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      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_CODECS_VP8_VP8_ENCODER_H_
      6 #define MEDIA_CAST_SENDER_CODECS_VP8_VP8_ENCODER_H_
      7 
      8 #include "base/basictypes.h"
      9 #include "base/memory/scoped_ptr.h"
     10 #include "base/threading/thread_checker.h"
     11 #include "base/time/time.h"
     12 #include "media/cast/cast_config.h"
     13 #include "media/cast/sender/software_video_encoder.h"
     14 #include "third_party/libvpx/source/libvpx/vpx/vpx_encoder.h"
     15 
     16 namespace media {
     17 class VideoFrame;
     18 }
     19 
     20 // VPX forward declaration.
     21 typedef struct vpx_codec_ctx vpx_enc_ctx_t;
     22 
     23 namespace media {
     24 namespace cast {
     25 
     26 const int kNumberOfVp8VideoBuffers = 3;
     27 
     28 class Vp8Encoder : public SoftwareVideoEncoder {
     29  public:
     30   Vp8Encoder(const VideoSenderConfig& video_config, int max_unacked_frames);
     31 
     32   virtual ~Vp8Encoder();
     33 
     34   // Initialize the encoder before Encode() can be called. This method
     35   // must be called on the thread that Encode() is called.
     36   virtual void Initialize() OVERRIDE;
     37 
     38   // Encode a raw image (as a part of a video stream).
     39   virtual bool Encode(const scoped_refptr<media::VideoFrame>& video_frame,
     40                       EncodedFrame* encoded_image) OVERRIDE;
     41 
     42   // Update the encoder with a new target bit rate.
     43   virtual void UpdateRates(uint32 new_bitrate) OVERRIDE;
     44 
     45   // Set the next frame to be a key frame.
     46   virtual void GenerateKeyFrame() OVERRIDE;
     47 
     48   virtual void LatestFrameIdToReference(uint32 frame_id) OVERRIDE;
     49 
     50  private:
     51   enum Vp8Buffers {
     52     kAltRefBuffer = 0,
     53     kGoldenBuffer = 1,
     54     kLastBuffer = 2,
     55     kNoBuffer = 3  // Note: must be last.
     56   };
     57 
     58   enum Vp8BufferState {
     59     kBufferStartState,
     60     kBufferSent,
     61     kBufferAcked
     62   };
     63   struct BufferState {
     64     uint32 frame_id;
     65     Vp8BufferState state;
     66   };
     67 
     68   void InitEncode(int number_of_cores);
     69 
     70   // Calculate the max target in % for a keyframe.
     71   uint32 MaxIntraTarget(uint32 optimal_buffer_size) const;
     72 
     73   // Calculate which next Vp8 buffers to update with the next frame.
     74   Vp8Buffers GetNextBufferToUpdate();
     75 
     76   // Get encoder flags for our referenced encoder buffers.
     77   // Return which previous frame to reference.
     78   uint32 GetCodecReferenceFlags(vpx_codec_flags_t* flags);
     79 
     80   // Get encoder flags for our encoder buffers to update with next frame.
     81   void GetCodecUpdateFlags(Vp8Buffers buffer_to_update,
     82                            vpx_codec_flags_t* flags);
     83 
     84   const VideoSenderConfig cast_config_;
     85   const bool use_multiple_video_buffers_;
     86 
     87   // VP8 internal objects.
     88   scoped_ptr<vpx_codec_enc_cfg_t> config_;
     89   scoped_ptr<vpx_enc_ctx_t> encoder_;
     90   vpx_image_t* raw_image_;
     91 
     92   bool key_frame_requested_;
     93   bool first_frame_received_;
     94   base::TimeDelta first_frame_timestamp_;
     95   uint32 last_encoded_frame_id_;
     96   uint32 last_acked_frame_id_;
     97   uint32 frame_id_to_reference_;
     98   uint32 undroppable_frames_;
     99   BufferState buffer_state_[kNumberOfVp8VideoBuffers];
    100 
    101   // This is bound to the thread where Initialize() is called.
    102   base::ThreadChecker thread_checker_;
    103 
    104   DISALLOW_COPY_AND_ASSIGN(Vp8Encoder);
    105 };
    106 
    107 }  // namespace cast
    108 }  // namespace media
    109 
    110 #endif  // MEDIA_CAST_SENDER_CODECS_VP8_VP8_ENCODER_H_
    111