static av_cold int audio_read_header(AVFormatContext *s1,
AVFormatParameters *ap)
{
AlsaData *s = s1->priv_data;
AVStream *st;
int ret;
enum CodecID codec_id;
snd_pcm_sw_params_t *sw_params;
st = av_new_stream(s1, 0);
if (!st) {
av_log(s1, AV_LOG_ERROR, "Cannot add stream\n");
return AVERROR(ENOMEM);
}
codec_id = s1->audio_codec_id;
ret = ff_alsa_open(s1, SND_PCM_STREAM_CAPTURE, &s->sample_rate, s->channels,
&codec_id);
if (ret < 0) {
return AVERROR(EIO);
}
if (snd_pcm_type(s->h) != SND_PCM_TYPE_HW)
av_log(s1, AV_LOG_WARNING,
"capture with some ALSA plugins, especially dsnoop, "
"may hang.\n");
ret = snd_pcm_sw_params_malloc(&sw_params);
if (ret < 0) {
av_log(s1, AV_LOG_ERROR, "cannot allocate software parameters structure (%s)\n",
snd_strerror(ret));
goto fail;
}
snd_pcm_sw_params_current(s->h, sw_params);
snd_pcm_sw_params_set_tstamp_mode(s->h, sw_params, SND_PCM_TSTAMP_ENABLE);
ret = snd_pcm_sw_params(s->h, sw_params);
snd_pcm_sw_params_free(sw_params);
if (ret < 0) {
av_log(s1, AV_LOG_ERROR, "cannot install ALSA software parameters (%s)\n",
snd_strerror(ret));
goto fail;
}
/* take real parameters */
st->codec->codec_type = AVMEDIA_TYPE_AUDIO;
st->codec->codec_id = codec_id;
st->codec->sample_rate = s->sample_rate;
st->codec->channels = s->channels;
av_set_pts_info(st, 64, 1, 1000000); /* 64 bits pts in us */
return 0;
fail:
snd_pcm_close(s->h);
return AVERROR(EIO);
}
static int setparams_set(snd_pcm_t *handle,
snd_pcm_hw_params_t *params,
snd_pcm_sw_params_t *swparams,
snd_pcm_uframes_t start_treshold,
const char *id)
{
int err;
err = snd_pcm_hw_params(handle, params);
if (err < 0) {
fprintf(error_fp, "alsa: Unable to set hw params for %s: %s\n",
id, snd_strerror(err));
return err;
}
err = snd_pcm_sw_params_current(handle, swparams);
if (err < 0) {
fprintf(error_fp, "alsa: Unable to determine current swparams for %s: %s\n",
id, snd_strerror(err));
return err;
}
err = snd_pcm_sw_params_set_start_threshold(handle, swparams,
start_treshold);
if (err < 0) {
fprintf(error_fp, "alsa: Unable to set start threshold mode for %s: %s\n",
id, snd_strerror(err));
return err;
}
err = snd_pcm_sw_params_set_avail_min(handle, swparams, 4);
if (err < 0) {
fprintf(error_fp, "alsa: Unable to set avail min for %s: %s\n",
id, snd_strerror(err));
return err;
}
err = snd_pcm_sw_params_set_tstamp_mode(handle, swparams, SND_PCM_TSTAMP_ENABLE);
if (err < 0) {
fprintf(error_fp, "alsa: Unable to enable timestamps for %s: %s\n",
id, snd_strerror(err));
}
err = snd_pcm_sw_params(handle, swparams);
if (err < 0) {
fprintf(error_fp, "alsa: Unable to set sw params for %s: %s\n",
id, snd_strerror(err));
return err;
}
return 0;
}
int main(int argc, char *argv[]) {
const char *dev;
int r, cap, count = 0;
snd_pcm_hw_params_t *hwparams;
snd_pcm_sw_params_t *swparams;
snd_pcm_status_t *status;
snd_pcm_t *pcm;
unsigned rate = 44100;
unsigned periods = 2;
snd_pcm_uframes_t boundary, buffer_size = 44100/10; /* 100s */
int dir = 1;
struct timespec start, last_timestamp = { 0, 0 };
uint64_t start_us, last_us = 0;
snd_pcm_sframes_t last_avail = 0, last_delay = 0;
struct pollfd *pollfds;
int n_pollfd;
int64_t sample_count = 0;
struct sched_param sp;
r = -1;
#ifdef _POSIX_PRIORITY_SCHEDULING
sp.sched_priority = 5;
r = pthread_setschedparam(pthread_self(), SCHED_RR, &sp);
#endif
if (r)
printf("Could not get RT prio. :(\n");
snd_pcm_hw_params_alloca(&hwparams);
snd_pcm_sw_params_alloca(&swparams);
snd_pcm_status_alloca(&status);
r = clock_gettime(CLOCK_MONOTONIC, &start);
assert(r == 0);
start_us = timespec_us(&start);
dev = argc > 1 ? argv[1] : "front:AudioPCI";
cap = argc > 2 ? atoi(argv[2]) : 0;
if (cap == 0)
r = snd_pcm_open(&pcm, dev, SND_PCM_STREAM_PLAYBACK, 0);
else
r = snd_pcm_open(&pcm, dev, SND_PCM_STREAM_CAPTURE, 0);
assert(r == 0);
r = snd_pcm_hw_params_any(pcm, hwparams);
assert(r == 0);
r = snd_pcm_hw_params_set_rate_resample(pcm, hwparams, 0);
assert(r == 0);
r = snd_pcm_hw_params_set_access(pcm, hwparams, SND_PCM_ACCESS_RW_INTERLEAVED);
assert(r == 0);
r = snd_pcm_hw_params_set_format(pcm, hwparams, SND_PCM_FORMAT_S16_LE);
assert(r == 0);
r = snd_pcm_hw_params_set_rate_near(pcm, hwparams, &rate, NULL);
assert(r == 0);
r = snd_pcm_hw_params_set_channels(pcm, hwparams, 2);
assert(r == 0);
r = snd_pcm_hw_params_set_periods_integer(pcm, hwparams);
assert(r == 0);
r = snd_pcm_hw_params_set_periods_near(pcm, hwparams, &periods, &dir);
assert(r == 0);
r = snd_pcm_hw_params_set_buffer_size_near(pcm, hwparams, &buffer_size);
assert(r == 0);
r = snd_pcm_hw_params(pcm, hwparams);
assert(r == 0);
r = snd_pcm_hw_params_current(pcm, hwparams);
assert(r == 0);
r = snd_pcm_sw_params_current(pcm, swparams);
assert(r == 0);
if (cap == 0)
r = snd_pcm_sw_params_set_avail_min(pcm, swparams, 1);
else
r = snd_pcm_sw_params_set_avail_min(pcm, swparams, 0);
assert(r == 0);
r = snd_pcm_sw_params_set_period_event(pcm, swparams, 0);
assert(r == 0);
r = snd_pcm_hw_params_get_buffer_size(hwparams, &buffer_size);
assert(r == 0);
r = snd_pcm_sw_params_set_start_threshold(pcm, swparams, buffer_size);
assert(r == 0);
r = snd_pcm_sw_params_get_boundary(swparams, &boundary);
assert(r == 0);
r = snd_pcm_sw_params_set_stop_threshold(pcm, swparams, boundary);
assert(r == 0);
r = snd_pcm_sw_params_set_tstamp_mode(pcm, swparams, SND_PCM_TSTAMP_ENABLE);
assert(r == 0);
r = snd_pcm_sw_params(pcm, swparams);
assert(r == 0);
r = snd_pcm_prepare(pcm);
assert(r == 0);
r = snd_pcm_sw_params_current(pcm, swparams);
assert(r == 0);
/* assert(snd_pcm_hw_params_is_monotonic(hwparams) > 0); */
n_pollfd = snd_pcm_poll_descriptors_count(pcm);
assert(n_pollfd > 0);
pollfds = malloc(sizeof(struct pollfd) * n_pollfd);
assert(pollfds);
r = snd_pcm_poll_descriptors(pcm, pollfds, n_pollfd);
assert(r == n_pollfd);
printf("Starting. Buffer size is %u frames\n", (unsigned int) buffer_size);
if (cap) {
r = snd_pcm_start(pcm);
assert(r == 0);
}
for (;;) {
snd_pcm_sframes_t avail, delay;
struct timespec now, timestamp;
unsigned short revents;
int handled = 0;
uint64_t now_us, timestamp_us;
snd_pcm_state_t state;
unsigned long long pos;
r = poll(pollfds, n_pollfd, 0);
assert(r >= 0);
r = snd_pcm_poll_descriptors_revents(pcm, pollfds, n_pollfd, &revents);
assert(r == 0);
if (cap == 0)
assert((revents & ~POLLOUT) == 0);
else
assert((revents & ~POLLIN) == 0);
avail = snd_pcm_avail(pcm);
assert(avail >= 0);
r = snd_pcm_status(pcm, status);
assert(r == 0);
/* This assertion fails from time to time. ALSA seems to be broken */
/* assert(avail == (snd_pcm_sframes_t) snd_pcm_status_get_avail(status)); */
/* printf("%lu %lu\n", (unsigned long) avail, (unsigned long) snd_pcm_status_get_avail(status)); */
snd_pcm_status_get_htstamp(status, ×tamp);
delay = snd_pcm_status_get_delay(status);
state = snd_pcm_status_get_state(status);
r = clock_gettime(CLOCK_MONOTONIC, &now);
assert(r == 0);
assert(!revents || avail > 0);
if ((!cap && avail) || (cap && (unsigned)avail >= buffer_size)) {
snd_pcm_sframes_t sframes;
static const uint16_t psamples[2] = { 0, 0 };
uint16_t csamples[2];
if (cap == 0)
sframes = snd_pcm_writei(pcm, psamples, 1);
else
sframes = snd_pcm_readi(pcm, csamples, 1);
assert(sframes == 1);
handled = 1;
sample_count++;
}
if (!handled &&
memcmp(×tamp, &last_timestamp, sizeof(timestamp)) == 0 &&
avail == last_avail &&
delay == last_delay) {
/* This is boring */
continue;
}
now_us = timespec_us(&now);
timestamp_us = timespec_us(×tamp);
if (cap == 0)
pos = (unsigned long long) ((sample_count - handled - delay) * 1000000LU / 44100);
else
pos = (unsigned long long) ((sample_count - handled + delay) * 1000000LU / 44100);
if (count++ % 50 == 0)
printf("Elapsed\tCPU\tALSA\tPos\tSamples\tavail\tdelay\trevents\thandled\tstate\n");
printf("%llu\t%llu\t%llu\t%llu\t%llu\t%li\t%li\t%i\t%i\t%i\n",
(unsigned long long) (now_us - last_us),
(unsigned long long) (now_us - start_us),
(unsigned long long) (timestamp_us ? timestamp_us - start_us : 0),
pos,
(unsigned long long) sample_count,
(signed long) avail,
(signed long) delay,
revents,
handled,
state);
if (cap == 0)
/** When this assert is hit, most likely something bad
* happened, i.e. the avail jumped suddenly. */
assert((unsigned) avail <= buffer_size);
last_avail = avail;
last_delay = delay;
last_timestamp = timestamp;
last_us = now_us;
}
return 0;
}
static int
set_swparams (GstAlsaSrc * alsa)
{
int err;
snd_pcm_sw_params_t *params;
snd_pcm_sw_params_malloc (¶ms);
/* get the current swparams */
CHECK (snd_pcm_sw_params_current (alsa->handle, params), no_config);
/* allow the transfer when at least period_size samples can be processed */
CHECK (snd_pcm_sw_params_set_avail_min (alsa->handle, params,
alsa->period_size), set_avail);
/* start the transfer on first read */
CHECK (snd_pcm_sw_params_set_start_threshold (alsa->handle, params,
0), start_threshold);
/* use monotonic timestamping */
CHECK (snd_pcm_sw_params_set_tstamp_mode (alsa->handle, params,
SND_PCM_TSTAMP_MMAP), tstamp_mode);
#if GST_CHECK_ALSA_VERSION(1,0,16)
/* snd_pcm_sw_params_set_xfer_align() is deprecated, alignment is always 1 */
#else
/* align all transfers to 1 sample */
CHECK (snd_pcm_sw_params_set_xfer_align (alsa->handle, params, 1), set_align);
#endif
/* write the parameters to the recording device */
CHECK (snd_pcm_sw_params (alsa->handle, params), set_sw_params);
snd_pcm_sw_params_free (params);
return 0;
/* ERRORS */
no_config:
{
GST_ELEMENT_ERROR (alsa, RESOURCE, SETTINGS, (NULL),
("Unable to determine current swparams for playback: %s",
snd_strerror (err)));
snd_pcm_sw_params_free (params);
return err;
}
start_threshold:
{
GST_ELEMENT_ERROR (alsa, RESOURCE, SETTINGS, (NULL),
("Unable to set start threshold mode for playback: %s",
snd_strerror (err)));
snd_pcm_sw_params_free (params);
return err;
}
set_avail:
{
GST_ELEMENT_ERROR (alsa, RESOURCE, SETTINGS, (NULL),
("Unable to set avail min for playback: %s", snd_strerror (err)));
snd_pcm_sw_params_free (params);
return err;
}
tstamp_mode:
{
GST_ELEMENT_ERROR (alsa, RESOURCE, SETTINGS, (NULL),
("Unable to set tstamp mode for playback: %s", snd_strerror (err)));
snd_pcm_sw_params_free (params);
return err;
}
#if !GST_CHECK_ALSA_VERSION(1,0,16)
set_align:
{
GST_ELEMENT_ERROR (alsa, RESOURCE, SETTINGS, (NULL),
("Unable to set transfer align for playback: %s", snd_strerror (err)));
snd_pcm_sw_params_free (params);
return err;
}
#endif
set_sw_params:
{
GST_ELEMENT_ERROR (alsa, RESOURCE, SETTINGS, (NULL),
("Unable to set sw params for playback: %s", snd_strerror (err)));
snd_pcm_sw_params_free (params);
return err;
}
}
