1
    2
    3
    4
    5
    6
    7
    8
    9
   10
   11
   12
   13
   14
   15
   16
   17
   18
   19
   20
   21
   22
   23
   24
   25
   26
   27
   28
   29
   30
   31
   32
   33
   34
   35
   36
   37
   38
   39
   40
   41
   42
   43
   44
   45
   46
   47
   48
   49
   50
   51
   52
   53
   54
   55
   56
   57
   58
   59
   60
   61
   62
   63
   64
   65
   66
   67
   68
   69
   70
   71
   72
   73
   74
   75
   76
   77
   78
   79
   80
   81
   82
   83
   84
   85
   86
   87
   88
   89
   90
   91
   92
   93
   94
   95
   96
   97
   98
   99
  100
  101
  102
  103
  104
  105
  106
  107
  108
  109
  110
  111
  112
  113
  114
  115
  116
  117
  118
  119
  120
  121
  122
  123
  124
  125
  126
  127
  128
  129
  130
  131
  132
  133
  134
  135
  136
  137


media / filters / decrypting_audio_decoder.h [blame]

// Copyright 2012 The Chromium Authors
// 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 <memory>

#include "base/functional/callback.h"
#include "base/memory/raw_ptr.h"
#include "base/memory/scoped_refptr.h"
#include "base/memory/weak_ptr.h"
#include "media/base/audio_decoder.h"
#include "media/base/callback_registry.h"
#include "media/base/cdm_context.h"
#include "media/base/decryptor.h"
#include "media/base/demuxer_stream.h"

namespace base {
class SequencedTaskRunner;
}

namespace media {

class AudioTimestampHelper;
class DecoderBuffer;
class Decryptor;
class MediaLog;

// 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 |task_runner_| so
// that no locks are required for thread safety.
class MEDIA_EXPORT DecryptingAudioDecoder : public AudioDecoder {
 public:
  DecryptingAudioDecoder(
      const scoped_refptr<base::SequencedTaskRunner>& task_runner,
      MediaLog* media_log);

  DecryptingAudioDecoder(const DecryptingAudioDecoder&) = delete;
  DecryptingAudioDecoder& operator=(const DecryptingAudioDecoder&) = delete;

  ~DecryptingAudioDecoder() override;

  // Decoder implementation
  bool SupportsDecryption() const override;
  AudioDecoderType GetDecoderType() const override;

  // AudioDecoder implementation.
  void Initialize(const AudioDecoderConfig& config,
                  CdmContext* cdm_context,
                  InitCB init_cb,
                  const OutputCB& output_cb,
                  const WaitingCB& waiting_cb) override;
  void Decode(scoped_refptr<DecoderBuffer> buffer, DecodeCB decode_cb) override;
  void Reset(base::OnceClosure closure) override;

 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 State {
    kUninitialized = 0,
    kPendingDecoderInit,
    kIdle,
    kPendingDecode,
    kWaitingForKey,
    kDecodeFinished,
    kError
  };

  // Initializes the audio decoder on the |decryptor_| with |config_|.
  void InitializeDecoder();

  // Callback for Decryptor::InitializeAudioDecoder() during initialization.
  void FinishInitialization(bool success);

  void DecodePendingBuffer();

  // Callback for Decryptor::DecryptAndDecodeAudio().
  void DeliverFrame(int buffer_size,
                    Decryptor::Status status,
                    const Decryptor::AudioFrames& frames);

  // Callback for the CDM to notify |this|.
  void OnCdmContextEvent(CdmContext::Event event);

  // Resets decoder and calls |reset_cb_|.
  void DoReset();

  // Sets timestamps for |frames| and then passes them to |output_cb_|.
  void ProcessDecodedFrames(const Decryptor::AudioFrames& frames);

  // Set in constructor.
  scoped_refptr<base::SequencedTaskRunner> const task_runner_;
  const raw_ptr<MediaLog> media_log_;

  State state_ = kUninitialized;

  InitCB init_cb_;
  OutputCB output_cb_;
  DecodeCB decode_cb_;
  base::OnceClosure reset_cb_;
  WaitingCB waiting_cb_;

  // The current decoder configuration.
  AudioDecoderConfig config_;

  raw_ptr<Decryptor> decryptor_ = nullptr;

  // The buffer that needs decrypting/decoding.
  scoped_refptr<media::DecoderBuffer> pending_buffer_to_decode_;

  // Indicates the situation where new key is added during pending decode
  // (in other words, this variable can only be set in state kPendingDecode).
  // If this variable is true and kNoKey is returned then we need to try
  // decrypting/decoding again in case the newly added key is the correct
  // decryption key.
  bool key_added_while_decode_pending_ = false;

  std::unique_ptr<AudioTimestampHelper> timestamp_helper_;

  // Once Initialized() with encrypted content support, if the stream changes to
  // clear content, we want to ensure this decoder remains used.
  bool support_clear_content_ = false;

  // To keep the CdmContext event callback registered.
  std::unique_ptr<CallbackRegistration> event_cb_registration_;

  base::WeakPtrFactory<DecryptingAudioDecoder> weak_factory_{this};
};

}  // namespace media

#endif  // MEDIA_FILTERS_DECRYPTING_AUDIO_DECODER_H_