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   enum Liveness {
  30     LIVENESS_UNKNOWN,
  31     LIVENESS_RECORDED,
  32     LIVENESS_LIVE,
  33   };
  34
  35   // Status returned in the Read() callback.
  36   //  kOk : Indicates the second parameter is Non-NULL and contains media data
  37   //        or the end of the stream.
  38   //  kAborted : Indicates an aborted Read(). This can happen if the
  39   //             DemuxerStream gets flushed and doesn't have any more data to
  40   //             return. The second parameter MUST be NULL when this status is
  41   //             returned.
  42   //  kConfigChange : Indicates that the AudioDecoderConfig or
  43   //                  VideoDecoderConfig for the stream has changed.
  44   //                  The DemuxerStream expects an audio_decoder_config() or
  45   //                  video_decoder_config() call before Read() will start
  46   //                  returning DecoderBuffers again. The decoder will need this
  47   //                  new configuration to properly decode the buffers read
  48   //                  from this point forward. The second parameter MUST be NULL
  49   //                  when this status is returned.
  50   //                  This will only be returned if SupportsConfigChanges()
  51   //                  returns 'true' for this DemuxerStream.
  52   enum Status {
  53     kOk,
  54     kAborted,
  55     kConfigChanged,
  56   };
  57
  58   // Request a buffer to returned via the provided callback.
  59   //
  60   // The first parameter indicates the status of the read.
  61   // The second parameter is non-NULL and contains media data
  62   // or the end of the stream if the first parameter is kOk. NULL otherwise.
  63   typedef base::Callback<void(Status,
  64                               const scoped_refptr<DecoderBuffer>&)>ReadCB;
  65   virtual void Read(const ReadCB& read_cb) = 0;
  66
  67   // Returns the audio/video decoder configuration. It is an error to call the
  68   // audio method on a video stream and vice versa. After |kConfigChanged| is
  69   // returned in a Read(), the caller should call this method again to retrieve
  70   // the new config.
  71   virtual AudioDecoderConfig audio_decoder_config() = 0;
  72   virtual VideoDecoderConfig video_decoder_config() = 0;
  73
  74   // Returns the type of stream.
  75   virtual Type type() const = 0;
  76
  77   // Returns liveness of the streams provided, i.e. whether recorded or live.
  78   virtual Liveness liveness() const;
  79
  80   virtual void EnableBitstreamConverter();
  81
  82   // Whether or not this DemuxerStream allows midstream configuration changes.
  83   //
  84   // A DemuxerStream that returns 'true' to this may return the 'kConfigChange'
  85   // status from a Read() call. In this case the client is expected to be
  86   // capable of taking appropriate action to handle config changes. Otherwise
  87   // audio_decoder_config() and video_decoder_config()'s return values are
  88   // guaranteed to remain constant, and the client may make optimizations based
  89   // on this.
  90   virtual bool SupportsConfigChanges() = 0;
  91
  92   virtual VideoRotation video_rotation() = 0;
  93
  94  protected:
  95   // Only allow concrete implementations to get deleted.
  96   virtual ~DemuxerStream();
  97 };
  98
  99 }  // namespace media
 100
 101 #endif  // MEDIA_BASE_DEMUXER_STREAM_H_