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• How to get info on a partial incoming mov file in javascript ? [closed]

  30 août 2020, par David542

  I'm not sure if this is more a JavaScript question or ffmpeg, but suppose I have a scenario where a user is uploading a 100GB file. And, before they upload it (or actually, as soon as we detect the first few frames or whatever), we want to make sure that it is a "valid" file — let's say for this question we want to verify that it is :

  


  

  • 29.97 fps

  


  • Video bitrate > X

  


  • Codec of com.apple.finalcutstudio.prores

  


  


  What would be the best way to do this ? I was thinking something like :

  


  

  1. A user clicks the upload button and selects their file.

  


  2. We upload the first 1MB of that file to our server — check that using ffmpeg (how to ignore errors or something with ffmpeg ?)

  


  3. If the file passes our initial checks we upload the entire video file. If not, we raise a warning to the end user and stop the upload.

  


  


  How could this process be done ? I am seeking a JavaScript snippet (JS Fiddle ?) and a backend snippet (to receive the partial input and issue the ffmpeg commands).

  


• how to extract multi frame with ffmpeg exact and fast

  24 février 2018, par Questioner

  i want extract frame from video with ffmpeg

  for example

  ffmpeg.exe -an -r 21 -ss 00:17:50 -i "K :\test.mkv" -t 00:00:30 -s 560x314 -q:v 1 "T :\GIF\test_%05d.png"

  the command what i intend is

  extract frame from K :\test.mkv(O)
  start at 00:00:30 (O)
  extracted image size is 560x314 (o)
  output path and file name format T :\GIF\test_%05d.png (O)

  extract 30seconds from start point -t 00:00:30 (X)
  with frame rate 21(so if video’s original fps is 24fps, then it reduced to fps22)(maybe ? X)

  anyway this is not collect

  i got 660 images, image number is collect but this is not 30seconds video data
  only 15seconds data
  too large error, so i can’t ignore it

  i think i can fix it by -ss move to after -i
  but this need really a lot of time..

  how can i solve this problem
  1 5second error is ok but error is too large

• FFmpeg : concat multiple videos, some with audio, some without

  13 février 2020, par Tommy Adeniyi

  I’m trying to concatenate 5 videos where the first and last have no audio track. I have tried the following command :

      ffmpeg -i 1-copyright/copyright2018640x480.mp4 -i 2-openingtitle/EOTIntroFINAL640x480.mp4 -i 3-videos/yelling.mp4 -i 4-endtitle/EOTOutroFINAL640x480.mp4 -i 5-learnabout/Niambi640.mp4 -filter_complex "[0:v:0] [0:a:0] [1:v:0] [1:a:0] [2:v:0] [2:a:0] [3:v:0] [3:a:0] [4:v:0] [4:a:0] concat=n=5:v=1:a=1 [v] [a]" -map "[v]" -map "[a]" output_video.mp4

  and I get the output error :

      Stream specifier ':a:0' in filtergraph description [0:v:0] [0:a:0] [1:v:0] [1:a:0] [2:v:0] [2:a:0] [3:v:0] [3:a:0] [4:v:0] [4:a:0] concat=n=5:v=1:a=1 [v] [a] matches no streams.

  I know the first and last videos have no audio but I dont know how to write the statement to ignore the audio track in those videos. I have tried removing the [0:a:0] but that just throws another error :

     Stream specifier ':v:0' in filtergraph description [0:v:0] [1:v:0] [1:a:0] [2:v:0] [2:a:0] [3:v:0] [3:a:0] [4:v:0] [4:a:0] concat=n=5:v=1:a=1 [v] [a] matches no streams.

  It doesnt make sense and Im kinda lost.