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
  27 // DecoderSelector (creates if necessary and) initializes the proper
  28 // Decoder for a given DemuxerStream. If the given DemuxerStream is
  29 // encrypted, a DecryptingDemuxerStream may also be created.
  30 // The template parameter |StreamType| is the type of stream we will be
  31 // selecting a decoder for.
  32 template<DemuxerStream::Type StreamType>
  33 class MEDIA_EXPORT DecoderSelector {
  34  public:
  35   typedef DecoderStreamTraits<StreamType> StreamTraits;
  36   typedef typename StreamTraits::DecoderType Decoder;
  37
  38   // Indicates completion of Decoder selection.
  39   // - First parameter: The initialized Decoder. If it's set to NULL, then
  40   // Decoder initialization failed.
  41   // - Second parameter: The initialized DecryptingDemuxerStream. If it's not
  42   // NULL, then a DecryptingDemuxerStream is created and initialized to do
  43   // decryption for the initialized Decoder.
  44   // Note: The caller owns selected Decoder and DecryptingDemuxerStream.
  45   // The caller should call DecryptingDemuxerStream::Reset() before
  46   // calling Decoder::Reset() to release any pending decryption or read.
  47   typedef base::Callback<
  48       void(scoped_ptr<Decoder>,
  49            scoped_ptr<DecryptingDemuxerStream>)>
  50       SelectDecoderCB;
  51
  52   // |decoders| contains the Decoders to use when initializing.
  53   //
  54   // |set_decryptor_ready_cb| is optional. If |set_decryptor_ready_cb| is null,
  55   // no decryptor will be available to perform decryption.
  56   DecoderSelector(
  57       const scoped_refptr<base::SingleThreadTaskRunner>& message_loop,
  58       ScopedVector<Decoder> decoders,
  59       const SetDecryptorReadyCB& set_decryptor_ready_cb);
  60
  61   // Aborts pending Decoder selection and fires |select_decoder_cb| with
  62   // NULL and NULL immediately if it's pending.
  63   ~DecoderSelector();
  64
  65   // Initializes and selects a Decoder that can decode the |stream|.
  66   // Selected Decoder (and DecryptingDemuxerStream) is returned via
  67   // the |select_decoder_cb|.
  68   void SelectDecoder(DemuxerStream* stream,
  69                      bool low_delay,
  70                      const SelectDecoderCB& select_decoder_cb,
  71                      const typename Decoder::OutputCB& output_cb);
  72
  73  private:
  74   void DecryptingDecoderInitDone(PipelineStatus status);
  75   void DecryptingDemuxerStreamInitDone(PipelineStatus status);
  76   void InitializeDecoder();
  77   void DecoderInitDone(PipelineStatus status);
  78   void ReturnNullDecoder();
  79
  80   scoped_refptr<base::SingleThreadTaskRunner> task_runner_;
  81   ScopedVector<Decoder> decoders_;
  82   SetDecryptorReadyCB set_decryptor_ready_cb_;
  83
  84   DemuxerStream* input_stream_;
  85   bool low_delay_;
  86   SelectDecoderCB select_decoder_cb_;
  87   typename Decoder::OutputCB output_cb_;
  88
  89   scoped_ptr<Decoder> decoder_;
  90   scoped_ptr<DecryptingDemuxerStream> decrypted_stream_;
  91
  92   // NOTE: Weak pointers must be invalidated before all other member variables.
  93   base::WeakPtrFactory<DecoderSelector> weak_ptr_factory_;
  94
  95   DISALLOW_IMPLICIT_CONSTRUCTORS(DecoderSelector);
  96 };
  97
  98 typedef DecoderSelector<DemuxerStream::VIDEO> VideoDecoderSelector;
  99 typedef DecoderSelector<DemuxerStream::AUDIO> AudioDecoderSelector;
 100
 101 }  // namespace media
 102
 103 #endif  // MEDIA_FILTERS_DECODER_SELECTOR_H_