Recherche avancée

Sur d’autres sites (13153)

• Detect Windows Phone 8 in Desktop mode to filter out false positives for file upload support.

  18 juillet 2013, par blueimp

  Detect Windows Phone 8 in Desktop mode to filter out false positives for file upload support.
  Thanks to Achim Stöhr for the findings.
  

• 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;
  
      }

• ffmpeg : check video folder conformance with bash file

  1er février 2018, par Massimo Vantaggio

  I wrote a small bash file that reads a folder, generates a playlist, concatenates, adds a logo and encode the big video result for dash ready, i would like to implement it by checking before all videos conformance : if they have same fps, same resolution, same time base etc.
  Below my situation :

  #!/bin/bash
  
  # CONCAT DEMUXER
  
  #This demuxer reads a list of #files and other directives from a text file and demuxes them one after the other, as if #all their packets had been muxed together. All files must have the same streams (same #codecs, same time base, etc.) but can be wrapped in different container formats.
  
  
  
  times=()
  
  for f in *.mp4; do
  
      _t=$(ffmpeg -i "$f" 2>&1 | grep "Duration" | grep -o " [0-9:.]*, " | head -n1 | tr ',' ' ' | awk -F: '{ print ($1 * 3600) + ($2 * 60) + $3 }')
  
      times+=("$_t")
  
  done
  
  TOTALDURATION=$( echo "${times[@]}" | sed 's/ /+/g' | bc )
  
  
  
  
  
  printf "file '%s'\n" *.mp4 > playlist.txt
  
  ffmpeg -auto_convert 1 -f concat -safe 0 -i playlist.txt -c:a aac -b:a 384k -ar 48000 -ac 2 -async 1 -c:v libx264 -x264opts 'keyint=50:min-keyint=50:no-scenecut' -r 25 -b:v 2400k -maxrate 2400k -bufsize 1200k -vf "scale=-1:432" -vf "movie=stable.png [watermark]; [in][watermark] overlay=main_w-overlay_w-10:10 [out]" -t $TOTALDURATION out.mp4
  
  #clear
  
  echo “VIDEO CONCAT COMPLETED”

  For example below i find this bash that calculate the total duration in second of the videos of the folder

  times=()
  
  for f in *.mp4; do
  
      _t=$(ffmpeg -i "$f" 2>&1 | grep "Duration" | grep -o " [0-9:.]*, " | head -n1 | tr ',' ' ' | awk -F: '{ print ($1 * 3600) + ($2 * 60) + $3 }')
  
      times+=("$_t")
  
  done
  
  TOTALDURATION=$( echo "${times[@]}" | sed 's/ /+/g' | bc )

  I wish to check if the videos have the same fps, and same resolution before process
  Thanks
  Massimo