/* Return the best matching sample format for the requested format and
* available format mask. */
static long sfmt_best_matching (const long formats_with_endian,
const long req_with_endian)
{
long formats = formats_with_endian & SFMT_MASK_FORMAT;
long req = req_with_endian & SFMT_MASK_FORMAT;
long best = 0;
#ifdef DEBUG
char fmt_name1[SFMT_STR_MAX];
char fmt_name2[SFMT_STR_MAX];
#endif
if (formats & req)
best = req;
else if (req == SFMT_S8 || req == SFMT_U8) {
if (formats & SFMT_S8)
best = SFMT_S8;
else if (formats & SFMT_U8)
best = SFMT_U8;
else if (formats & SFMT_S16)
best = SFMT_S16;
else if (formats & SFMT_U16)
best = SFMT_U16;
else if (formats & SFMT_S32)
best = SFMT_S32;
else if (formats & SFMT_U32)
best = SFMT_U32;
else if (formats & SFMT_FLOAT)
best = SFMT_FLOAT;
}
else if (req == SFMT_S16 || req == SFMT_U16) {
if (formats & SFMT_S16)
best = SFMT_S16;
else if (formats & SFMT_U16)
best = SFMT_U16;
else if (formats & SFMT_S32)
best = SFMT_S32;
else if (formats & SFMT_U32)
best = SFMT_U32;
else if (formats & SFMT_FLOAT)
best = SFMT_FLOAT;
else if (formats & SFMT_S8)
best = SFMT_S8;
else if (formats & SFMT_U8)
best = SFMT_U8;
}
else if (req == SFMT_S32 || req == SFMT_U32 || req == SFMT_FLOAT) {
if (formats & SFMT_S32)
best = SFMT_S32;
else if (formats & SFMT_U32)
best = SFMT_U32;
else if (formats & SFMT_S16)
best = SFMT_S16;
else if (formats & SFMT_U16)
best = SFMT_U16;
else if (formats & SFMT_FLOAT)
best = SFMT_FLOAT;
else if (formats & SFMT_S8)
best = SFMT_S8;
else if (formats & SFMT_U8)
best = SFMT_U8;
}
assert (best != 0);
if (!(best & (SFMT_S8 | SFMT_U8))) {
if ((formats_with_endian & SFMT_LE)
&& (formats_with_endian & SFMT_BE))
best |= SFMT_NE;
else
best |= formats_with_endian & SFMT_MASK_ENDIANNESS;
}
#ifdef DEBUG
debug ("Chose %s as the best matching %s",
sfmt_str(best, fmt_name1, sizeof(fmt_name1)),
sfmt_str(req_with_endian, fmt_name2, sizeof(fmt_name2)));
#endif
return best;
}
static int alsa_open (struct sound_params *sound_params)
{
snd_pcm_hw_params_t *hw_params;
int err;
unsigned int period_time;
unsigned int buffer_time;
snd_pcm_uframes_t chunk_frames;
snd_pcm_uframes_t buffer_frames;
char fmt_name[128];
switch (sound_params->fmt & SFMT_MASK_FORMAT) {
case SFMT_S8:
params.format = SND_PCM_FORMAT_S8;
break;
case SFMT_U8:
params.format = SND_PCM_FORMAT_U8;
break;
case SFMT_S16:
params.format = SND_PCM_FORMAT_S16;
break;
case SFMT_U16:
params.format = SND_PCM_FORMAT_U16;
break;
case SFMT_S32:
params.format = SND_PCM_FORMAT_S32;
break;
case SFMT_U32:
params.format = SND_PCM_FORMAT_U32;
break;
default:
error ("Unknown sample format: %s",
sfmt_str(sound_params->fmt, fmt_name,
sizeof(fmt_name)));
params.format = SND_PCM_FORMAT_UNKNOWN;
return 0;
}
if ((err = snd_pcm_open(&handle, options_get_str("AlsaDevice"),
SND_PCM_STREAM_PLAYBACK,
SND_PCM_NONBLOCK)) < 0) {
error ("Can't open audio: %s", snd_strerror(err));
return 0;
}
if ((err = snd_pcm_hw_params_malloc(&hw_params)) < 0) {
error ("Can't allocate alsa hardware parameters structure: %s",
snd_strerror(err));
return 0;
}
if ((err = snd_pcm_hw_params_any (handle, hw_params)) < 0) {
error ("Can't initialize hardware parameters structure: %s",
snd_strerror(err));
snd_pcm_hw_params_free (hw_params);
return 0;
}
if ((err = snd_pcm_hw_params_set_access (handle, hw_params, SND_PCM_ACCESS_RW_INTERLEAVED)) < 0) {
error ("Can't set alsa access type: %s", snd_strerror(err));
snd_pcm_hw_params_free (hw_params);
return 0;
}
if ((err = snd_pcm_hw_params_set_format (handle, hw_params,
params.format)) < 0) {
error ("Can't set sample format: %s", snd_strerror(err));
snd_pcm_hw_params_free (hw_params);
return 0;
}
params.rate = sound_params->rate;
if ((err = snd_pcm_hw_params_set_rate_near (handle, hw_params,
¶ms.rate, 0)) < 0) {
error ("Can't set sample rate: %s", snd_strerror(err));
snd_pcm_hw_params_free (hw_params);
return 0;
}
logit ("Set rate to %d", params.rate);
if ((err = snd_pcm_hw_params_set_channels (handle, hw_params,
sound_params->channels)) < 0) {
error ("Can't set number of channels: %s", snd_strerror(err));
snd_pcm_hw_params_free (hw_params);
return 0;
}
if ((err = snd_pcm_hw_params_get_buffer_time_max(hw_params,
&buffer_time, 0)) < 0) {
error ("Can't get maximum buffer time: %s", snd_strerror(err));
snd_pcm_hw_params_free (hw_params);
return 0;
}
if (buffer_time > BUFFER_MAX_USEC)
buffer_time = BUFFER_MAX_USEC;
period_time = buffer_time / 4;
if ((err = snd_pcm_hw_params_set_period_time_near(handle, hw_params,
&period_time, 0)) < 0) {
error ("Can't set period time: %s", snd_strerror(err));
snd_pcm_hw_params_free (hw_params);
return 0;
}
if ((err = snd_pcm_hw_params_set_buffer_time_near(handle, hw_params,
&buffer_time, 0)) < 0) {
error ("Can't set buffer time: %s", snd_strerror(err));
snd_pcm_hw_params_free (hw_params);
return 0;
}
if ((err = snd_pcm_hw_params (handle, hw_params)) < 0) {
error ("Can't set audio parameters: %s", snd_strerror(err));
snd_pcm_hw_params_free (hw_params);
return 0;
}
snd_pcm_hw_params_get_period_size (hw_params, &chunk_frames, 0);
snd_pcm_hw_params_get_buffer_size (hw_params, &buffer_frames);
bytes_per_frame = sound_params->channels
* sfmt_Bps(sound_params->fmt);
logit ("Buffer time: %ldus", buffer_frames * bytes_per_frame);
if (chunk_frames == buffer_frames) {
error ("Can't use period equal to buffer size (%lu == %lu)",
chunk_frames, buffer_frames);
snd_pcm_hw_params_free (hw_params);
return 0;
}
chunk_size = chunk_frames * bytes_per_frame;
debug ("Chunk size: %d", chunk_size);
snd_pcm_hw_params_free (hw_params);
if ((err = snd_pcm_prepare(handle)) < 0) {
error ("Can't prepare audio interface for use: %s",
snd_strerror(err));
return 0;
}
debug ("ALSA device initialized");
params.channels = sound_params->channels;
alsa_buf_fill = 0;
return 1;
}
