media/base/video_renderer.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_VIDEO_RENDERER_H_
   6 #define MEDIA_BASE_VIDEO_RENDERER_H_
   7
   8 #include "base/callback.h"
   9 #include "base/memory/ref_counted.h"
  10 #include "base/time/time.h"
  11 #include "media/base/buffering_state.h"
  12 #include "media/base/decryptor.h"
  13 #include "media/base/media_export.h"
  14 #include "media/base/pipeline_status.h"
  15
  16 namespace media {
  17
  18 class DemuxerStream;
  19 class VideoDecoder;
  20 class VideoFrame;
  21
  22 class MEDIA_EXPORT VideoRenderer {
  23  public:
  24   // Used to paint VideoFrame.
  25   typedef base::Callback<void(const scoped_refptr<VideoFrame>&)> PaintCB;
  26
  27   // Used to query the current time or duration of the media.
  28   typedef base::Callback<base::TimeDelta()> TimeDeltaCB;
  29
  30   VideoRenderer();
  31
  32   // Stops all operations and fires all pending callbacks.
  33   virtual ~VideoRenderer();
  34
  35   // Initializes a VideoRenderer with |stream|, executing |init_cb| upon
  36   // completion.
  37   //
  38   // |set_decryptor_ready_cb| is fired when a Decryptor is needed, i.e. when the
  39   // |stream| is encrypted.
  40   //
  41   // |statistics_cb| is executed periodically with video rendering stats, such
  42   // as dropped frames.
  43   //
  44   // |buffering_state_cb| is executed when video rendering has either run out of
  45   // data or has enough data to continue playback.
  46   //
  47   // |paint_cb| is executed on the video frame timing thread whenever a new
  48   // frame is available for painting. Can be called from any thread.
  49   //
  50   // |ended_cb| is executed when video rendering has reached the end of stream.
  51   //
  52   // |error_cb| is executed if an error was encountered.
  53   //
  54   // |get_time_cb| is used to query the current media playback time.
  55   virtual void Initialize(DemuxerStream* stream,
  56                           const PipelineStatusCB& init_cb,
  57                           const SetDecryptorReadyCB& set_decryptor_ready_cb,
  58                           const StatisticsCB& statistics_cb,
  59                           const BufferingStateCB& buffering_state_cb,
  60                           const PaintCB& paint_cb,
  61                           const base::Closure& ended_cb,
  62                           const PipelineStatusCB& error_cb,
  63                           const TimeDeltaCB& get_time_cb) = 0;
  64
  65   // Discards any video data and stops reading from |stream|, executing
  66   // |callback| when completed.
  67   //
  68   // Clients should expect |buffering_state_cb| to be called with
  69   // BUFFERING_HAVE_NOTHING while flushing is in progress.
  70   virtual void Flush(const base::Closure& callback) = 0;
  71
  72   // Starts playback at |timestamp| by reading from |stream| and decoding and
  73   // rendering video.
  74   //
  75   // Only valid to call after a successful Initialize() or Flush().
  76   virtual void StartPlayingFrom(base::TimeDelta timestamp) = 0;
  77
  78  private:
  79   DISALLOW_COPY_AND_ASSIGN(VideoRenderer);
  80 };
  81
  82 }  // namespace media
  83
  84 #endif  // MEDIA_BASE_VIDEO_RENDERER_H_