decrypting_video_decoder.h revision 5d1f7b1de12d16ceb2c938c56701a3e8bfa558f7 
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
14namespace base {
15class SingleThreadTaskRunner;
16}
17
18namespace media {
19
20class DecoderBuffer;
21class Decryptor;
22
23// Decryptor-based VideoDecoder implementation that can decrypt and decode
24// encrypted video buffers and return decrypted and decompressed video frames.
25// All public APIs and callbacks are trampolined to the |task_runner_| so
26// that no locks are required for thread safety.
27class MEDIA_EXPORT DecryptingVideoDecoder : public VideoDecoder {
28 public:
29  DecryptingVideoDecoder(
30      const scoped_refptr<base::SingleThreadTaskRunner>& task_runner,
31      const SetDecryptorReadyCB& set_decryptor_ready_cb);
32  virtual ~DecryptingVideoDecoder();
33
34  // VideoDecoder implementation.
35  virtual void Initialize(const VideoDecoderConfig& config,
36                          const PipelineStatusCB& status_cb) OVERRIDE;
37  virtual void Decode(const scoped_refptr<DecoderBuffer>& buffer,
38                      const DecodeCB& decode_cb) OVERRIDE;
39  virtual void Reset(const base::Closure& closure) OVERRIDE;
40  virtual void Stop(const base::Closure& closure) OVERRIDE;
41
42 private:
43  // For a detailed state diagram please see this link: http://goo.gl/8jAok
44  // TODO(xhwang): Add a ASCII state diagram in this file after this class
45  // stabilizes.
46  enum State {
47    kUninitialized = 0,
48    kDecryptorRequested,
49    kPendingDecoderInit,
50    kIdle,
51    kPendingDecode,
52    kWaitingForKey,
53    kDecodeFinished,
54    kStopped,
55    kError
56  };
57
58  // Callback for DecryptorHost::RequestDecryptor().
59  void SetDecryptor(Decryptor* decryptor);
60
61  // Callback for Decryptor::InitializeVideoDecoder() during initialization.
62  void FinishInitialization(bool success);
63
64  void DecodePendingBuffer();
65
66  // Callback for Decryptor::DecryptAndDecodeVideo().
67  void DeliverFrame(int buffer_size,
68                    Decryptor::Status status,
69                    const scoped_refptr<VideoFrame>& frame);
70
71  // Callback for the |decryptor_| to notify this object that a new key has been
72  // added.
73  void OnKeyAdded();
74
75  // Reset decoder and call |reset_cb_|.
76  void DoReset();
77
78  // Free decoder resources and call |stop_cb_|.
79  void DoStop();
80
81  scoped_refptr<base::SingleThreadTaskRunner> task_runner_;
82  base::WeakPtrFactory<DecryptingVideoDecoder> weak_factory_;
83  base::WeakPtr<DecryptingVideoDecoder> weak_this_;
84
85  State state_;
86
87  PipelineStatusCB init_cb_;
88  DecodeCB decode_cb_;
89  base::Closure reset_cb_;
90
91  VideoDecoderConfig config_;
92
93  // Callback to request/cancel decryptor creation notification.
94  SetDecryptorReadyCB set_decryptor_ready_cb_;
95
96  Decryptor* decryptor_;
97
98  // The buffer that needs decrypting/decoding.
99  scoped_refptr<media::DecoderBuffer> pending_buffer_to_decode_;
100
101  // Indicates the situation where new key is added during pending decode
102  // (in other words, this variable can only be set in state kPendingDecode).
103  // If this variable is true and kNoKey is returned then we need to try
104  // decrypting/decoding again in case the newly added key is the correct
105  // decryption key.
106  bool key_added_while_decode_pending_;
107
108  // A unique ID to trace Decryptor::DecryptAndDecodeVideo() call and the
109  // matching DecryptCB call (in DoDeliverFrame()).
110  uint32 trace_id_;
111
112  DISALLOW_COPY_AND_ASSIGN(DecryptingVideoDecoder);
113};
114
115}  // namespace media
116
117#endif  // MEDIA_FILTERS_DECRYPTING_VIDEO_DECODER_H_
118