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 #include "media/base/video_rotation.h"
  12
  13 namespace media {
  14
  15 class AudioDecoderConfig;
  16 class DecoderBuffer;
  17 class VideoDecoderConfig;
  18
  19 class MEDIA_EXPORT DemuxerStream {
  20  public:
  21   enum Type {
  22     UNKNOWN,
  23     AUDIO,
  24     VIDEO,
  25     TEXT,
  26     NUM_TYPES,  // Always keep this entry as the last one!
  27   };
  28
  29   // Status returned in the Read() callback.
  30   //  kOk : Indicates the second parameter is Non-NULL and contains media data
  31   //        or the end of the stream.
  32   //  kAborted : Indicates an aborted Read(). This can happen if the
  33   //             DemuxerStream gets flushed and doesn't have any more data to
  34   //             return. The second parameter MUST be NULL when this status is
  35   //             returned.
  36   //  kConfigChange : Indicates that the AudioDecoderConfig or
  37   //                  VideoDecoderConfig for the stream has changed.
  38   //                  The DemuxerStream expects an audio_decoder_config() or
  39   //                  video_decoder_config() call before Read() will start
  40   //                  returning DecoderBuffers again. The decoder will need this
  41   //                  new configuration to properly decode the buffers read
  42   //                  from this point forward. The second parameter MUST be NULL
  43   //                  when this status is returned.
  44   //                  This will only be returned if SupportsConfigChanges()
  45   //                  returns 'true' for this DemuxerStream.
  46   enum Status {
  47     kOk,
  48     kAborted,
  49     kConfigChanged,
  50   };
  51
  52   // Request a buffer to returned via the provided callback.
  53   //
  54   // The first parameter indicates the status of the read.
  55   // The second parameter is non-NULL and contains media data
  56   // or the end of the stream if the first parameter is kOk. NULL otherwise.
  57   typedef base::Callback<void(Status,
  58                               const scoped_refptr<DecoderBuffer>&)>ReadCB;
  59   virtual void Read(const ReadCB& read_cb) = 0;
  60
  61   // Returns the audio decoder configuration. It is an error to call this method
  62   // if type() != AUDIO.
  63   virtual AudioDecoderConfig audio_decoder_config() = 0;
  64
  65   // Returns the video decoder configuration. It is an error to call this method
  66   // if type() != VIDEO.
  67   virtual VideoDecoderConfig video_decoder_config() = 0;
  68
  69   // Returns the type of stream.
  70   virtual Type type() = 0;
  71
  72   virtual void EnableBitstreamConverter() = 0;
  73
  74   // Whether or not this DemuxerStream allows midstream configuration changes.
  75   //
  76   // A DemuxerStream that returns 'true' to this may return the 'kConfigChange'
  77   // status from a Read() call. In this case the client is expected to be
  78   // capable of taking appropriate action to handle config changes. Otherwise
  79   // audio_decoder_config() and video_decoder_config()'s return values are
  80   // guaranteed to remain constant, and the client may make optimizations based
  81   // on this.
  82   virtual bool SupportsConfigChanges() = 0;
  83
  84   virtual VideoRotation video_rotation() = 0;
  85
  86  protected:
  87   // Only allow concrete implementations to get deleted.
  88   virtual ~DemuxerStream();
  89 };
  90
  91 }  // namespace media
  92
  93 #endif  // MEDIA_BASE_DEMUXER_STREAM_H_