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// Copyright (c) 2012 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_DECRYPTING_AUDIO_DECODER_H_
#define MEDIA_FILTERS_DECRYPTING_AUDIO_DECODER_H_
#include "base/callback.h"
#include "base/memory/ref_counted.h"
#include "media/base/audio_decoder.h"
#include "media/base/decryptor.h"
#include "media/base/demuxer_stream.h"
namespace base {
class MessageLoopProxy;
}
namespace media {
class DecoderBuffer;
class Decryptor;
// Decryptor-based AudioDecoder implementation that can decrypt and decode
// encrypted audio buffers and return decrypted and decompressed audio frames.
// All public APIs and callbacks are trampolined to the |message_loop_| so
// that no locks are required for thread safety.
class MEDIA_EXPORT DecryptingAudioDecoder : public AudioDecoder {
public:
DecryptingAudioDecoder(
const scoped_refptr<base::MessageLoopProxy>& message_loop,
const SetDecryptorReadyCB& set_decryptor_ready_cb);
// AudioDecoder implementation.
virtual void Initialize(const scoped_refptr<DemuxerStream>& stream,
const PipelineStatusCB& status_cb,
const StatisticsCB& statistics_cb) OVERRIDE;
virtual void Read(const ReadCB& read_cb) OVERRIDE;
virtual void Reset(const base::Closure& closure) OVERRIDE;
virtual int bits_per_channel() OVERRIDE;
virtual ChannelLayout channel_layout() OVERRIDE;
virtual int samples_per_second() OVERRIDE;
protected:
virtual ~DecryptingAudioDecoder();
private:
// For a detailed state diagram please see this link: http://goo.gl/8jAok
// TODO(xhwang): Add a ASCII state diagram in this file after this class
// stabilizes.
// TODO(xhwang): Update this diagram for DecryptingAudioDecoder.
enum State {
kUninitialized = 0,
kDecryptorRequested,
kPendingDecoderInit,
kIdle,
kPendingConfigChange,
kPendingDemuxerRead,
kPendingDecode,
kWaitingForKey,
kDecodeFinished,
};
// Carries out the initialization operation scheduled by Initialize().
void DoInitialize(const scoped_refptr<DemuxerStream>& stream,
const PipelineStatusCB& status_cb,
const StatisticsCB& statistics_cb);
// Callback for DecryptorHost::RequestDecryptor().
void SetDecryptor(Decryptor* decryptor);
// Callback for Decryptor::InitializeAudioDecoder() during initialization.
void FinishInitialization(bool success);
// Callback for Decryptor::InitializeAudioDecoder() during config change.
void FinishConfigChange(bool success);
// Carries out the buffer reading operation scheduled by Read().
void DoRead(const ReadCB& read_cb);
void ReadFromDemuxerStream();
// Callback for DemuxerStream::Read().
void DoDecryptAndDecodeBuffer(DemuxerStream::Status status,
const scoped_refptr<DecoderBuffer>& buffer);
void DecodePendingBuffer();
// Callback for Decryptor::DecryptAndDecodeAudio().
void DeliverFrame(int buffer_size,
Decryptor::Status status,
const Decryptor::AudioBuffers& frames);
// Carries out the frame delivery operation scheduled by DeliverFrame().
void DoDeliverFrame(int buffer_size,
Decryptor::Status status,
const Decryptor::AudioBuffers& frames);
// Callback for the |decryptor_| to notify this object that a new key has been
// added.
void OnKeyAdded();
// Resets decoder and calls |reset_cb_|.
void DoReset();
// Sets timestamp and duration for |queued_audio_frames_| to make sure the
// renderer always receives continuous frames without gaps and overlaps.
void EnqueueFrames(const Decryptor::AudioBuffers& frames);
// Converts number of samples to duration.
base::TimeDelta NumberOfSamplesToDuration(int number_of_samples) const;
scoped_refptr<base::MessageLoopProxy> message_loop_;
State state_;
PipelineStatusCB init_cb_;
StatisticsCB statistics_cb_;
ReadCB read_cb_;
base::Closure reset_cb_;
// Pointer to the demuxer stream that will feed us compressed buffers.
scoped_refptr<DemuxerStream> demuxer_stream_;
// Callback to request/cancel decryptor creation notification.
SetDecryptorReadyCB set_decryptor_ready_cb_;
Decryptor* decryptor_;
// The buffer returned by the demuxer that needs decrypting/decoding.
scoped_refptr<media::DecoderBuffer> pending_buffer_to_decode_;
// Indicates the situation where new key is added during pending decode
// (in other words, this variable can only be set in state kPendingDecode).
// If this variable is true and kNoKey is returned then we need to try
// decrypting/decoding again in case the newly added key is the correct
// decryption key.
bool key_added_while_decode_pending_;
Decryptor::AudioBuffers queued_audio_frames_;
// Decoded audio format.
int bits_per_channel_;
ChannelLayout channel_layout_;
int samples_per_second_;
int bytes_per_sample_;
base::TimeDelta output_timestamp_base_;
int total_samples_decoded_;
DISALLOW_COPY_AND_ASSIGN(DecryptingAudioDecoder);
};
} // namespace media
#endif // MEDIA_FILTERS_DECRYPTING_AUDIO_DECODER_H_