media/cast/sender/h264_vt_encoder.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_CAST_SENDER_H264_VT_ENCODER_H_
   6 #define MEDIA_CAST_SENDER_H264_VT_ENCODER_H_
   7
   8 #include "base/mac/scoped_cftyperef.h"
   9 #include "base/threading/thread_checker.h"
  10 #include "media/base/mac/videotoolbox_glue.h"
  11 #include "media/cast/sender/size_adaptable_video_encoder_base.h"
  12 #include "media/cast/sender/video_encoder.h"
  13
  14 namespace media {
  15 namespace cast {
  16
  17 // VideoToolbox implementation of the media::cast::VideoEncoder interface.
  18 // VideoToolbox makes no guarantees that it is thread safe, so this object is
  19 // pinned to the thread on which it is constructed. Supports changing frame
  20 // sizes directly.
  21 class H264VideoToolboxEncoder : public VideoEncoder {
  22   typedef CoreMediaGlue::CMSampleBufferRef CMSampleBufferRef;
  23   typedef VideoToolboxGlue::VTCompressionSessionRef VTCompressionSessionRef;
  24   typedef VideoToolboxGlue::VTEncodeInfoFlags VTEncodeInfoFlags;
  25
  26  public:
  27   // Returns true if the current platform and system configuration supports
  28   // using H264VideoToolboxEncoder with the given |video_config|.
  29   static bool IsSupported(const VideoSenderConfig& video_config);
  30
  31   H264VideoToolboxEncoder(
  32       const scoped_refptr<CastEnvironment>& cast_environment,
  33       const VideoSenderConfig& video_config,
  34       const StatusChangeCallback& status_change_cb);
  35   ~H264VideoToolboxEncoder() override;
  36
  37   // media::cast::VideoEncoder implementation
  38   bool EncodeVideoFrame(
  39       const scoped_refptr<media::VideoFrame>& video_frame,
  40       const base::TimeTicks& reference_time,
  41       const FrameEncodedCallback& frame_encoded_callback) override;
  42   void SetBitRate(int new_bit_rate) override;
  43   void GenerateKeyFrame() override;
  44   void LatestFrameIdToReference(uint32 frame_id) override;
  45   scoped_ptr<VideoFrameFactory> CreateVideoFrameFactory() override;
  46   void EmitFrames() override;
  47
  48  private:
  49   // VideoFrameFactory tied to the VideoToolbox encoder.
  50   class VideoFrameFactoryImpl;
  51
  52   // Reset the encoder's compression session by destroying the existing one
  53   // using DestroyCompressionSession() and creating a new one. The new session
  54   // is configured using ConfigureCompressionSession().
  55   void ResetCompressionSession();
  56
  57   // Configure the current compression session using current encoder settings.
  58   void ConfigureCompressionSession();
  59
  60   // Destroy the current compression session if any. Blocks until all pending
  61   // frames have been flushed out (similar to EmitFrames without doing any
  62   // encoding work).
  63   void DestroyCompressionSession();
  64
  65   // Update the encoder's target frame size by resetting the compression
  66   // session. This will also update the video frame factory.
  67   void UpdateFrameSize(const gfx::Size& size_needed);
  68
  69   // Set a compression session property.
  70   bool SetSessionProperty(CFStringRef key, int32_t value);
  71   bool SetSessionProperty(CFStringRef key, bool value);
  72   bool SetSessionProperty(CFStringRef key, CFStringRef value);
  73
  74   // Compression session callback function to handle compressed frames.
  75   static void CompressionCallback(void* encoder_opaque,
  76                                   void* request_opaque,
  77                                   OSStatus status,
  78                                   VTEncodeInfoFlags info,
  79                                   CMSampleBufferRef sbuf);
  80
  81   // The cast environment (contains worker threads & more).
  82   const scoped_refptr<CastEnvironment> cast_environment_;
  83
  84   // VideoToolboxGlue provides access to VideoToolbox at runtime.
  85   const VideoToolboxGlue* const videotoolbox_glue_;
  86
  87   // VideoSenderConfig copy so we can create compression sessions on demand.
  88   // This is needed to recover from backgrounding and other events that can
  89   // invalidate compression sessions.
  90   const VideoSenderConfig video_config_;
  91
  92   // Frame size of the current compression session. Can be changed by submitting
  93   // a frame of a different size, which will cause a compression session reset.
  94   gfx::Size frame_size_;
  95
  96   // Callback used to report initialization status and runtime errors.
  97   const StatusChangeCallback status_change_cb_;
  98
  99   // Thread checker to enforce that this object is used on a specific thread.
 100   base::ThreadChecker thread_checker_;
 101
 102   // The compression session.
 103   base::ScopedCFTypeRef<VTCompressionSessionRef> compression_session_;
 104
 105   // Video frame factory tied to the encoder.
 106   scoped_refptr<VideoFrameFactoryImpl> video_frame_factory_;
 107
 108   // The ID of the last frame that was emitted.
 109   uint32 last_frame_id_;
 110
 111   // Force next frame to be a keyframe.
 112   bool encode_next_frame_as_keyframe_;
 113
 114   // NOTE: Weak pointers must be invalidated before all other member variables.
 115   base::WeakPtrFactory<H264VideoToolboxEncoder> weak_factory_;
 116
 117   DISALLOW_COPY_AND_ASSIGN(H264VideoToolboxEncoder);
 118 };
 119
 120 }  // namespace cast
 121 }  // namespace media
 122
 123 #endif  // MEDIA_CAST_SENDER_H264_VT_ENCODER_H_