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• Ffmpeg color opacity

  19 janvier 2016, par Sandra

  I tried to rotate a video and keep the unused place due to the rotation transparent, to be able to overlay it later and to do that, I suppose that if the color was transparent is will be right ; and in the official page (https://www.ffmpeg.org/ffmpeg-filters.html#rotate) they said that you can give a color that ffmpeg would use in place of unused place due to the rotation of the video. So I tried, relatively to https://www.ffmpeg.org/ffmpeg-utils.html#Color to put a color with these commands

  ffmpeg -i video.mp4 -vf "rotate=PI/6:fillcolor=red@0.0" -acodec copy output.mp4

  and

  ffmpeg -i video.mp4 -vf "rotate=PI/6:fillcolor=red@0x00" -acodec copy output.mp4

  And it doesn’t work. The color remain opaque, and that whatever the value of the opacity (0.0 to 1.0)

  Any of you can know what is happened ?

• avcodec/libjxlenc : prevent color encoding from being set twice

  13 avril, par Leo Izen

  avcodec/libjxlenc : prevent color encoding from being set twice
  We currently populate the color encoding bundle and then check to see
  
  if there's an ICC profile to attach, and set the color encoding bundle
  
  in either case. The ICC profile overrides the color encoding bundle, so
  
  we should not calculate enum-based color encoding if we have an ICC
  
  profile present. Fixes several unnecessary warnings from being emitted.
  Signed-off-by : Leo Izen <leo.izen@gmail.com>
  

  • [DH] libavcodec/libjxlenc.c

• ffmpeg concat makes video async over time

  25 septembre 2018, par jvecsei

  I have multiple files like these two shown below (always input_X.tmp.avi and input_X_tmp.start.avi) which i want to concat. The video/audio are in sync in these files.

  Over time the resulting file gets async. I’ve been searching on stackoverflow for multiple hours now trying out different parameters like

  • async 1
  • vsync 1
  • async 25
  • fflags +genpts

  and so on. But I can’t find a solution to my problem.

  ffmpeg -f concat -fflags +genpts -i concat.txt -c:a copy -c:v copy -y out.avi

  When I re-encode the audio stream everything is fine. However, I would prefer if there was a solution without re-encoding the audio. Maybe someone has an advice what I have to change to make this work.

  File 1 :

  Input #0, avi, from 'input_0.tmp.avi':
  
    Metadata:
  
      encoder         : Lavf58.12.100
  
    Duration: 00:33:59.36, start: 0.000000, bitrate: 1002 kb/s
  
      Stream #0:0: Video: h264 (High) (H264 / 0x34363248), yuv420p(tv, bt470bg, progressive), 720x576 [SAR 64:45 DAR 16:9], 797 kb/s, 25 fps, 25 tbr, 25 tbn, 50 tbc
  
      Stream #0:1: Audio: mp3 (U[0][0][0] / 0x0055), 48000 Hz, stereo, fltp, 192 kb/s

  File 2 :

  Input #0, avi, from 'input_0.tmp.start.avi':
  
    Metadata:
  
      encoder         : Lavf58.12.100
  
    Duration: 00:00:11.59, start: 0.000000, bitrate: 428 kb/s
  
      Stream #0:0: Video: h264 (High) (H264 / 0x34363248), yuv420p(progressive), 720x576 [SAR 64:45 DAR 16:9], 220 kb/s, 25 fps, 25 tbr, 25 tbn, 50 tbc
  
      Stream #0:1: Audio: mp3 (U[0][0][0] / 0x0055), 48000 Hz, stereo, fltp, 192 kb/s

  Result :

  Input #0, avi, from 'out.avi':
  
    Metadata:
  
      encoder         : Lavf58.12.100
  
    Duration: 02:05:40.56, start: 0.000000, bitrate: 975 kb/s
  
      Stream #0:0: Video: h264 (High) (H264 / 0x34363248), yuv420p(progressive), 720x576 [SAR 64:45 DAR 16:9], 770 kb/s, 25 fps, 25 tbr, 25 tbn, 50 tbc
  
      Stream #0:1: Audio: mp3 (U[0][0][0] / 0x0055), 48000 Hz, stereo, fltp, 192 kb/s

  The different files i got from input_X...avi are a mix of files I just cut with/without re-encoding from the same file.