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• fixing (with ffmpeg) the chrominance position on a video after capturing

  23 mai 2016, par APLU

  I’m trying to convert some video from VHS to digital using an (old) video capture card (and obviously an old VHS player). Due to the input from my video capture card and the output available from the VHS, I have no other choice than capture with an S-Video cable to a computer.

  Almost everything works except a little mis-synchronization between chroma and luma which do not happen on TV.

  For example, in the original video, I have something like that :
  

  After capturing the video looks like this :
  

  As you may see, there is a little desynchronization of the chroma with the luma channel (I will say about 10 lines errors).

  I’m capturing with ffmpeg on a Linux system with the following commands :

  $ v4lctl setnorm PAL-BG

  $ v4lctl setinput S-video

  $ ffmpeg -y -f alsa -ac 2 -i pulse -f video4linux2 -i /dev/video0 -c:a pcm_s16le -vcodec rawvideo -t $duration -r 25 -loglevel error -stats /tmp/tmp.mkv

  I tried other input norm in v4l, tried an other VHS player, tried an other conversion cable from SCART to S-Video but it didn’t change anything,

  My question is simple : is there a way to fix this with a post-processing video filter in ffmpeg ?

  I already looked at the long list of video filter available in ffmpeg but I didn’t find anything.

  Also, please note I can’t apply filter during the capture commands (old capture cards, old cpu, ..), this is why I capture in rawvideo and native audio. When the capture is done I convert the video/audio into h264/vorbis, at this step I can apply as much as audio/video filtering needed (even if it include extracting chroma & luma to new files, fixing and merging again).

  Thanks !

• Revision 96419 : La librairie en version 1.9.2 v1.9.12 Add support for Direct Stream ...

  3 avril 2016, par kent1@… — Log

  La librairie en version 1.9.2
  v1.9.12
  Add support for Direct Stream Digital (DSD) / DSD Storage Facility (DSF) file format
  Add detection (not parsing) of WebP image format
  bugfix #1910 : Quicktime embedded images
  v1.9.11
  #64 - update constructor syntax for PHP 7
  #62 - infinite loop in large PNG files
  #61 - ID3v2 remove BOM from frame descriptions
  #60 - missing "break" in module.audio-video.quicktime.php
  #59 - .gitignore comments
  #58 - inconsistency in relation to module.tag.id3v2.php
  #57 - comparing instead of assign
  #56 - unsupported MIME type "audio/x-wave"
  #55 - readme.md variable reference
  #54 - QuickTime ? false 1000fps
  #53 - Quicktime / ID3v2 multiple genres
  #52 - sys_get_temp_dir in GetDataImageSize ?
  demo.joinmp3.php enhancements
  m4b (audiobook) chapters not parsed correctly
  sqlite3 caching not working
  bugfix #1903 - Quicktime meta atom not parsed

• ffmpeg - filter_complex list too long

  2 mars 2016, par Baumi

  Let’s say I want to overlay a clock in the video using special font, color, etc to video that is aprox 30 min long. I end up with command :

  ffmpeg -y -i in.mp4 -filter_complex "
  
  [0:v]drawtext=fontfile=/var/www/sites/manage/elements/digital-7.ttf:text='00\:00':fontcolor=white@1.0:fontsize=26:x=100:y=65:enable='between(t,0,7)'[tmp];
  
  [tmp]drawtext=fontfile=/var/www/sites/manage/elements/digital-7.ttf:text='00\:01':fontcolor=white@1.0:fontsize=26:x=100:y=65:enable='between(t,7,8)'[tmp]; 
  
  [tmp]drawtext=fontfile=/var/www/sites/manage/elements/digital-7.ttf:text='00\:02':fontcolor=white@1.0:fontsize=26:x=100:y=65:enable='between(t,8,9)'[tmp]; 
  
  [tmp]drawtext=fontfile=/var/www/sites/manage/elements/digital-7.ttf:text='00\:03':fontcolor=white@1.0:fontsize=26:x=100:y=65:enable='between(t,9,10)'[tmp]; 
  
  [tmp]drawtext=fontfile=/var/www/sites/manage/elements/digital-7.ttf:text='00\:04':fontcolor=white@1.0:fontsize=26:x=100:y=65:enable='between(t,10,11)'[tmp];
  
  ......." 
  
  -map "[tmp]" -map 0:a -acodec copy -c:v h264 out.mp4

  This clock is not the only overlay I have so finally I have end up with command 216kB long but this I cannot even run in bash because of argument list being too long.

  I wanted to re-encode the video only once. Is there any other way I can do that ?

  Thanks !