media/base/renderer.h

   1 // Copyright 2014 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_RENDERER_H_
   6 #define MEDIA_BASE_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 DemuxerStreamProvider;
  18 class MediaKeys;
  19 class VideoFrame;
  20
  21 class MEDIA_EXPORT Renderer {
  22  public:
  23   typedef base::Callback<void(const scoped_refptr<VideoFrame>&)> PaintCB;
  24   typedef base::Callback<base::TimeDelta()> TimeDeltaCB;
  25
  26   Renderer();
  27
  28   // Stops rendering and fires any pending callbacks.
  29   virtual ~Renderer();
  30
  31   // Initializes the Renderer with |demuxer_stream_provider|, executing
  32   // |init_cb| upon completion.  If initialization failed, fires |error_cb|
  33   // before |init_cb|. |demuxer_stream_provider| must be valid throughout the
  34   // lifetime of the Renderer object.
  35   //
  36   // Permanent callbacks:
  37   // - |statistics_cb|: Executed periodically with rendering statistics.
  38   // - |buffering_state_cb|: Executed when buffering state is changed.
  39   // - |paint_cb|: Executed when there is a VideoFrame ready to paint.  Can be
  40   //               ignored if the Renderer handles the painting by itself. Can
  41   //               be called from any thread.
  42   // - |ended_cb|: Executed when rendering has reached the end of stream.
  43   // - |error_cb|: Executed if any error was encountered during rendering.
  44   virtual void Initialize(DemuxerStreamProvider* demuxer_stream_provider,
  45                           const base::Closure& init_cb,
  46                           const StatisticsCB& statistics_cb,
  47                           const BufferingStateCB& buffering_state_cb,
  48                           const PaintCB& paint_cb,
  49                           const base::Closure& ended_cb,
  50                           const PipelineStatusCB& error_cb) = 0;
  51
  52   // The following functions must be called after Initialize().
  53
  54   // Discards any buffered data, executing |flush_cb| when completed.
  55   virtual void Flush(const base::Closure& flush_cb) = 0;
  56
  57   // Starts rendering from |time|.
  58   virtual void StartPlayingFrom(base::TimeDelta time) = 0;
  59
  60   // Updates the current playback rate. The default playback rate should be 1.
  61   virtual void SetPlaybackRate(float playback_rate) = 0;
  62
  63   // Sets the output volume. The default volume should be 1.
  64   virtual void SetVolume(float volume) = 0;
  65
  66   // Returns the current media time.
  67   virtual base::TimeDelta GetMediaTime() = 0;
  68
  69   // Returns whether |this| renders audio.
  70   virtual bool HasAudio() = 0;
  71
  72   // Returns whether |this| renders video.
  73   virtual bool HasVideo() = 0;
  74
  75   // Associates the |cdm| with this Renderer.
  76   virtual void SetCdm(MediaKeys* cdm) = 0;
  77
  78  private:
  79   DISALLOW_COPY_AND_ASSIGN(Renderer);
  80 };
  81
  82 }  // namespace media
  83
  84 #endif  // MEDIA_BASE_RENDERER_H_