Support 8 and 32 bit formats for Mac Channel Swizzler.

media/audio/mac/audio_output_mac.cc

 // Copyright (c) 2009 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_manager_mac.h"
 #include "media/audio/mac/audio_output_mac.h"
 
 #include "base/basictypes.h"
 #include "base/logging.h"
 #include "media/audio/audio_util.h"
@@ skipping 151 matching lines @@
 void PCMQueueOutAudioOutputStream::GetVolume(double* left_level,
                                              double* right_level) {
   if (!audio_queue_)
     return;
   *left_level = volume_;
   *right_level = volume_;
 }
 
 // Reorder PCM from AAC layout to Core Audio layout.
 // TODO(fbarchard): Switch layout when ffmpeg is updated.
-const int kNumSurroundChannels = 6;
+namespace {
 template<class Format>
 static void SwizzleLayout(Format *b, size_t filled) {
+  static const int kNumSurroundChannels = 6;
   Format aac[kNumSurroundChannels];
   for (size_t i = 0; i < filled; i += sizeof(aac), b += kNumSurroundChannels) {
     memcpy(aac, b, sizeof(aac));
     b[0] = aac[1];  // L
     b[1] = aac[2];  // R
     b[2] = aac[0];  // C
     b[3] = aac[5];  // LFE
     b[4] = aac[3];  // Ls
     b[5] = aac[4];  // Rs
   }
 }
+}  // namespace
 
 // Note to future hackers of this function: Do not add locks here because we
 // call out to third party source that might do crazy things including adquire
 // external locks or somehow re-enter here because its legal for them to call
 // some audio functions.
 void PCMQueueOutAudioOutputStream::RenderCallback(void* p_this,
                                                   AudioQueueRef queue,
                                                   AudioQueueBufferRef buffer) {
   PCMQueueOutAudioOutputStream* audio_stream =
       static_cast<PCMQueueOutAudioOutputStream*>(p_this);
@@ skipping 15 matching lines @@
   if (!filled) {
     CHECK(audio_stream->silence_bytes_ <= static_cast<int>(capacity));
     filled = audio_stream->silence_bytes_;
     memset(buffer->mAudioData, 0, filled);
   } else if (filled > capacity) {
     // User probably overran our buffer.
     audio_stream->HandleError(0);
     return;
   }
 
-  // Handle channel order for PCM 5.1 audio.
+  // Handle channel order for 5.1 audio.
   if (audio_stream->format_.mChannelsPerFrame == 6) {
     if (audio_stream->format_.mBitsPerChannel == 8) {
       SwizzleLayout(reinterpret_cast<uint8*>(buffer->mAudioData), filled);
     } else if (audio_stream->format_.mBitsPerChannel == 16) {
       SwizzleLayout(reinterpret_cast<int16*>(buffer->mAudioData), filled);
     } else if (audio_stream->format_.mBitsPerChannel == 32) {
       SwizzleLayout(reinterpret_cast<int32*>(buffer->mAudioData), filled);
     }
   }
 
@@ skipping 34 matching lines @@
       return;
     }
   }
   err  = AudioQueueStart(audio_queue_, NULL);
   if (err != noErr) {
     HandleError(err);
     return;
   }
 }