media/filters/decrypting_video_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_VIDEO_DECODER_H_
   6 #define MEDIA_FILTERS_DECRYPTING_VIDEO_DECODER_H_
   7
   8 #include "base/callback.h"
   9 #include "base/memory/weak_ptr.h"
  10 #include "media/base/decryptor.h"
  11 #include "media/base/video_decoder.h"
  12 #include "media/base/video_decoder_config.h"
  13
  14 namespace base {
  15 class SingleThreadTaskRunner;
  16 }
  17
  18 namespace media {
  19
  20 class DecoderBuffer;
  21 class Decryptor;
  22 class MediaLog;
  23
  24 // Decryptor-based VideoDecoder implementation that can decrypt and decode
  25 // encrypted video buffers and return decrypted and decompressed video frames.
  26 // All public APIs and callbacks are trampolined to the |task_runner_| so
  27 // that no locks are required for thread safety.
  28 class MEDIA_EXPORT DecryptingVideoDecoder : public VideoDecoder {
  29  public:
  30   DecryptingVideoDecoder(
  31       const scoped_refptr<base::SingleThreadTaskRunner>& task_runner,
  32       const scoped_refptr<MediaLog>& media_log,
  33       const SetDecryptorReadyCB& set_decryptor_ready_cb,
  34       const base::Closure& waiting_for_decryption_key_cb);
  35   ~DecryptingVideoDecoder() override;
  36
  37   // VideoDecoder implementation.
  38   std::string GetDisplayName() const override;
  39   void Initialize(const VideoDecoderConfig& config,
  40                   bool low_delay,
  41                   const InitCB& init_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   static const char kDecoderName[];
  48
  49  private:
  50   // For a detailed state diagram please see this link: http://goo.gl/8jAok
  51   // TODO(xhwang): Add a ASCII state diagram in this file after this class
  52   // stabilizes.
  53   enum State {
  54     kUninitialized = 0,
  55     kDecryptorRequested,
  56     kPendingDecoderInit,
  57     kIdle,
  58     kPendingDecode,
  59     kWaitingForKey,
  60     kDecodeFinished,
  61     kError
  62   };
  63
  64   // Callback for DecryptorHost::RequestDecryptor(). |decryptor_attached_cb| is
  65   // called when the decryptor has been completely attached to the pipeline.
  66   void SetDecryptor(Decryptor* decryptor,
  67                     const DecryptorAttachedCB& decryptor_attached_cb);
  68
  69   // Callback for Decryptor::InitializeVideoDecoder() during initialization.
  70   void FinishInitialization(bool success);
  71
  72   void DecodePendingBuffer();
  73
  74   // Callback for Decryptor::DecryptAndDecodeVideo().
  75   void DeliverFrame(int buffer_size,
  76                     Decryptor::Status status,
  77                     const scoped_refptr<VideoFrame>& frame);
  78
  79   // Callback for the |decryptor_| to notify this object that a new key has been
  80   // added.
  81   void OnKeyAdded();
  82
  83   // Reset decoder and call |reset_cb_|.
  84   void DoReset();
  85
  86   scoped_refptr<base::SingleThreadTaskRunner> task_runner_;
  87
  88   scoped_refptr<MediaLog> media_log_;
  89
  90   State state_;
  91
  92   InitCB init_cb_;
  93   OutputCB output_cb_;
  94   DecodeCB decode_cb_;
  95   base::Closure reset_cb_;
  96   base::Closure waiting_for_decryption_key_cb_;
  97
  98   VideoDecoderConfig config_;
  99
 100   // Callback to request/cancel decryptor creation notification.
 101   SetDecryptorReadyCB set_decryptor_ready_cb_;
 102
 103   Decryptor* decryptor_;
 104
 105   // The buffer that needs decrypting/decoding.
 106   scoped_refptr<media::DecoderBuffer> pending_buffer_to_decode_;
 107
 108   // Indicates the situation where new key is added during pending decode
 109   // (in other words, this variable can only be set in state kPendingDecode).
 110   // If this variable is true and kNoKey is returned then we need to try
 111   // decrypting/decoding again in case the newly added key is the correct
 112   // decryption key.
 113   bool key_added_while_decode_pending_;
 114
 115   // A unique ID to trace Decryptor::DecryptAndDecodeVideo() call and the
 116   // matching DecryptCB call (in DoDeliverFrame()).
 117   uint32 trace_id_;
 118
 119   base::WeakPtr<DecryptingVideoDecoder> weak_this_;
 120   base::WeakPtrFactory<DecryptingVideoDecoder> weak_factory_;
 121
 122   DISALLOW_COPY_AND_ASSIGN(DecryptingVideoDecoder);
 123 };
 124
 125 }  // namespace media
 126
 127 #endif  // MEDIA_FILTERS_DECRYPTING_VIDEO_DECODER_H_