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/media_export.h" 12 #include "media/base/pipeline_status.h" 13 14 namespace media { 15 16 class DemuxerStream; 17 class VideoDecoder; 18 19 class MEDIA_EXPORT VideoRenderer { 20 public: 21 // Used to update the pipeline's clock time. The parameter is the time that 22 // the clock should not exceed. 23 typedef base::Callback<void(base::TimeDelta)> TimeCB; 24 25 // Used to query the current time or duration of the media. 26 typedef base::Callback<base::TimeDelta()> TimeDeltaCB; 27 28 VideoRenderer(); 29 virtual ~VideoRenderer(); 30 31 // Initialize a VideoRenderer with |stream|, executing |init_cb| upon 32 // completion. 33 // 34 // |statistics_cb| is executed periodically with video rendering stats, such 35 // as dropped frames. 36 // 37 // |time_cb| is executed whenever time has advanced by way of video rendering. 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 // 45 // |get_duration_cb| is used to query the media duration. 46 virtual void Initialize(DemuxerStream* stream, 47 bool low_delay, 48 const PipelineStatusCB& init_cb, 49 const StatisticsCB& statistics_cb, 50 const TimeCB& time_cb, 51 const base::Closure& ended_cb, 52 const PipelineStatusCB& error_cb, 53 const TimeDeltaCB& get_time_cb, 54 const TimeDeltaCB& get_duration_cb) = 0; 55 56 // Start audio decoding and rendering at the current playback rate, executing 57 // |callback| when playback is underway. 58 virtual void Play(const base::Closure& callback) = 0; 59 60 // Discard any video data and stop reading from |stream|, executing |callback| 61 // when completed. 62 virtual void Flush(const base::Closure& callback) = 0; 63 64 // Start prerolling video data. If |time| equals kNoTimestamp() then all 65 // samples delivered to the renderer are used to complete preroll. If |time| 66 // does not equal kNoTimestamp(), then any samples delivered to the renderer 67 // with timestamps less than |time| are silently dropped and not used to 68 // satisfy preroll. |callback| is executed when preroll has completed. 69 // 70 // Only valid to call after a successful Initialize(), Pause(), or Flush(). 71 virtual void Preroll(base::TimeDelta time, 72 const PipelineStatusCB& callback) = 0; 73 74 // Stop all operations in preparation for being deleted, executing |callback| 75 // when complete. 76 virtual void Stop(const base::Closure& callback) = 0; 77 78 // Updates the current playback rate. 79 virtual void SetPlaybackRate(float playback_rate) = 0; 80 81 private: 82 DISALLOW_COPY_AND_ASSIGN(VideoRenderer); 83 }; 84 85 } // namespace media 86 87 #endif // MEDIA_BASE_VIDEO_RENDERER_H_ 88