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/media_export.h" 13 #include "media/base/pipeline_status.h" 14 15 namespace media { 16 17 class DemuxerStream; 18 class VideoDecoder; 19 20 class MEDIA_EXPORT VideoRenderer { 21 public: 22 // Used to query the current time or duration of the media. 23 typedef base::Callback<base::TimeDelta()> TimeDeltaCB; 24 25 VideoRenderer(); 26 27 // Stops all operations and fires all pending callbacks. 28 virtual ~VideoRenderer(); 29 30 // Initializes a VideoRenderer with |stream|, executing |init_cb| upon 31 // completion. 32 // 33 // |statistics_cb| is executed periodically with video rendering stats, such 34 // as dropped frames. 35 // 36 // |buffering_state_cb| is executed when video rendering has either run out of 37 // data or has enough data to continue playback. 38 // 39 // |ended_cb| is executed when video rendering has reached the end of stream. 40 // 41 // |error_cb| is executed if an error was encountered. 42 // 43 // |get_time_cb| is used to query the current media playback time. 44 virtual void Initialize(DemuxerStream* stream, 45 bool low_delay, 46 const PipelineStatusCB& init_cb, 47 const StatisticsCB& statistics_cb, 48 const BufferingStateCB& buffering_state_cb, 49 const base::Closure& ended_cb, 50 const PipelineStatusCB& error_cb, 51 const TimeDeltaCB& get_time_cb) = 0; 52 53 // Discards any video data and stops reading from |stream|, executing 54 // |callback| when completed. 55 // 56 // Clients should expect |buffering_state_cb| to be called with 57 // BUFFERING_HAVE_NOTHING while flushing is in progress. 58 virtual void Flush(const base::Closure& callback) = 0; 59 60 // Starts playback at |timestamp| by reading from |stream| and decoding and 61 // rendering video. 62 // 63 // Only valid to call after a successful Initialize() or Flush(). 64 virtual void StartPlayingFrom(base::TimeDelta timestamp) = 0; 65 66 private: 67 DISALLOW_COPY_AND_ASSIGN(VideoRenderer); 68 }; 69 70 } // namespace media 71 72 #endif // MEDIA_BASE_VIDEO_RENDERER_H_ 73