Added volume adjust sound behind the flag.

media/audio/sounds/wav_audio_handler.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/sounds/wav_audio_handler.h"
 
 #include <algorithm>
 #include <cstring>
 
 #include "base/logging.h"
@@ skipping 21 matching lines @@
 // The offsets of 'fmt' fields.
 const size_t kAudioFormatOffset = 0;
 const size_t kChannelOffset = 2;
 const size_t kSampleRateOffset = 4;
 const size_t kByteRateOffset = 8;
 const size_t kBitsPerSampleOffset = 14;
 
 // Some constants for audio format.
 const int kAudioFormatPCM = 1;
 
+// The number of frames each OnMoreData() call will request.
+const int kDefaultFrameCount = 1024;
+
 // Reads an integer from |data| with |offset|.
-template<typename T> T ReadInt(const base::StringPiece& data, size_t offset) {
+template <typename T>
+T ReadInt(const base::StringPiece& data, size_t offset) {
   CHECK_LE(offset + sizeof(T), data.size());
   T result;
   memcpy(&result, data.data() + offset, sizeof(T));
 #if !defined(ARCH_CPU_LITTLE_ENDIAN)
   result = base::ByteSwap(result);
 #endif
   return result;
 }
 
 }  // namespace
 
 namespace media {
 
-WavAudioHandler::WavAudioHandler(const base::StringPiece& wav_data)
-    : num_channels_(0),
-      sample_rate_(0),
-      byte_rate_(0),
-      bits_per_sample_(0) {
+WavAudioHandler::WavAudioHandler(const base::StringPiece& wav_data) {
   CHECK_LE(kWavFileHeaderSize, wav_data.size()) << "wav data is too small";
   CHECK(wav_data.starts_with(kChunkId) &&
         memcmp(wav_data.data() + 8, kFormat, 4) == 0)
       << "incorrect wav header";
 
   uint32 total_length = std::min(ReadInt<uint32>(wav_data, 4),
                                  static_cast<uint32>(wav_data.size()));
   uint32 offset = kWavFileHeaderSize;
   while (offset < total_length) {
     const int length = ParseSubChunk(wav_data.substr(offset));
     CHECK_LE(0, length) << "can't parse wav sub-chunk";
     offset += length;
   }
+
+  const int64 size = data_.size();

[DaleCurtis, 2013/12/18 21:20:21]

If you set AudioBuffer::frames_per_buffer = data_.size() / (channels *
bytes_per_sample), the duration returned by AudioParameters::GetBufferDuration
should match this calculation.

[ygorshenin1, 2013/12/19 15:42:29]

frames_per_buffer is used in creation of AudioStreamProxy, and when the change
you proposed is applied, volume up/down sound becomes very harsh. I'd prefer to
use kDefaultFrameCount here.

[DaleCurtis, 2013/12/19 19:44:08]

Yes, you shouldn't use the AudioParameters directly from WavAudioHandler in
stream creation.  AudioStreamHandler should choose its own buffer size, it can
copy the rest of these parameters though.

[ygorshenin1, 2013/12/20 09:05:05]

Done.

+  const int64 rate = params_.GetBytesPerSecond();
+  if (rate)
+    duration_ = base::TimeDelta::FromMicroseconds(size * 1000000 / rate);
 }
 
-WavAudioHandler::~WavAudioHandler() {
-}
+WavAudioHandler::~WavAudioHandler() {}
 
 bool WavAudioHandler::AtEnd(size_t cursor) const {
   return data_.size() <= cursor;
 }
 
 bool WavAudioHandler::CopyTo(AudioBus* bus,
                              size_t cursor,
                              size_t* bytes_written) const {
   if (!bus)
     return false;
-  if (bus->channels() != num_channels_) {
-    LOG(ERROR) << "Number of channel mismatch.";
+  if (bus->channels() != params_.channels()) {
+    VLOG(1) << "Number of channel mismatch.";
     return false;
   }
   if (AtEnd(cursor)) {
     bus->Zero();
     return true;
   }
-  const int remaining_frames = (data_.size() - cursor) / bytes_per_frame_;
+  const int remaining_frames =
+      (data_.size() - cursor) / params_.GetBytesPerFrame();
   const int frames = std::min(bus->frames(), remaining_frames);
-  bus->FromInterleaved(data_.data() + cursor, frames, bytes_per_sample_);
-  *bytes_written = frames * bytes_per_frame_;
+  bus->FromInterleaved(data_.data() + cursor, frames,
+                       params_.bits_per_sample() >> 3);

[DaleCurtis, 2013/12/18 21:20:21]

Just use * 8, the compiler will optimize as necessary.

[ygorshenin1, 2013/12/19 15:42:29]

Done.

+  *bytes_written = frames * params_.GetBytesPerFrame();
   bus->ZeroFramesPartial(frames, bus->frames() - frames);
   return true;
 }
 
 int WavAudioHandler::ParseSubChunk(const base::StringPiece& data) {
   if (data.size() < kChunkHeaderSize)
     return data.size();
   uint32 chunk_length = ReadInt<uint32>(data, 4);
   if (data.starts_with(kSubchunk1Id)) {
     if (!ParseFmtChunk(data.substr(kChunkHeaderSize, chunk_length)))
       return -1;
   } else if (data.starts_with(kSubchunk2Id)) {
     if (!ParseDataChunk(data.substr(kChunkHeaderSize, chunk_length)))
       return -1;
   } else {
     LOG(ERROR) << "Unknown data chunk: " << data.substr(0, 4) << ".";
   }
   return chunk_length + kChunkHeaderSize;
 }
 
 bool WavAudioHandler::ParseFmtChunk(const base::StringPiece& data) {
   if (data.size() < kFmtChunkMinimumSize) {
     LOG(ERROR) << "Data size " << data.size() << " is too short.";
     return false;
   }
   DCHECK_EQ(ReadInt<uint16>(data, kAudioFormatOffset), kAudioFormatPCM);
-  num_channels_ = ReadInt<uint16>(data, kChannelOffset);
-  sample_rate_ = ReadInt<uint32>(data, kSampleRateOffset);
-  byte_rate_ = ReadInt<uint32>(data, kByteRateOffset);
-  bits_per_sample_ = ReadInt<uint16>(data, kBitsPerSampleOffset);
-  bytes_per_sample_ = bits_per_sample_ >> 3;
-  bytes_per_frame_ = num_channels_ * bytes_per_sample_;
+  int num_channels = ReadInt<uint16>(data, kChannelOffset);
+  int sample_rate = ReadInt<uint32>(data, kSampleRateOffset);
+  int bits_per_sample = ReadInt<uint16>(data, kBitsPerSampleOffset);
+  params_ = AudioParameters(AudioParameters::AUDIO_PCM_LOW_LATENCY,
+                            GuessChannelLayout(num_channels),
+                            sample_rate,
+                            bits_per_sample,
+                            kDefaultFrameCount);
   return true;
 }
 
 bool WavAudioHandler::ParseDataChunk(const base::StringPiece& data) {
   data_ = data;
   return true;
 }
 
 }  // namespace media