Implement WebKitClientImpl::loadAudioResource() to decode in-memory audio fil...

media/filters/audio_file_reader.h

+// Copyright (c) 2010 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.
+
+#ifndef MEDIA_FILTERS_AUDIO_FILE_READER_H_
+#define MEDIA_FILTERS_AUDIO_FILE_READER_H_
+
+#include <vector>
+#include "media/filters/ffmpeg_glue.h"
+
+struct AVCodec;
+struct AVCodecContext;
+struct AVFormatContext;
+
+namespace base { class TimeDelta; }
+
+namespace media {
+
+class FFmpegURLProtocol;
+
+class AudioFileReader {
+ public:
+  // Audio file data will be read using the given protocol.
+  // Optionally, NULL may be passed in and SetProtocal() can be called

[scherkus (not reviewing), 2010/12/11 02:31:12]

comment needs updating

[Chris Rogers, 2010/12/13 20:25:27]

Done.

+  // later on before Open() is called.
+  explicit AudioFileReader(FFmpegURLProtocol* protocol);

[scherkus (not reviewing), 2010/12/11 02:31:12]

can you add comment on ownership?  is AudioFileReader responsible for owning the
protocol?  should it?

[Chris Rogers, 2010/12/13 20:25:27]

Done.

+  virtual ~AudioFileReader();
+
+  // Open() reads the audio data format so that the sample_rate(),
+  // channels(), duration(), and number_of_frames() methods can be called.
+  // It returns |true| on success.
+  bool Open();
+  void Close();
+
+  // After a call to Open(), reads |number_of_frames| into |audio_data|.
+  // |audio_data| must be of the same size as channels().
+  // The audio data will be decoded as floating-point linear PCM with
+  // a nominal range of -1.0 -> +1.0.
+  // Returns |true| on success.
+  bool Read(const std::vector<float*>& audio_data, size_t number_of_frames);
+
+  // These methods can be called once Open() has been called.
+  int channels() const;
+  int sample_rate() const;
+  base::TimeDelta duration() const;
+  int64 number_of_frames() const;
+
+ private:
+  FFmpegURLProtocol* protocol_;
+  AVFormatContext* format_context_;
+  AVCodecContext* codec_context_;
+  AVCodec* codec_;
+
+  DISALLOW_COPY_AND_ASSIGN(AudioFileReader);
+};
+
+class InMemoryDataReader : public FFmpegURLProtocol {
+ public:
+  InMemoryDataReader(const char* data, int64 size);

[scherkus (not reviewing), 2010/12/11 02:31:12]

can you add comment on ownership?  is InMemoryDataReader responsible for owning
the data pointer?

I just get a bit nervous seeing data pointers passed around that aren't
scoped_ptr, etc :)

[Chris Rogers, 2010/12/13 20:25:27]

Done.

+
+  virtual int Read(int size, uint8* data);
+  virtual bool GetPosition(int64* position_out);
+  virtual bool SetPosition(int64 position);
+  virtual bool GetSize(int64* size_out);
+  virtual bool IsStreaming();
+
+ private:
+  const char* data_;
+  int64 size_;
+  int64 position_;
+
+  DISALLOW_COPY_AND_ASSIGN(InMemoryDataReader);
+};
+
+}  // namespace media
+
+#endif  // MEDIA_FILTERS_AUDIO_FILE_READER_H_