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   Renderer();
  24
  25   // Stops rendering and fires any pending callbacks.
  26   virtual ~Renderer();
  27
  28   // Initializes the Renderer with |demuxer_stream_provider|, executing
  29   // |init_cb| upon completion.  If initialization fails, only |init_cb| (not
  30   // |error_cb|) should be called.  |demuxer_stream_provider| must be valid for
  31   // the lifetime of the Renderer object.  |init_cb| must only be run after this
  32   // method has returned.  Firing |init_cb| may result in the immediate
  33   // destruction of the caller, so it must be run only prior to returning.
  34   //
  35   // Permanent callbacks:
  36   // - |statistics_cb|: Executed periodically with rendering statistics.
  37   // - |buffering_state_cb|: Executed when buffering state is changed.
  38   // - |ended_cb|: Executed when rendering has reached the end of stream.
  39   // - |error_cb|: Executed if any error was encountered after initialization.
  40   // - |waiting_for_decryption_key_cb|: Executed whenever the key needed to
  41   //                                    decrypt the stream is not available.
  42   virtual void Initialize(
  43       DemuxerStreamProvider* demuxer_stream_provider,
  44       const PipelineStatusCB& init_cb,
  45       const StatisticsCB& statistics_cb,
  46       const BufferingStateCB& buffering_state_cb,
  47       const base::Closure& ended_cb,
  48       const PipelineStatusCB& error_cb,
  49       const base::Closure& waiting_for_decryption_key_cb) = 0;
  50
  51   // Associates the |cdm_context| with this Renderer for decryption (and
  52   // decoding) of media data, then fires |cdm_attached_cb| with the result.
  53   virtual void SetCdm(CdmContext* cdm_context,
  54                       const CdmAttachedCB& cdm_attached_cb) = 0;
  55
  56   // The following functions must be called after Initialize().
  57
  58   // Discards any buffered data, executing |flush_cb| when completed.
  59   virtual void Flush(const base::Closure& flush_cb) = 0;
  60
  61   // Starts rendering from |time|.
  62   virtual void StartPlayingFrom(base::TimeDelta time) = 0;
  63
  64   // Updates the current playback rate. The default playback rate should be 1.
  65   virtual void SetPlaybackRate(double playback_rate) = 0;
  66
  67   // Sets the output volume. The default volume should be 1.
  68   virtual void SetVolume(float volume) = 0;
  69
  70   // Returns the current media time.
  71   virtual base::TimeDelta GetMediaTime() = 0;
  72
  73   // Returns whether |this| renders audio.
  74   virtual bool HasAudio() = 0;
  75
  76   // Returns whether |this| renders video.
  77   virtual bool HasVideo() = 0;
  78
  79  private:
  80   DISALLOW_COPY_AND_ASSIGN(Renderer);
  81 };
  82
  83 }  // namespace media
  84
  85 #endif  // MEDIA_BASE_RENDERER_H_