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• How do I force an IDR-frame using the x264 C API ?

  28 octobre 2020, par Keith

  I am attempting to use an external bool signal to force the next encoded frame to be an IDR-frame using the x264 C API. I am using the "baseline" profile with the "ultrafast" and "zerolatency" presets. I tried to use the input pic settings prior to encoding, as in this code snippet, but this has not worked. My class Open() and Encode() methods are shown here. Any help will be appreciated.

  


  int X264Encoder::Open(void)
{
  if (_x264VideoEncoder != NULL)
    Close();

  // Set up default parameters.
  if (x264_param_default_preset(&_param, _encoderSpeedPreset.c_str(), "zerolatency") < 0)  // 0=success, -1=failed
    { _errStr = "X264Encoder::Open: Default parameter preset failed with " + _encoderSpeedPreset; return(0); }

  // Set non-default params.
  _param.i_bitdepth       = 8;
  _param.i_csp            = _colourSpaceMapping[_colourSpace]; // Input colour space
  if(!_param.i_csp)
    { _errStr = "X264Encoder::Open: Incompatible colour space " + to_string(_colourSpace); return(0); }
  _param.i_width          = _width;
  _param.i_height         = _height;
  _param.i_fps_num        = _videoRateNumerator;
  _param.i_fps_den        = _videoRateDenominator;

  _param.rc.i_bitrate     = _avgBitsPerSecond / 1000; // bitrate units are in kbits/s

  _param.i_threads        = 1;
  _param.b_vfr_input      = 0;  // VFR input.  If 1, use timebase and timestamps for ratecontrol purposes. If 0, use fps only.
  _param.b_repeat_headers = 1;  // Put SPS/PPS before each keyframe
  _param.b_annexb         = 1;  // If set, place start codes (4 bytes) before NAL units, otherwise place size (4 bytes) before NAL units.

  // Apply profile restrictions.
  if (x264_param_apply_profile(&_param, _profile.c_str()) < 0)  // 0=success, -1=failed
    { _errStr = "X264Encoder::Open: Unable to set profile " + _profile; return(0); }

  // Initialise the encoder input pic buffer.
  if (x264_picture_alloc(&_picIn, _param.i_csp, _param.i_width, _param.i_height) < 0)
    { _errStr = "X264Encoder::Open: Unable to alloc input picture buffer"; return(0); }
  _inPicIsAllocated = true;

  // Instantiate the encoder.
  _x264VideoEncoder = x264_encoder_open(&_param);
  if (_x264VideoEncoder == NULL)
  {
    _errStr = "X264Encoder::Open: Unable to instantiate the encoder"; 
    // Clean up before exit.
    x264_picture_clean(&_picIn);
    _inPicIsAllocated = false;
    return(0);
  }//end if !_x264VideoEncoder...

  // Frame counting for pts timestamps.
  _frameNum     = 0;
  _lastPicType  = 0; // IDR-frame

  d.clear();

  return(1);
}//end Open.

int X264Encoder::Encode(void* pSrc, void* pCmp, void* codeParameter)
{
  _encodedFrameSize = 0;

  // Validation house work.
  if(!Ready())
    { _errStr = "X264Encoder::Encode: Not ready"; return(0); }

  if(!pSrc || !pCmp)
    { _errStr = "X264Encoder::Encode: Invalid function parameter list"; return(0); }

  // Load input image. 
  if(_param.i_csp != X264_CSP_I420) // Can only process I420 input colour space.
    { _errStr = "X264Encoder::Encode: I420 colour space required"; return(0); }
  uint32_t lumSize = _width * _height;
  uint32_t chrSize = lumSize / 4;
  // Transfer the input source image into the x264 picture img structure.
  uint8_t* pImg = static_cast(pSrc);
  memcpy_s(_picIn.img.plane[0], lumSize, pImg, lumSize);
  pImg += lumSize;
  memcpy_s(_picIn.img.plane[1], chrSize, pImg, chrSize);
  pImg += chrSize;
  memcpy_s(_picIn.img.plane[2], chrSize, pImg, chrSize);

  // Encode single frame
  _picIn.i_pts = _frameNum;
  if (_idrFrameRequired) 
  {  
    _picIn.i_type = X264_TYPE_IDR; 
    //... and clear the signal.
    _idrFrameRequired = false; 
  }//end if _idrFrameRequired...
  else 
    _picIn.i_type = X264_TYPE_AUTO;

  _encodedFrameSize = x264_encoder_encode(_x264VideoEncoder, &_nal, &_nalCnt, &_picIn, &_picOut);
  if (_encodedFrameSize > 0)
  {
    // Write the encoded stream to the output.
    uint8_t* pOut = static_cast(pCmp);
    memcpy_s(pOut, _encodedFrameSize, _nal->p_payload, _encodedFrameSize);
  }//end else if _encodedFrameSize...
  else
    { _errStr = "X264Encoder::Encode: Encode process failed"; return(0); }

  _lastPicType = 1; // Non-IDR
  if (_picOut.i_type == X264_TYPE_IDR)
    _lastPicType = 0; // IDR

  d.push_back({ _encodedFrameSize, _lastPicType });

  _frameNum++;
  return(1);
}//end Encode...


  


• h264 : Split h264-test off into a separate file - golomb-test.c.

  30 janvier 2012, par Diego Biurrun

  h264 : Split h264-test off into a separate file - golomb-test.c.

• h264 : Split h264-test off into a separate file - golomb-test.c.

  30 janvier 2012, par Diego Biurrun

  h264 : Split h264-test off into a separate file - golomb-test.c.