Recherche avancée

Sur d’autres sites (6937)

• Revision 37431 : Désormais, le plugin de mutualisation fait non seulement la mise à jour de ...

  19 avril 2010, par real3t@… — Log

  Désormais, le plugin de mutualisation fait non seulement la mise à jour de SPIP, mais *aussi* la mise à jour des plugins (particulièrement utile pour passer de SPIP 2 à SPIP 2.1 avec des extensions/ )

• How to re-encode to rgb pixel_format properly in ffmpeg

  1er février 2020, par captain_majid

  I’m using this command to record from multiple inputs :

  ffmpeg -y
  
  -f dshow -rtbufsize 1024M -thread_queue_size 1024 -probesize 64M -i video="screen-capture-recorder" -framerate 30
  
  -f dshow -rtbufsize 16M -i audio="virtual-audio-capturer"
  
  -f dshow -rtbufsize 16M -i audio="Microphone (DroidCam Virtual Audio)"
  
  -f dshow -rtbufsize 512M -thread_queue_size 512 -probesize 50M -i video="DroidCam Source 3"
  
  -stream_loop -1 -i ".\media\background sounds\blue.mp4"
  
  -i ".\media\pictures\Webcam Overlay\blue_.png"
  
  -i ".\media\pictures\Webcam Overlay\red.png"
  
  -f gdigrab -rtbufsize 512M -thread_queue_size 512 -probesize 64M -itsoffset 0.80 -i title="NohBoard v1.2.2" -framerate 60 -draw_mouse 0
  
  
  
  -filter_complex "
  
  [0:v] scale=1366x768 [desktop];
  
  [3:v] hue=s=-5, scale=240x160 [webcam];
  
  [desktop][webcam] overlay=x=W-w-285:y=H-h-7:format=rgb [deskCam];
  
  [4:v] format=rgba,colorchannelmixer=aa=0.5, scale=240x160 [vid];
  
  [deskCam][vid] overlay=x=W-w-5:y=H-h-245:format=rgb [deskCamVid];
  
  [deskCamVid][5:v] overlay=x=W-w-280:y=H-h-0:format=rgb [deskCamVidBlue];
  
  [deskCamVidBlue][6:v] overlay=x=W-w-0:y=H-h-238:format=rgb [deskCamVidBlueRed];
  
  [7:v] chromakey=0x00FF00:similarity=.200, scale=420x140 [kb];
  
  [deskCamVidBlueRed][kb] overlay=x=W-w-945:y=H-h-285:format=rgb [final];
  
  [1][2] amix [aud1]; [1][2][4] amix=inputs=3 [aud2]"
  
  -map "[final]" -map "[aud1]" -map "[aud2]" -metadata:s:a:0 title="No Music" -metadata:s:a:1 title="All sounds" out.mkv

  The problem is the colors are not as bright as I want unless adding :format=rgb to all overlays like seen above, but this delays my encoding a lot, also when I press ’Q’, only a small part of the video (like 1m of 3m) is produced.

  Also If you see any unnecessary switches or non-optimal ones, please advise.

• ffmpeg -ss then apply filter then concat producing timestamp errors

  6 août 2020, par Bob Ramsey

  Using ffmpeg, I have split a file into multiple parts using -ss. Then I apply a filter to some of the files, then concat the files back together. When I do that, I get : Non-monotonous DTS in output stream 0:0 ; previous : 341334, current : 340526 ; changing to 341335. This may result in incorrect timestamps in the output file. The output file plays, but there are noticeable skips where the files are joined.

  


  Here's how I am splitting the file :

  


  ffmpeg -i full_source.mp4 -ss 0 -to 14.264250 -c copy  01-plain.mp4
ffmpeg -i full_source.mp4 -ss 14.264250 -to 18.435083 -c copy  01-filtered.mp4

ffmpeg -i full_source.mp4 -ss 18.435083 -to 29.988292 -c copy  02-plain.mp4
ffmpeg -i full_source.mp4 -ss 29.988292 -to 31.865167 -c copy  02-filtered.mp4
...
ffmpeg -i full_source.mp4 -ss 0 -to 14.264250 -c copy  10-plain.mp4
ffmpeg -i full_source.mp4 -ss 234.484203 -to 300.000 -c copy  10-filtered.mp4


  


  Then I apply a different drawtext filter on each of the 10 filtered files and save them with a new name, like :

  


  ffmpeg -hide_banner -loglevel warning -y -i 01-filtered.mp4 -filter_complex "drawtext=fontfile=calibri.ttf:fontsize=24:fontcolor=white:x=300:y=500:text='hello world'" -crf 15 01-filtered-complete.mp4


  


  Finally, I join all of the plain and complete files back together like this :

  


  ffmpeg  -f concat -safe 0 -i mylist.txt -c:a copy -c:v copy  outfile.mp4


  


  And that's where the timing error comes in. I've tried adding -vsync drop in the concat command, but that didn't really work either. Same version of ffmpeg does the split, the filter, and the concat. I've tried different versions, everything from 20170519 to one from May 2020 with the same result. Always making sure that all three steps are done by the same version of ffmpeg.

  


  The only thing I can see is that ffprobe shows a duration of 14.27 for 01-plain.mp4 when it should be 14.264250. All of the other files show a similar rounding difference. The files are 23.98 fps. If I do all of my filters in really long command without splitting the file, I can use the more precise numbers with no problem. It just takes 10 times as long. This is all scripted, it happens a couple of hundred times a day and time is money, so I can't take 10 times as long to do each file.

  


  Any ideas ? Thanks in advance !