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/cdm_context.h"
  13 #include "media/base/media_export.h"
  14 #include "media/base/pipeline_status.h"
  15
  16 namespace media {
  17
  18 class DemuxerStreamProvider;
  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 fails, only |init_cb| (not
  33   // |error_cb|) should be called.  |demuxer_stream_provider| must be valid for
  34   // the lifetime of the Renderer object.  |init_cb| must only be run after this
  35   // method has returned.  Firing |init_cb| may result in the immediate
  36   // destruction of the caller, so it must be run only prior to returning.
  37   //
  38   // Permanent callbacks:
  39   // - |statistics_cb|: Executed periodically with rendering statistics.
  40   // - |buffering_state_cb|: Executed when buffering state is changed.
  41   // - |paint_cb|: Executed when there is a VideoFrame ready to paint.  Can be
  42   //               ignored if the Renderer handles the painting by itself. Can
  43   //               be called from any thread.
  44   // - |ended_cb|: Executed when rendering has reached the end of stream.
  45   // - |error_cb|: Executed if any error was encountered after initialization.
  46   // - |waiting_for_decryption_key_cb|: Executed whenever the key needed to
  47   //                                    decrypt the stream is not available.
  48   virtual void Initialize(
  49       DemuxerStreamProvider* demuxer_stream_provider,
  50       const PipelineStatusCB& init_cb,
  51       const StatisticsCB& statistics_cb,
  52       const BufferingStateCB& buffering_state_cb,
  53       const PaintCB& paint_cb,
  54       const base::Closure& ended_cb,
  55       const PipelineStatusCB& error_cb,
  56       const base::Closure& waiting_for_decryption_key_cb) = 0;
  57
  58   // Associates the |cdm_context| with this Renderer for decryption (and
  59   // decoding) of media data, then fires |cdm_attached_cb| with the result.
  60   virtual void SetCdm(CdmContext* cdm_context,
  61                       const CdmAttachedCB& cdm_attached_cb) = 0;
  62
  63   // The following functions must be called after Initialize().
  64
  65   // Discards any buffered data, executing |flush_cb| when completed.
  66   virtual void Flush(const base::Closure& flush_cb) = 0;
  67
  68   // Starts rendering from |time|.
  69   virtual void StartPlayingFrom(base::TimeDelta time) = 0;
  70
  71   // Updates the current playback rate. The default playback rate should be 1.
  72   virtual void SetPlaybackRate(float playback_rate) = 0;
  73
  74   // Sets the output volume. The default volume should be 1.
  75   virtual void SetVolume(float volume) = 0;
  76
  77   // Returns the current media time.
  78   virtual base::TimeDelta GetMediaTime() = 0;
  79
  80   // Returns whether |this| renders audio.
  81   virtual bool HasAudio() = 0;
  82
  83   // Returns whether |this| renders video.
  84   virtual bool HasVideo() = 0;
  85
  86  private:
  87   DISALLOW_COPY_AND_ASSIGN(Renderer);
  88 };
  89
  90 }  // namespace media
  91
  92 #endif  // MEDIA_BASE_RENDERER_H_