Add DecryptingAudioDecoder.

media/filters/decrypting_audio_decoder.h

 // 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_VIDEO_DECODER_H_
-#define MEDIA_FILTERS_DECRYPTING_VIDEO_DECODER_H_
+#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"
-#include "media/base/video_decoder.h"
 
 namespace base {
 class MessageLoopProxy;
 }
 
 namespace media {
 
 class DecoderBuffer;
 class Decryptor;
 
-// Decryptor-based VideoDecoder implementation that can decrypt and decode
-// encrypted video buffers and return decrypted and decompressed video frames.
+// 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.
 //
-// TODO(xhwang): For now, DecryptingVideoDecoder relies on the decryptor to do
-// both decryption and video decoding. Add the path to use the decryptor for
-// decryption only and use other VideoDecoder implementations within
-// DecryptingVideoDecoder for video decoding.
-class MEDIA_EXPORT DecryptingVideoDecoder : public VideoDecoder {
+// TODO(xhwang): For now, DecryptingAudioDecoder relies on the decryptor to do
+// both decryption and audio decoding. Add the path to use the decryptor for
+// decryption only and use other AudioDecoder implementations within
+// DecryptingAudioDecoder for audio decoding.
+class MEDIA_EXPORT DecryptingAudioDecoder : public AudioDecoder {
  public:
   // Callback to get a message loop.
   typedef base::Callback<
       scoped_refptr<base::MessageLoopProxy>()> MessageLoopFactoryCB;
   // Callback to notify decryptor creation.
   typedef base::Callback<void(Decryptor*)> DecryptorNotificationCB;
   // Callback to request/cancel decryptor creation notification.
   // Calling this callback with a non-null callback registers decryptor creation
   // notification. When the decryptor is created, notification will be sent
   // through the provided callback.
   // Calling this callback with a null callback cancels previously registered
   // decryptor creation notification. Any previously provided callback will be
   // fired immediately with NULL.
   typedef base::Callback<void(const DecryptorNotificationCB&)>
       RequestDecryptorNotificationCB;
 
-  DecryptingVideoDecoder(
+  DecryptingAudioDecoder(
       const MessageLoopFactoryCB& message_loop_factory_cb,
       const RequestDecryptorNotificationCB& request_decryptor_notification_cb);
 
-  // VideoDecoder implementation.
+  // 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 void Stop(const base::Closure& closure) OVERRIDE;
+  virtual int bits_per_channel() OVERRIDE;
+  virtual ChannelLayout channel_layout() OVERRIDE;
+  virtual int samples_per_second() OVERRIDE;
+
+  // TODO(xhwang): Either remove Stop() here or add Stop() to AudioDecoder
+  // interface. Figure out the right teardown process.
+  void Stop(const base::Closure& closure);

[xhwang, 2012/10/18 02:14:10]

scherkus: currently nobody is gonna call this Stop(). Are we okay with this
during teardown? It's seems working for now since AudioDecoder is refcounted.
WDYT?

 
  protected:
-  virtual ~DecryptingVideoDecoder();
+  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.
   enum DecoderState {
     kUninitialized = 0,
     kDecryptorRequested,
     kPendingDecoderInit,
     kIdle,
     kPendingDemuxerRead,
     kPendingDecode,
     kWaitingForKey,
     kDecodeFinished,
     kStopped
   };
 
   // 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::InitializeVideoDecoder().
+  // Callback for Decryptor::InitializeAudioDecoder().
   void FinishInitialization(bool success);
 
   // Carries out the buffer reading operation scheduled by Read().
   void DoRead(const ReadCB& read_cb);
 
   void ReadFromDemuxerStream();
 
   // Callback for DemuxerStream::Read().
   void DecryptAndDecodeBuffer(DemuxerStream::Status status,
                               const scoped_refptr<DecoderBuffer>& buffer);
 
   // Carries out the buffer decrypting/decoding operation scheduled by
   // DecryptAndDecodeBuffer().
   void DoDecryptAndDecodeBuffer(DemuxerStream::Status status,
                                 const scoped_refptr<DecoderBuffer>& buffer);
 
   void DecodePendingBuffer();
 
-  // Callback for Decryptor::DecryptAndDecodeVideo().
+  // Callback for Decryptor::DecryptAndDecodeAudio().
   void DeliverFrame(int buffer_size,
                     Decryptor::Status status,
-                    const scoped_refptr<VideoFrame>& frame);
+                    const Decryptor::AudioBuffers& frames);
 
   // Carries out the frame delivery operation scheduled by DeliverFrame().
   void DoDeliverFrame(int buffer_size,
                       Decryptor::Status status,
-                      const scoped_refptr<VideoFrame>& frame);
+                      const Decryptor::AudioBuffers& frames);
 
-  // Callback for the |decryptor_| to notify the DecryptingVideoDecoder that
+  // Callback for the |decryptor_| to notify the DecryptingAudioDecoder that
   // a new key has been added.
   void OnKeyAdded();
 
   // Reset decoder and call |reset_cb_|.
   void DoReset();
 
   // Free decoder resources and call |stop_cb_|.
   void DoStop();
 
   // This is !is_null() iff Initialize() hasn't been called.
   MessageLoopFactoryCB message_loop_factory_cb_;
 
   scoped_refptr<base::MessageLoopProxy> message_loop_;
 
-  // Current state of the DecryptingVideoDecoder.
+  // Current state of the DecryptingAudioDecoder.
   DecoderState state_;
 
   PipelineStatusCB init_cb_;
   StatisticsCB statistics_cb_;
   ReadCB read_cb_;
   base::Closure reset_cb_;
   base::Closure stop_cb_;
 
   // Pointer to the demuxer stream that will feed us compressed buffers.
   scoped_refptr<DemuxerStream> demuxer_stream_;
 
   // Callback to request/cancel decryptor creation notification.
   RequestDecryptorNotificationCB request_decryptor_notification_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_pending_decode_;
 
-  DISALLOW_COPY_AND_ASSIGN(DecryptingVideoDecoder);
+  Decryptor::AudioBuffers queued_audio_frames_;
+
+  // Decoded audio format.
+  int bits_per_channel_;
+  ChannelLayout channel_layout_;
+  int samples_per_second_;
+
+  DISALLOW_COPY_AND_ASSIGN(DecryptingAudioDecoder);
 };
 
 }  // namespace media
 
-#endif  // MEDIA_FILTERS_DECRYPTING_VIDEO_DECODER_H_
+#endif  // MEDIA_FILTERS_DECRYPTING_AUDIO_DECODER_H_