media/filters/decrypting_audio_decoder.h

   1 // Copyright (c) 2012 The Chromium Authors. All rights reserved.
   2 // Use of this source code is governed by a BSD-style license that can be
   3 // found in the LICENSE file.
   4
   5 #ifndef MEDIA_FILTERS_DECRYPTING_AUDIO_DECODER_H_
   6 #define MEDIA_FILTERS_DECRYPTING_AUDIO_DECODER_H_
   7
   8 #include "base/callback.h"
   9 #include "base/memory/ref_counted.h"
  10 #include "base/memory/scoped_ptr.h"
  11 #include "base/memory/weak_ptr.h"
  12 #include "base/time/time.h"
  13 #include "media/base/audio_decoder.h"
  14 #include "media/base/decryptor.h"
  15 #include "media/base/demuxer_stream.h"
  16
  17 namespace base {
  18 class SingleThreadTaskRunner;
  19 }
  20
  21 namespace media {
  22
  23 class AudioTimestampHelper;
  24 class DecoderBuffer;
  25 class Decryptor;
  26
  27 // Decryptor-based AudioDecoder implementation that can decrypt and decode
  28 // encrypted audio buffers and return decrypted and decompressed audio frames.
  29 // All public APIs and callbacks are trampolined to the |task_runner_| so
  30 // that no locks are required for thread safety.
  31 class MEDIA_EXPORT DecryptingAudioDecoder : public AudioDecoder {
  32  public:
  33   DecryptingAudioDecoder(
  34       const scoped_refptr<base::SingleThreadTaskRunner>& task_runner,
  35       const SetDecryptorReadyCB& set_decryptor_ready_cb);
  36   ~DecryptingAudioDecoder() override;
  37
  38   // AudioDecoder implementation.
  39   std::string GetDisplayName() const override;
  40   void Initialize(const AudioDecoderConfig& config,
  41                   const PipelineStatusCB& status_cb,
  42                   const OutputCB& output_cb) override;
  43   void Decode(const scoped_refptr<DecoderBuffer>& buffer,
  44               const DecodeCB& decode_cb) override;
  45   void Reset(const base::Closure& closure) override;
  46
  47  private:
  48   // For a detailed state diagram please see this link: http://goo.gl/8jAok
  49   // TODO(xhwang): Add a ASCII state diagram in this file after this class
  50   // stabilizes.
  51   // TODO(xhwang): Update this diagram for DecryptingAudioDecoder.
  52   enum State {
  53     kUninitialized = 0,
  54     kDecryptorRequested,
  55     kPendingDecoderInit,
  56     kIdle,
  57     kPendingDecode,
  58     kWaitingForKey,
  59     kDecodeFinished,
  60     kError
  61   };
  62
  63   // Callback for DecryptorHost::RequestDecryptor(). |decryptor_attached_cb| is
  64   // called when the decryptor has been completely attached to the pipeline.
  65   void SetDecryptor(Decryptor* decryptor,
  66                     const DecryptorAttachedCB& decryptor_attached_cb);
  67
  68   // Initializes the audio decoder on the |decryptor_| with |config_|.
  69   void InitializeDecoder();
  70
  71   // Callback for Decryptor::InitializeAudioDecoder() during initialization.
  72   void FinishInitialization(bool success);
  73
  74   void DecodePendingBuffer();
  75
  76   // Callback for Decryptor::DecryptAndDecodeAudio().
  77   void DeliverFrame(int buffer_size,
  78                     Decryptor::Status status,
  79                     const Decryptor::AudioFrames& frames);
  80
  81   // Callback for the |decryptor_| to notify this object that a new key has been
  82   // added.
  83   void OnKeyAdded();
  84
  85   // Resets decoder and calls |reset_cb_|.
  86   void DoReset();
  87
  88   // Sets timestamps for |frames| and then passes them to |output_cb_|.
  89   void ProcessDecodedFrames(const Decryptor::AudioFrames& frames);
  90
  91   scoped_refptr<base::SingleThreadTaskRunner> task_runner_;
  92
  93   State state_;
  94
  95   PipelineStatusCB init_cb_;
  96   OutputCB output_cb_;
  97   DecodeCB decode_cb_;
  98   base::Closure reset_cb_;
  99
 100   // The current decoder configuration.
 101   AudioDecoderConfig config_;
 102
 103   // Callback to request/cancel decryptor creation notification.
 104   SetDecryptorReadyCB set_decryptor_ready_cb_;
 105
 106   Decryptor* decryptor_;
 107
 108   // The buffer that needs decrypting/decoding.
 109   scoped_refptr<media::DecoderBuffer> pending_buffer_to_decode_;
 110
 111   // Indicates the situation where new key is added during pending decode
 112   // (in other words, this variable can only be set in state kPendingDecode).
 113   // If this variable is true and kNoKey is returned then we need to try
 114   // decrypting/decoding again in case the newly added key is the correct
 115   // decryption key.
 116   bool key_added_while_decode_pending_;
 117
 118   scoped_ptr<AudioTimestampHelper> timestamp_helper_;
 119
 120   base::WeakPtr<DecryptingAudioDecoder> weak_this_;
 121   base::WeakPtrFactory<DecryptingAudioDecoder> weak_factory_;
 122
 123   DISALLOW_COPY_AND_ASSIGN(DecryptingAudioDecoder);
 124 };
 125
 126 }  // namespace media
 127
 128 #endif  // MEDIA_FILTERS_DECRYPTING_AUDIO_DECODER_H_