Merge pull request #101 from HEnquist/noblock

Noblock

CHANGELOG.md

@@ -18,6 +18,7 @@ New features:
 - Add `debug` feature for extra logging.
 - Improve validation of filters.
 - Setting to enable retry on reads from Alsa capture devices.
+- Avoid blocking reads on Alsa capture devices (helps avoiding driver bugs for some devices).
 
 Bugfixes:
 - Don't block playback for CoreAudio/Wasapi if there is no data in time.

Cargo.toml

@@ -1,6 +1,6 @@
 [package]
 name = "camilladsp"
-version = "0.5.0"
+version = "0.5.0-beta5"
 authors = ["Henrik Enquist <[email protected]>"]
 description = "A flexible tool for processing audio"
 

src/alsadevice.rs

@@ -131,17 +131,58 @@ fn play_buffer(
     Ok(())
 }
 
-/// Play a buffer.
+/// Capture a buffer.
 fn capture_buffer(
     buffer: &mut [u8],
     pcmdevice: &alsa::PCM,
     io: &alsa::pcm::IO<u8>,
     retry: bool,
+    samplerate: usize,
+    frames_to_read: usize,
 ) -> Res<CaptureResult> {
     let capture_state = pcmdevice.state();
     if capture_state == State::XRun {
-        warn!("prepare capture");
+        warn!("Prepare capture device");
         pcmdevice.prepare()?;
+    } else if capture_state != State::Running {
+        debug!("Starting capture");
+        pcmdevice.start()?;
+    }
+    let available = pcmdevice.avail();
+    match available {
+        Ok(frames) => {
+            if (frames as usize) < frames_to_read {
+                trace!(
+                    "Not enough frames available: {}, need: {}, waiting...",
+                    frames,
+                    frames_to_read
+                );
+                // Let's wait for more frames, with 10% plus 1 ms of margin
+                thread::sleep(Duration::from_millis(
+                    (1 + (1100 * (frames_to_read - frames as usize)) / samplerate) as u64,
+                ));
+                if (pcmdevice.avail().unwrap_or(0) as usize) < frames_to_read {
+                    // Still not enough,
+                    warn!("Capture timed out, will try again");
+                    return Ok(CaptureResult::RecoverableError);
+                }
+            }
+        }
+        Err(err) => {
+            if retry {
+                warn!("Capture failed while querying for available frames, error: {}, will try again.", err);
+                thread::sleep(Duration::from_millis(
+                    (1000 * frames_to_read as u64) / samplerate as u64,
+                ));
+                return Ok(CaptureResult::RecoverableError);
+            } else {
+                warn!(
+                    "Capture failed while querying for available frames, error: {}",
+                    err
+                );
+                return Err(Box::new(err));
+            }
+        }
     }
     let _frames = match io.readi(buffer) {
         Ok(frames) => frames,
@@ -151,7 +192,7 @@ fn capture_buffer(
                     warn!("Capture failed with error: {}, will try again.", err);
                     return Ok(CaptureResult::RecoverableError);
                 } else {
-                    warn!("Capture failed, error: {}", err);
+                    warn!("Capture failed with error: {}", err);
                     return Err(Box::new(err));
                 }
             }
@@ -397,6 +438,8 @@ fn capture_loop_bytes(
             pcmdevice,
             &io,
             params.retry_on_error,
+            params.capture_samplerate,
+            capture_bytes / (params.channels * params.store_bytes_per_sample),
         );
         match capture_res {
             Ok(CaptureResult::Normal) => {