Add DecryptingAudioDecoder.

media/filters/decrypting_audio_decoder.h

Index: media/filters/decrypting_audio_decoder.h
diff --git a/media/filters/decrypting_video_decoder.h b/media/filters/decrypting_audio_decoder.h
similarity index 75%
copy from media/filters/decrypting_video_decoder.h
copy to media/filters/decrypting_audio_decoder.h
index 900b0bb3db9e8a1c74b620bea286329df2d5fc85..769b3cb73c290dd9312169876f03f98f61426658 100644
--- a/media/filters/decrypting_video_decoder.h
+++ b/media/filters/decrypting_audio_decoder.h
@@ -2,14 +2,14 @@
 // 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;
@@ -20,16 +20,16 @@ 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<
@@ -46,25 +46,28 @@ class MEDIA_EXPORT DecryptingVideoDecoder : public VideoDecoder {
   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;
 
  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.
+  // TODO(xhwang): Update this diagram for DecryptingAudioDecoder.
   enum DecoderState {
     kUninitialized = 0,
     kDecryptorRequested,
@@ -74,7 +77,6 @@ class MEDIA_EXPORT DecryptingVideoDecoder : public VideoDecoder {
     kPendingDecode,
     kWaitingForKey,
     kDecodeFinished,
-    kStopped
   };
 
   // Carries out the initialization operation scheduled by Initialize().
@@ -85,7 +87,7 @@ class MEDIA_EXPORT DecryptingVideoDecoder : public VideoDecoder {
   // 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().
@@ -104,32 +106,29 @@ class MEDIA_EXPORT DecryptingVideoDecoder : public VideoDecoder {
 
   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_;
@@ -155,9 +154,16 @@ class MEDIA_EXPORT DecryptingVideoDecoder : public VideoDecoder {
   // decryption key.
   bool key_added_while_pending_decode_;
 
-  DISALLOW_COPY_AND_ASSIGN(DecryptingVideoDecoder);
+  Decryptor::AudioBuffers queued_audio_frames_;

[scherkus (not reviewing), 2012/10/19 02:12:58]

sorry just for noticing this... why are we queuing audio frames again?

[xhwang, 2012/10/19 02:19:45]

This is the same as "queued_audio_" in FFAD. We may have multiple buffers
returned for one DecryptAndDecode call. But we only have one read cb pending. So
we'll satisfy the read cb with one buffer and queue the rest for future Read
calls.

+
+  // 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_