported signed byte samples. Changing to unsigned bytes.");
ft->info.encoding = ST_ENCODING_UNSIGNED;
}
break;
case ST_ENCODING_UNSIGNED:
if (!(snd_pcm_format_mask_test(fmask, SND_PCM_FORMAT_U8)))
{
st_report("ALSA driver doesn't supported unsigned byte samples. Changing to signed bytes.");
ft->info.encoding = ST_ENCODING_SIGN2;
}
break;
}
switch (ft->info.encoding)
{
case ST_ENCODING_SIGN2:
if (!(snd_pcm_format_mask_test(fmask, SND_PCM_FORMAT_S8)))
{
st_fail_errno(ft,ST_EFMT,"ALSA driver does not support signed byte samples");
return ST_EOF;
}
*fmt = SND_PCM_FORMAT_S8;
break;
case ST_ENCODING_UNSIGNED:
if (!(snd_pcm_format_mask_test(fmask, SND_PCM_FORMAT_U8)))
{
st_fail_errno(ft,ST_EFMT,"ALSA driver does not support unsigned byte samples");
return ST_EOF;
}
*fmt = SND_PCM_FORMAT_U8;
break;
}
}
else if (ft->info.size == ST_SIZE_WORD) {
switch (ft->info.encoding)
{
case ST_ENCODING_SIGN2:
if (!(snd_pcm_format_mask_test(fmask, SND_PCM_FORMAT_S16)))
{
st_report("ALSA driver does not support signed word samples. Changing to unsigned words.");
ft->info.encoding = ST_ENCODING_UNSIGNED;
}
break;
case ST_ENCODING_UNSIGNED:
if (!(snd_pcm_format_mask_test(fmask, SND_PCM_FORMAT_U16)))
{
st_report("ALSA driver does not support unsigned word samples. Changing to signed words.");
ft->info.encoding = ST_ENCODING_SIGN2;
}
break;
}
switch (ft->info.encoding)
{
case ST_ENCODING_SIGN2:
if (!(snd_pcm_format_mask_test(fmask, SND_PCM_FORMAT_S16)))
{
st_fail_errno(ft,ST_EFMT,"ALSA driver does not support signed word samples");
return ST_EOF;
}
*fmt = SND_PCM_FORMAT_S16_LE;
break;
case ST_ENCODING_UNSIGNED:
if (!(snd_pcm_format_mask_test(fmask, SND_PCM_FORMAT_U16)))
{
st_fail_errno(ft,ST_EFMT,"ALSA driver does not support unsigned word samples");
return ST_EOF;
}
*fmt = SND_PCM_FORMAT_U16_LE;
break;
}
}
else {
st_fail_errno(ft,ST_EFMT,EMSGFMT,st_encodings_str[(unsigned char)ft->info.encoding], st_sizes_str[(unsigned char)ft->info.size]);
return ST_EOF;
}
return 0;
}
#endif /* HAVE_ALSA */