Forward the number of skipped frames by the OS in audio playout.

media/audio/mac/audio_auhal_mac.cc

 // Copyright 2013 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "media/audio/mac/audio_auhal_mac.h"
 
 #include <CoreServices/CoreServices.h>
 
 #include "base/basictypes.h"
 #include "base/bind.h"
@@ skipping 35 matching lines @@
       output_channels_(params_.channels()),
       number_of_frames_(params_.frames_per_buffer()),
       number_of_frames_requested_(0),
       source_(NULL),
       device_(device),
       audio_unit_(0),
       volume_(1),
       hardware_latency_frames_(0),
       stopped_(true),
       current_hardware_pending_bytes_(0),
+      current_lost_frames_(0),
       last_sample_time_(0.0),
       last_number_of_frames_(0),
       total_lost_frames_(0),
       largest_glitch_frames_(0),
       glitches_detected_(0) {
   // We must have a manager.
   DCHECK(manager_);
 
   DVLOG(1) << "AUHALStream::AUHALStream()";
   DVLOG(1) << "Device: " << device;
@@ skipping 133 matching lines @@
 OSStatus AUHALStream::Render(
     AudioUnitRenderActionFlags* flags,
     const AudioTimeStamp* output_time_stamp,
     UInt32 bus_number,
     UInt32 number_of_frames,
     AudioBufferList* data) {
   TRACE_EVENT0("audio", "AUHALStream::Render");
 
   UpdatePlayoutTimestamp(output_time_stamp);
 
+  // Inform the source about any skipped (lost) frames. If we use a fifo this
+  // will be out of sync with the fifo pulls (different buffer sizes), so we do
+  // it here and not in ProvideInput().
+  if (lost_frames > 0) {
+    base::AutoLock auto_lock(source_lock_);
+    if (source_)
+      source_->OnSkippedData(lost_frames);
+  }
+
   // If the stream parameters change for any reason, we need to insert a FIFO
   // since the OnMoreData() pipeline can't handle frame size changes.
   if (number_of_frames != number_of_frames_) {
     // Create a FIFO on the fly to handle any discrepancies in callback rates.
     if (!audio_fifo_) {
       number_of_frames_requested_ = number_of_frames;
       DVLOG(1) << "Audio frame size changed from " << number_of_frames_
                << " to " << number_of_frames
                << "; adding FIFO to compensate.";
       audio_fifo_.reset(new AudioPullFifo(
@@ skipping 22 matching lines @@
 }
 
 void AUHALStream::ProvideInput(int frame_delay, AudioBus* dest) {
   base::AutoLock auto_lock(source_lock_);
   if (!source_) {
     dest->Zero();
     return;
   }
 
   // Supply the input data and render the output data.
-  source_->OnMoreData(
-      dest,
-      current_hardware_pending_bytes_ +
-      frame_delay * params_.GetBytesPerFrame());
+  source_->OnMoreData(dest, current_hardware_pending_bytes_ +
+                                frame_delay * params_.GetBytesPerFrame(),
+                      current_lost_frames_);
   dest->Scale(volume_);
+  current_lost_frames_ = 0;
 }
 
 // AUHAL callback.
 OSStatus AUHALStream::InputProc(
     void* user_data,
     AudioUnitRenderActionFlags* flags,
     const AudioTimeStamp* output_time_stamp,
     UInt32 bus_number,
     UInt32 number_of_frames,
     AudioBufferList* io_data) {
@@ skipping 85 matching lines @@
     return;
 
   if (last_sample_time_) {
     DCHECK_NE(0U, last_number_of_frames_);
     UInt32 diff =
         static_cast<UInt32>(timestamp->mSampleTime - last_sample_time_);
     if (diff != last_number_of_frames_) {
       DCHECK_GT(diff, last_number_of_frames_);
       // We're being asked to render samples post what we expected. Update the
       // glitch count etc and keep a record of the largest glitch.
-      auto lost_frames = diff - last_number_of_frames_;
+      UInt32 lost_frames = diff - last_number_of_frames_;
       total_lost_frames_ += lost_frames;
+      current_lost_frames_ += lost_frames;
       if (lost_frames > largest_glitch_frames_)
         largest_glitch_frames_ = lost_frames;
       ++glitches_detected_;
     }
   }
 
   // Store the last sample time for use next time we get called back.
   last_sample_time_ = timestamp->mSampleTime;
 }
 
@@ skipping 165 matching lines @@
   OSStatus result = AudioUnitUninitialize(audio_unit_);
   OSSTATUS_DLOG_IF(ERROR, result != noErr, result)
       << "AudioUnitUninitialize() failed.";
   result = AudioComponentInstanceDispose(audio_unit_);
   OSSTATUS_DLOG_IF(ERROR, result != noErr, result)
       << "AudioComponentInstanceDispose() failed.";
   audio_unit_ = 0;
 }
 
 }  // namespace media