// Copyright (c) 2011 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 "base/basictypes.h"
#include "base/memory/scoped_ptr.h"
#include "media/base/media_export.h"
struct AVCodecContext;
namespace base { class TimeDelta; }
namespace media {
class AudioBus;
class FFmpegGlue;
class FFmpegURLProtocol;
class MEDIA_EXPORT AudioFileReader {
public:
// Audio file data will be read using the given protocol.
// The AudioFileReader does not take ownership of |protocol| and
// simply maintains a weak reference to it.
explicit AudioFileReader(FFmpegURLProtocol* protocol);
virtual ~AudioFileReader();
// Open() reads the audio data format so that the sample_rate(),
// channels(), GetDuration(), and GetNumberOfFrames() methods can be called.
// It returns |true| on success.
bool Open();
void Close();
// After a call to Open(), attempts to fully fill |audio_bus| with decoded
// audio data. Any unfilled frames will be zeroed out.
// |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 the number of sample-frames actually read which will always be
// <= audio_bus->frames()
int Read(AudioBus* audio_bus);
// These methods can be called once Open() has been called.
int channels() const { return channels_; }
int sample_rate() const { return sample_rate_; }
// Please note that GetDuration() and GetNumberOfFrames() attempt to be
// accurate, but are only estimates. For some encoded formats, the actual
// duration of the file can only be determined once all the file data has been
// read. The Read() method returns the actual number of sample-frames it has
// read.
base::TimeDelta GetDuration() const;
int GetNumberOfFrames() const;
private:
scoped_ptr<FFmpegGlue> glue_;
AVCodecContext* codec_context_;
int stream_index_;
FFmpegURLProtocol* protocol_;
int channels_;
int sample_rate_;
// AVSampleFormat initially requested; not Chrome's SampleFormat.
int av_sample_format_;
DISALLOW_COPY_AND_ASSIGN(AudioFileReader);
};
} // namespace media
#endif // MEDIA_FILTERS_AUDIO_FILE_READER_H_