media/base/demuxer_stream.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_BASE_DEMUXER_STREAM_H_
   6 #define MEDIA_BASE_DEMUXER_STREAM_H_
   7
   8 #include "base/callback.h"
   9 #include "base/memory/ref_counted.h"
  10 #include "media/base/media_export.h"
  11
  12 namespace media {
  13
  14 class AudioDecoderConfig;
  15 class DecoderBuffer;
  16 class VideoDecoderConfig;
  17
  18 class MEDIA_EXPORT DemuxerStream {
  19  public:
  20   enum Type {
  21     UNKNOWN,
  22     AUDIO,
  23     VIDEO,
  24     TEXT,
  25     NUM_TYPES,  // Always keep this entry as the last one!
  26   };
  27
  28   // Status returned in the Read() callback.
  29   //  kOk : Indicates the second parameter is Non-NULL and contains media data
  30   //        or the end of the stream.
  31   //  kAborted : Indicates an aborted Read(). This can happen if the
  32   //             DemuxerStream gets flushed and doesn't have any more data to
  33   //             return. The second parameter MUST be NULL when this status is
  34   //             returned.
  35   //  kConfigChange : Indicates that the AudioDecoderConfig or
  36   //                  VideoDecoderConfig for the stream has changed.
  37   //                  The DemuxerStream expects an audio_decoder_config() or
  38   //                  video_decoder_config() call before Read() will start
  39   //                  returning DecoderBuffers again. The decoder will need this
  40   //                  new configuration to properly decode the buffers read
  41   //                  from this point forward. The second parameter MUST be NULL
  42   //                  when this status is returned.
  43   //                  This will only be returned if SupportsConfigChanges()
  44   //                  returns 'true' for this DemuxerStream.
  45   enum Status {
  46     kOk,
  47     kAborted,
  48     kConfigChanged,
  49   };
  50
  51   // Request a buffer to returned via the provided callback.
  52   //
  53   // The first parameter indicates the status of the read.
  54   // The second parameter is non-NULL and contains media data
  55   // or the end of the stream if the first parameter is kOk. NULL otherwise.
  56   typedef base::Callback<void(Status,
  57                               const scoped_refptr<DecoderBuffer>&)>ReadCB;
  58   virtual void Read(const ReadCB& read_cb) = 0;
  59
  60   // Returns the audio decoder configuration. It is an error to call this method
  61   // if type() != AUDIO.
  62   virtual AudioDecoderConfig audio_decoder_config() = 0;
  63
  64   // Returns the video decoder configuration. It is an error to call this method
  65   // if type() != VIDEO.
  66   virtual VideoDecoderConfig video_decoder_config() = 0;
  67
  68   // Returns the type of stream.
  69   virtual Type type() = 0;
  70
  71   virtual void EnableBitstreamConverter() = 0;
  72
  73   // Whether or not this DemuxerStream allows midstream configuration changes.
  74   //
  75   // A DemuxerStream that returns 'true' to this may return the 'kConfigChange'
  76   // status from a Read() call. In this case the client is expected to be
  77   // capable of taking appropriate action to handle config changes. Otherwise
  78   // audio_decoder_config() and video_decoder_config()'s return values are
  79   // guaranteed to remain constant, and the client may make optimizations based
  80   // on this.
  81   virtual bool SupportsConfigChanges() = 0;
  82
  83  protected:
  84   // Only allow concrete implementations to get deleted.
  85   virtual ~DemuxerStream();
  86 };
  87
  88 }  // namespace media
  89
  90 #endif  // MEDIA_BASE_DEMUXER_STREAM_H_