media/filters/decoder_selector.h

   1 // Copyright 2014 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_DECODER_SELECTOR_H_
   6 #define MEDIA_FILTERS_DECODER_SELECTOR_H_
   7
   8 #include "base/callback.h"
   9 #include "base/memory/ref_counted.h"
  10 #include "base/memory/scoped_vector.h"
  11 #include "base/memory/weak_ptr.h"
  12 #include "media/base/decryptor.h"
  13 #include "media/base/demuxer_stream.h"
  14 #include "media/base/pipeline_status.h"
  15 #include "media/filters/decoder_stream_traits.h"
  16
  17 namespace base {
  18 class SingleThreadTaskRunner;
  19 }
  20
  21 namespace media {
  22
  23 class DecoderBuffer;
  24 class DecryptingDemuxerStream;
  25 class Decryptor;
  26 class MediaLog;
  27
  28 // DecoderSelector (creates if necessary and) initializes the proper
  29 // Decoder for a given DemuxerStream. If the given DemuxerStream is
  30 // encrypted, a DecryptingDemuxerStream may also be created.
  31 // The template parameter |StreamType| is the type of stream we will be
  32 // selecting a decoder for.
  33 template<DemuxerStream::Type StreamType>
  34 class MEDIA_EXPORT DecoderSelector {
  35  public:
  36   typedef DecoderStreamTraits<StreamType> StreamTraits;
  37   typedef typename StreamTraits::DecoderType Decoder;
  38
  39   // Indicates completion of Decoder selection.
  40   // - First parameter: The initialized Decoder. If it's set to NULL, then
  41   // Decoder initialization failed.
  42   // - Second parameter: The initialized DecryptingDemuxerStream. If it's not
  43   // NULL, then a DecryptingDemuxerStream is created and initialized to do
  44   // decryption for the initialized Decoder.
  45   // Note: The caller owns selected Decoder and DecryptingDemuxerStream.
  46   // The caller should call DecryptingDemuxerStream::Reset() before
  47   // calling Decoder::Reset() to release any pending decryption or read.
  48   typedef base::Callback<
  49       void(scoped_ptr<Decoder>,
  50            scoped_ptr<DecryptingDemuxerStream>)>
  51       SelectDecoderCB;
  52
  53   // |decoders| contains the Decoders to use when initializing.
  54   DecoderSelector(
  55       const scoped_refptr<base::SingleThreadTaskRunner>& message_loop,
  56       ScopedVector<Decoder> decoders,
  57       const scoped_refptr<MediaLog>& media_log);
  58
  59   // Aborts pending Decoder selection and fires |select_decoder_cb| with
  60   // NULL and NULL immediately if it's pending.
  61   ~DecoderSelector();
  62
  63   // Initializes and selects the first Decoder that can decode the |stream|.
  64   // The selected Decoder (and DecryptingDemuxerStream) is returned via
  65   // the |select_decoder_cb|.
  66   // Notes:
  67   // 1. This must not be called again before |select_decoder_cb| is run.
  68   // 2. Decoders that fail to initialize will be deleted. Future calls will
  69   //    select from the decoders following the decoder that was last returned.
  70   // 3. |set_decryptor_ready_cb| is optional. If |set_decryptor_ready_cb| is
  71   //    null, no decryptor will be available to perform decryption.
  72   void SelectDecoder(DemuxerStream* stream,
  73                      const SetDecryptorReadyCB& set_decryptor_ready_cb,
  74                      const SelectDecoderCB& select_decoder_cb,
  75                      const typename Decoder::OutputCB& output_cb,
  76                      const base::Closure& waiting_for_decryption_key_cb);
  77
  78  private:
  79   void DecryptingDecoderInitDone(bool success);
  80   void DecryptingDemuxerStreamInitDone(PipelineStatus status);
  81   void InitializeDecoder();
  82   void DecoderInitDone(bool success);
  83   void ReturnNullDecoder();
  84
  85   scoped_refptr<base::SingleThreadTaskRunner> task_runner_;
  86   ScopedVector<Decoder> decoders_;
  87   scoped_refptr<MediaLog> media_log_;
  88
  89   DemuxerStream* input_stream_;
  90   SetDecryptorReadyCB set_decryptor_ready_cb_;
  91   SelectDecoderCB select_decoder_cb_;
  92   typename Decoder::OutputCB output_cb_;
  93   base::Closure waiting_for_decryption_key_cb_;
  94
  95   scoped_ptr<Decoder> decoder_;
  96   scoped_ptr<DecryptingDemuxerStream> decrypted_stream_;
  97
  98   // NOTE: Weak pointers must be invalidated before all other member variables.
  99   base::WeakPtrFactory<DecoderSelector> weak_ptr_factory_;
 100
 101   DISALLOW_IMPLICIT_CONSTRUCTORS(DecoderSelector);
 102 };
 103
 104 typedef DecoderSelector<DemuxerStream::VIDEO> VideoDecoderSelector;
 105 typedef DecoderSelector<DemuxerStream::AUDIO> AudioDecoderSelector;
 106
 107 }  // namespace media
 108
 109 #endif  // MEDIA_FILTERS_DECODER_SELECTOR_H_