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• ffmpeg determine frame number for fade filter

  16 juin 2016, par Gert Gottschalk

  I am looking for an easy way to set the time points for the fade filter. Particularly for the fade-out at the end. At best would be a time based format. I understand the fade filter works based on frames. But is there a way to change that to time stamp ? Particularly in the end I have a hard time getting the number of the last frame. Some means to tell the fade filter to start the fade 0.5sec before the end would be awesome. Maybe something like :

  -filter:v 'fade=out:-0.5:0.3'

  Read : ’start fade out 0.5sec before end and have fade take 0.3sec. I.e. have 0.2sec of black at the end.

  I would also be OK if this would be in frame number counts.

  My grief right now is that the frame count i.e. reported by ffprobe seems to be somewhat half of what it really is. A fade filter applied on the count provided by ffprobe turn my video to black about half-way through the clip. I’m not sure what I’m missing there.

  Again my primary question is : How to determine the correct frame number for the fade out filter ?

  Thanks,
  Gert

• ffv1enc_vulkan : implement RCT search for level >= 4

  20 novembre 2024, par Lynne

  ffv1enc_vulkan : implement RCT search for level >= 4
  

  • [DH] libavcodec/ffv1enc_vulkan.c
  • [DH] libavcodec/vulkan/Makefile
  • [DH] libavcodec/vulkan/ffv1_enc_setup.comp
  • [DH] libavcodec/vulkan/ffv1_rct_search.comp

• FFMPEG Motion Compensation and Search

  20 juin 2016, par Tina Jasmin

  I’m trying to modify the motion detection part of FFMPEG. What I want to do is to extend the search space, so that whenever the macroblock hit the right most edge of the frame, I need it to still move the block towards the left-most as if they are connected (in my example videos, the right edge is actually a continue of the left edge). Can someone help me to point where exactly I can modify it within FFMPEG source code or x265, or x264 ?

  

  I took H265 as an example from here. It has a motion.cpp file which nicely specifies the possible block sizes as below. But I can’t find the specific loop that traverses the frame. A help is highly appreciated.

  #define SETUP_SCALE(W, H) \
  
      sizeScale[LUMA_ ## W ## x ## H] = (H * H) >> 4;
  
      SETUP_SCALE(4, 4);
  
      SETUP_SCALE(8, 8);
  
      SETUP_SCALE(8, 4);
  
      SETUP_SCALE(4, 8);
  
      SETUP_SCALE(16, 16);
  
      SETUP_SCALE(16, 8);
  
      SETUP_SCALE(8, 16);
  
      SETUP_SCALE(16, 12);
  
      SETUP_SCALE(12, 16);
  
      SETUP_SCALE(4, 16);
  
      SETUP_SCALE(16, 4);
  
      SETUP_SCALE(32, 32);
  
      SETUP_SCALE(32, 16);
  
      SETUP_SCALE(16, 32);
  
      SETUP_SCALE(32, 24);
  
      SETUP_SCALE(24, 32);
  
      SETUP_SCALE(32, 8);
  
      SETUP_SCALE(8, 32);
  
      SETUP_SCALE(64, 64);
  
      SETUP_SCALE(64, 32);
  
      SETUP_SCALE(32, 64);
  
      SETUP_SCALE(64, 48);
  
      SETUP_SCALE(48, 64);
  
      SETUP_SCALE(64, 16);
  
      SETUP_SCALE(16, 64);
  
  #undef SETUP_SCALE

  UPDATE :

  One way to do that (in x265) is to modify the edge extension area (which is already in the code, in the frameFilter.cpp), and do that for rightmost and fill blocks with leftmost pixels. I identified the piece of code here. Can someone help me to add this feature for right-to-left extension ?

  if ((col == 0) | (col == m_frameFilter->m_numCols - 1))
  
      {
  
          // TODO: improve by process on Left or Right only
  
          primitives.extendRowBorder(reconPic->getLumaAddr(m_rowAddr), stride, reconPic->m_picWidth, realH, reconPic->m_lumaMarginX);
  
  
  
          if (m_frameFilter->m_param->internalCsp != X265_CSP_I400)
  
          {
  
              primitives.extendRowBorder(reconPic->getCbAddr(m_rowAddr), strideC, reconPic->m_picWidth >> hChromaShift, realH >> vChromaShift, reconPic->m_chromaMarginX);
  
              primitives.extendRowBorder(reconPic->getCrAddr(m_rowAddr), strideC, reconPic->m_picWidth >> hChromaShift, realH >> vChromaShift, reconPic->m_chromaMarginX);
  
          }
  
      }
  
  
  
      // Extra Left and Right border on first and last CU
  
      if ((col == 0) | (col == m_frameFilter->m_numCols - 1))
  
      {
  
          copySizeY += lumaMarginX;
  
          copySizeC += chromaMarginX;
  
      }
  
  
  
      // First column need extension left padding area and first CU
  
      if (col == 0)
  
      {
  
          pixY -= lumaMarginX;
  
          pixU -= chromaMarginX;
  
          pixV -= chromaMarginX;
  
      }