Resolves crash in media::ChannelMixer::Transform

media/audio/win/audio_unified_win.cc

 // Copyright (c) 2012 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/win/audio_unified_win.h"
 
 #include <Functiondiscoverykeys_devpkey.h>
 
 #include "base/debug/trace_event.h"
 #ifndef NDEBUG
@@ skipping 262 matching lines @@
   SetIOFormats(hw_input_params, params_);
 
   // Create the input and output busses.
   input_bus_ = AudioBus::Create(
       hw_input_params.channels(), input_buffer_size_frames_);
   output_bus_ = AudioBus::Create(params_);
 
   // One extra bus is needed for the input channel mixing case.
   if (channel_mixer_) {
     DCHECK_LT(hw_input_params.channels(), input_channels_);
-    channel_bus_ = AudioBus::Create(input_channels_, input_bus_->frames());
+    // The size of the |channel_bus_| must be the same as the size of the
+    // output bus to ensure that the channel manager can deal with both
+    // resampled and non-resampled data as input.
+    channel_bus_ = AudioBus::Create(
+        input_channels_, params_.frames_per_buffer());
   }
 
   // Check if FIFO and resampling is required to match the input rate to the
   // output rate. If so, a special thread loop, optimized for this case, will
   // be used. This mode is also called varispeed mode.
   // Note that we can also use this mode when input and output rates are the
   // same but native buffer sizes differ (can happen if two different audio
   // devices are used). For this case, the resampler uses a target ratio of
   // 1.0 but SetRatio is called to compensate for clock-drift. The FIFO is
   // required to compensate for the difference in buffer sizes.
@@ skipping 611 matching lines @@
     update_output_delay_ = false;
   }
 
   // Select source depending on if varispeed is utilized or not.
   // Also, the source might be the output of a channel mixer if channel mixing
   // is required to match the native input channels to the number of input
   // channels used by the client (given by |input_channels_| in this case).
   AudioBus* input_bus = VarispeedMode() ?
       resampled_bus_.get() : input_bus_.get();
   if (channel_mixer_) {
+    DCHECK_EQ(input_bus->frames(), channel_bus_->frames());
     // Most common case is 1->2 channel upmixing.
     channel_mixer_->Transform(input_bus, channel_bus_.get());
     // Use the output from the channel mixer as new input bus.
     input_bus = channel_bus_.get();
   }
 
   // Prepare for rendering by calling OnMoreIOData().
   int frames_filled = source_->OnMoreIOData(
       input_bus,
       output_bus_.get(),
@@ skipping 48 matching lines @@
 void WASAPIUnifiedStream::StopAndJoinThread(HRESULT err) {
   CHECK(GetCurrentThreadId() == creating_thread_id_);
   DCHECK(audio_io_thread_.get());
   SetEvent(stop_streaming_event_.Get());
   audio_io_thread_->Join();
   audio_io_thread_.reset();
   HandleError(err);
 }
 
 }  // namespace media