media/base/video_renderer.h

   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/buffering_state.h"
  12 #include "media/base/decryptor.h"
  13 #include "media/base/media_export.h"
  14 #include "media/base/pipeline_status.h"
  15 #include "media/base/time_source.h"
  16
  17 namespace media {
  18
  19 class DemuxerStream;
  20 class VideoDecoder;
  21 class VideoFrame;
  22
  23 class MEDIA_EXPORT VideoRenderer {
  24  public:
  25   // Used to paint VideoFrame.
  26   typedef base::Callback<void(const scoped_refptr<VideoFrame>&)> PaintCB;
  27
  28   VideoRenderer();
  29
  30   // Stops all operations and fires all pending callbacks.
  31   virtual ~VideoRenderer();
  32
  33   // Initializes a VideoRenderer with |stream|, executing |init_cb| upon
  34   // completion. If initialization fails, only |init_cb| (not |error_cb|) will
  35   // be called.
  36   //
  37   // |set_decryptor_ready_cb| is fired when a Decryptor is needed, i.e. when the
  38   // |stream| is encrypted.
  39   //
  40   // |statistics_cb| is executed periodically with video rendering stats, such
  41   // as dropped frames.
  42   //
  43   // |buffering_state_cb| is executed when video rendering has either run out of
  44   // data or has enough data to continue playback.
  45   //
  46   // |ended_cb| is executed when video rendering has reached the end of stream.
  47   //
  48   // |error_cb| is executed if an error was encountered after initialization.
  49   //
  50   // |wall_clock_time_cb| is used to convert media timestamps into wallclock
  51   // timestamps.
  52   //
  53   // |waiting_for_decryption_key_cb| is executed whenever the key needed to
  54   // decrypt the stream is not available.
  55   virtual void Initialize(
  56       DemuxerStream* stream,
  57       const PipelineStatusCB& init_cb,
  58       const SetDecryptorReadyCB& set_decryptor_ready_cb,
  59       const StatisticsCB& statistics_cb,
  60       const BufferingStateCB& buffering_state_cb,
  61       const base::Closure& ended_cb,
  62       const PipelineStatusCB& error_cb,
  63       const TimeSource::WallClockTimeCB& wall_clock_time_cb,
  64       const base::Closure& waiting_for_decryption_key_cb) = 0;
  65
  66   // Discards any video data and stops reading from |stream|, executing
  67   // |callback| when completed.
  68   //
  69   // Clients should expect |buffering_state_cb| to be called with
  70   // BUFFERING_HAVE_NOTHING while flushing is in progress.
  71   virtual void Flush(const base::Closure& callback) = 0;
  72
  73   // Starts playback at |timestamp| by reading from |stream| and decoding and
  74   // rendering video.
  75   //
  76   // Only valid to call after a successful Initialize() or Flush().
  77   virtual void StartPlayingFrom(base::TimeDelta timestamp) = 0;
  78
  79   // Called when time starts or stops moving. Time progresses when a base time
  80   // has been set and the playback rate is > 0. If either condition changes,
  81   // |time_progressing| will be false.
  82   virtual void OnTimeStateChanged(bool time_progressing) = 0;
  83
  84  private:
  85   DISALLOW_COPY_AND_ASSIGN(VideoRenderer);
  86 };
  87
  88 }  // namespace media
  89
  90 #endif  // MEDIA_BASE_VIDEO_RENDERER_H_