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
14namespace gfx {
15class Size;
16}
17
18namespace media {
19
20class DemuxerStream;
21class VideoDecoder;
22
23class MEDIA_EXPORT VideoRenderer {
24 public:
25  // Used to update the pipeline's clock time. The parameter is the time that
26  // the clock should not exceed.
27  typedef base::Callback<void(base::TimeDelta)> TimeCB;
28
29  // Executed when the natural size of the video has changed.
30  typedef base::Callback<void(const gfx::Size& size)> NaturalSizeChangedCB;
31
32  // Used to query the current time or duration of the media.
33  typedef base::Callback<base::TimeDelta()> TimeDeltaCB;
34
35  VideoRenderer();
36  virtual ~VideoRenderer();
37
38  // Initialize a VideoRenderer with |stream|, executing |init_cb| upon
39  // completion.
40  //
41  // |statistics_cb| is executed periodically with video rendering stats, such
42  // as dropped frames.
43  //
44  // |time_cb| is executed whenever time has advanced by way of video rendering.
45  //
46  // |size_changed_cb| is executed whenever the dimensions of the video has
47  // changed.
48  //
49  // |ended_cb| is executed when video rendering has reached the end of stream.
50  //
51  // |error_cb| is executed if an error was encountered.
52  //
53  // |get_time_cb| is used to query the current media playback time.
54  //
55  // |get_duration_cb| is used to query the media duration.
56  virtual void Initialize(DemuxerStream* stream,
57                          const PipelineStatusCB& init_cb,
58                          const StatisticsCB& statistics_cb,
59                          const TimeCB& time_cb,
60                          const NaturalSizeChangedCB& size_changed_cb,
61                          const base::Closure& ended_cb,
62                          const PipelineStatusCB& error_cb,
63                          const TimeDeltaCB& get_time_cb,
64                          const TimeDeltaCB& get_duration_cb) = 0;
65
66  // Start audio decoding and rendering at the current playback rate, executing
67  // |callback| when playback is underway.
68  virtual void Play(const base::Closure& callback) = 0;
69
70  // Temporarily suspend decoding and rendering video, executing |callback| when
71  // playback has been suspended.
72  virtual void Pause(const base::Closure& callback) = 0;
73
74  // Discard any video data, executing |callback| when completed.
75  virtual void Flush(const base::Closure& callback) = 0;
76
77  // Start prerolling video data for samples starting at |time|, executing
78  // |callback| when completed.
79  //
80  // Only valid to call after a successful Initialize() or Flush().
81  virtual void Preroll(base::TimeDelta time,
82                       const PipelineStatusCB& callback) = 0;
83
84  // Stop all operations in preparation for being deleted, executing |callback|
85  // when complete.
86  virtual void Stop(const base::Closure& callback) = 0;
87
88  // Updates the current playback rate.
89  virtual void SetPlaybackRate(float playback_rate) = 0;
90
91 private:
92  DISALLOW_COPY_AND_ASSIGN(VideoRenderer);
93};
94
95}  // namespace media
96
97#endif  // MEDIA_BASE_VIDEO_RENDERER_H_
98