1 files changed, 94 insertions, 0 deletions
diff --git a/chromium/content/renderer/media/audio_decoder.cc b/chromium/content/renderer/media/audio_decoder.cc
new file mode 100644
index 00000000000..64cf6ddde73
--- /dev/null
+++ b/chromium/content/renderer/media/audio_decoder.cc
@@ -0,0 +1,94 @@
+// 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 "content/renderer/media/audio_decoder.h"
+
+#include <vector>
+
+#include "base/basictypes.h"
+#include "base/strings/string_util.h"
+#include "base/time/time.h"
+#include "media/base/audio_bus.h"
+#include "media/base/limits.h"
+#include "media/filters/audio_file_reader.h"
+#include "media/filters/in_memory_url_protocol.h"
+#include "third_party/WebKit/public/platform/WebAudioBus.h"
+
+using media::AudioBus;
+using media::AudioFileReader;
+using media::InMemoryUrlProtocol;
+using std::vector;
+using WebKit::WebAudioBus;
+
+namespace content {
+
+// Decode in-memory audio file data.
+bool DecodeAudioFileData(
+    WebKit::WebAudioBus* destination_bus,
+    const char* data, size_t data_size, double sample_rate) {
+  DCHECK(destination_bus);
+  if (!destination_bus)
+    return false;
+
+  // Uses the FFmpeg library for audio file reading.
+  InMemoryUrlProtocol url_protocol(reinterpret_cast<const uint8*>(data),
+                                   data_size, false);
+  AudioFileReader reader(&url_protocol);
+
+  if (!reader.Open())
+    return false;
+
+  size_t number_of_channels = reader.channels();
+  double file_sample_rate = reader.sample_rate();
+  size_t number_of_frames = static_cast<size_t>(reader.number_of_frames());
+
+  // Apply sanity checks to make sure crazy values aren't coming out of
+  // FFmpeg.
+  if (!number_of_channels ||
+      number_of_channels > static_cast<size_t>(media::limits::kMaxChannels) ||
+      file_sample_rate < media::limits::kMinSampleRate ||
+      file_sample_rate > media::limits::kMaxSampleRate)
+    return false;
+
+  // Allocate and configure the output audio channel data.
+  destination_bus->initialize(number_of_channels,
+                              number_of_frames,
+                              file_sample_rate);
+
+  // Wrap the channel pointers which will receive the decoded PCM audio.
+  vector<float*> audio_data;
+  audio_data.reserve(number_of_channels);
+  for (size_t i = 0; i < number_of_channels; ++i) {
+    audio_data.push_back(destination_bus->channelData(i));
+  }
+
+  scoped_ptr<AudioBus> audio_bus = AudioBus::WrapVector(
+      number_of_frames, audio_data);
+
+  // Decode the audio file data.
+  // TODO(crogers): If our estimate was low, then we still may fail to read
+  // all of the data from the file.
+  size_t actual_frames = reader.Read(audio_bus.get());
+
+  // Adjust WebKit's bus to account for the actual file length
+  // and valid data read.
+  if (actual_frames != number_of_frames) {
+    DCHECK_LE(actual_frames, number_of_frames);
+    destination_bus->resizeSmaller(actual_frames);
+  }
+
+  double duration = actual_frames / file_sample_rate;
+
+  DVLOG(1) << "Decoded file data -"
+           << " data: " << data
+           << " data size: " << data_size
+           << " duration: " << duration
+           << " number of frames: " << actual_frames
+           << " sample rate: " << file_sample_rate
+           << " number of channels: " << number_of_channels;
+
+  return actual_frames > 0;
+}
+
+}  // namespace content