def _set_start_time(self, source, timestamp):
delay = asound.snd_pcm_sframes_t()
check(asound.snd_pcm_delay(self._device.pcm, ctypes.byref(delay)))
delay = (delay.value /
source.audio_format.bytes_per_sample /
float(source.audio_format.bytes_per_second))
self._start_time = self._get_asound_time() - timestamp - delay
def write(self, audio_data):
samples = audio_data.length // self.audio_format.bytes_per_sample
samples_out = asound.snd_pcm_writei(self.pcm, audio_data.data, samples)
if samples_out < 0:
if samples_out == -11: # EAGAIN
return
elif samples_out == -32: # EPIPE (xrun)
check(asound.snd_pcm_prepare(self.pcm))
return
else:
raise ALSAException(asound.snd_strerror(samples_out))
delay = asound.snd_pcm_sframes_t()
check(asound.snd_pcm_delay(self.pcm, delay))
alsatime = self._get_asound_time() + \
delay.value / float(self.audio_format.sample_rate)
self._timestamps.append((alsatime, audio_data.timestamp))
audio_data.consume(samples_out * self.audio_format.bytes_per_sample,
self.audio_format)
def write(self, audio_data):
samples = audio_data.length // self.audio_format.bytes_per_sample
samples_out = asound.snd_pcm_writei(self.pcm, audio_data.data,
samples)
if samples_out < 0:
if samples_out == -11: # EAGAIN
return
elif samples_out == -32: # EPIPE (xrun)
check(asound.snd_pcm_prepare(self.pcm))
return
else:
raise ALSAException(asound.snd_strerror(samples_out))
delay = asound.snd_pcm_sframes_t()
check(asound.snd_pcm_delay(self.pcm, delay))
alsatime = self._get_asound_time() + \
delay.value / float(self.audio_format.sample_rate)
self._timestamps.append((alsatime, audio_data.timestamp))
audio_data.consume(samples_out * self.audio_format.bytes_per_sample,
self.audio_format)
