diff --git a/playback/src/audio_backend/alsa.rs b/playback/src/audio_backend/alsa.rs index a9a593a3..7b5987a3 100644 --- a/playback/src/audio_backend/alsa.rs +++ b/playback/src/audio_backend/alsa.rs @@ -152,10 +152,15 @@ fn open_device(dev_name: &str, format: AudioFormat) -> Result<(PCM, usize), Alsa pcm.sw_params(&swp).map_err(AlsaError::Pcm)?; + trace!("Frames per Buffer: {:?}", frames_per_buffer); + trace!("Frames per Period: {:?}", frames_per_period); + // Let ALSA do the math for us. pcm.frames_to_bytes(frames_per_period) as usize }; + trace!("Period Buffer size in bytes: {:?}", bytes_per_period); + Ok((pcm, bytes_per_period)) } @@ -193,7 +198,22 @@ impl Sink for AlsaSink { match open_device(&self.device, self.format) { Ok((pcm, bytes_per_period)) => { self.pcm = Some(pcm); - self.period_buffer = Vec::with_capacity(bytes_per_period); + // If the capacity is greater than we want shrink it + // to it's current len (which should be zero) before + // setting the capacity with reserve_exact. + if self.period_buffer.capacity() > bytes_per_period { + self.period_buffer.shrink_to_fit(); + } + // This does nothing if the capacity is already sufficient. + // Len should always be zero, but for the sake of being thorough... + self.period_buffer + .reserve_exact(bytes_per_period - self.period_buffer.len()); + + // Should always match the "Period Buffer size in bytes: " trace! message. + trace!( + "Period Buffer capacity: {:?}", + self.period_buffer.capacity() + ); } Err(e) => { return Err(io::Error::new(io::ErrorKind::Other, e)); @@ -205,20 +225,22 @@ impl Sink for AlsaSink { } fn stop(&mut self) -> io::Result<()> { - { - // Write any leftover data in the period buffer - // before draining the actual buffer - self.write_bytes(&[])?; - let pcm = self.pcm.as_mut().ok_or_else(|| { - io::Error::new(io::ErrorKind::Other, "Error stopping AlsaSink, PCM is None") - })?; - pcm.drain().map_err(|e| { - io::Error::new( - io::ErrorKind::Other, - format!("Error stopping AlsaSink {}", e), - ) - })? - } + // Zero fill the remainder of the period buffer and + // write any leftover data before draining the actual PCM buffer. + self.period_buffer.resize(self.period_buffer.capacity(), 0); + self.write_buf()?; + + let pcm = self.pcm.as_mut().ok_or_else(|| { + io::Error::new(io::ErrorKind::Other, "Error stopping AlsaSink, PCM is None") + })?; + + pcm.drain().map_err(|e| { + io::Error::new( + io::ErrorKind::Other, + format!("Error stopping AlsaSink {}", e), + ) + })?; + self.pcm = None; Ok(()) } @@ -228,22 +250,24 @@ impl Sink for AlsaSink { impl SinkAsBytes for AlsaSink { fn write_bytes(&mut self, data: &[u8]) -> io::Result<()> { - let mut processed_data = 0; - while processed_data < data.len() { - let data_to_buffer = min( - self.period_buffer.capacity() - self.period_buffer.len(), - data.len() - processed_data, - ); + let mut start_index = 0; + let data_len = data.len(); + let capacity = self.period_buffer.capacity(); + loop { + let data_left = data_len - start_index; + let space_left = capacity - self.period_buffer.len(); + let data_to_buffer = min(data_left, space_left); + let end_index = start_index + data_to_buffer; self.period_buffer - .extend_from_slice(&data[processed_data..processed_data + data_to_buffer]); - processed_data += data_to_buffer; - if self.period_buffer.len() == self.period_buffer.capacity() { + .extend_from_slice(&data[start_index..end_index]); + if self.period_buffer.len() == capacity { self.write_buf()?; - self.period_buffer.clear(); } + if end_index == data_len { + break Ok(()); + } + start_index = end_index; } - - Ok(()) } } @@ -276,6 +300,7 @@ impl AlsaSink { })? } + self.period_buffer.clear(); Ok(()) } }