Encrypted Media: Enforcing the CDM to decode audio into S16 integers.

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_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:
+  // We do not currently have a way to let the Decrytptor choose the output

[DaleCurtis, 2013/01/10 01:24:35]

s/Decrytptor/Decryptor/

[xhwang, 2013/01/10 18:17:23]

Done.

+  // audio sample format and notify us its choice. Therefore, we require all

[DaleCurtis, 2013/01/10 01:24:35]

s/its/of its/

[xhwang, 2013/01/10 18:17:23]

Done.

+  // Decryptor implementations to decode audio into a fixed integer sample
+  // format with kSupportedBitsPerChannel.

[DaleCurtis, 2013/01/10 01:24:35]

s/with/designated by/

[xhwang, 2013/01/10 18:17:23]

Done.

+  // TODO(xhwang): Remove this restriction after http://crbug.com/169105 fixed.
+  static const int kSupportedBitsPerChannel;
+
   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;
@@ skipping 56 matching lines @@
                       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 audio configs from |demuxer_stream_| and resets
+  // |output_timestamp_base_| and |total_samples_decoded_|.
+  void SetDecoderConfig();
+
   // 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_;
@@ skipping 32 matching lines @@
 
   base::TimeDelta output_timestamp_base_;
   int total_samples_decoded_;
 
   DISALLOW_COPY_AND_ASSIGN(DecryptingAudioDecoder);
 };
 
 }  // namespace media
 
 #endif  // MEDIA_FILTERS_DECRYPTING_AUDIO_DECODER_H_