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• ffmpeg failed to drawbox and set volume

  27 janvier 2021, par Hussam Al-Barodi

  I don't know what is wrong in my command with ffmpeg.
Lets say I have a video and I want to make a black screen with muted audio between 20-30 seconds. So what I wrote is :

  


  ffmpeg -i input.mp4 -filter_complex "[0:v]trim=0:20[0v];[0:a]atrim=0:20[0a];[0:v]trim=20:30,drawbox=color=black:t=fill[1v];[0:a]atrim=20:30,volume=0[1a];[0:v]trim=30:60[2v];[0:a]atrim=30:60[2a];[0v][1v][2v]concat=n=3:v=1:a=0[outv];[0a][1a][2a]concat=n=3:v=0:a=1[outa]" -map [outv] -map [outa] output.mp4


  


  Now, I expect to have a video with 1 min length where the seconds between 20 & 30 are muted with black screen, but what I got is :

  


  20 sec correct
20 sec freezing video with no audio
40 sec black video with no audio
30 sec correct


  


  Can anyone help and tell me what is wrong in the command line ?

  


• FFMPEG Concatenate multiple videos causes : Too many invisible frames

  2 décembre 2019, par Silmood

  i’m trying to concatenate multiple .webm files in a single one. One of these files is a simple black video generated with the next command :

  ffmpeg -f lavfi -i color=c=black:s=1920x1080:d=5.2 black.webm

  Then this is concat_list.txt

  file 'black.webm'
  
  file '1.webm'
  
  file '2.webm'
  
  file '3.webm'

  Finally i try to concatenate files with :

  ffmpeg -f concat -i concat_list.txt -c copy video.webm

  The result is a long list of this message :

  [AVBSFContext @ 0x7fcecef00180] Too many invisible frames
  
  [AVBSFContext @ 0x7fcecef00180] Failed to receive packet from filter vp9_superframe for stream 0

  Complete log

  The problem seems to be the black.webm file. I removed it from the concat_list.txt and everything works fine.

  It’s important to mention that none of these files has an audio stream.

• Video stream analysis on the fly - advise ?

  12 août 2020, par jakkolwiek

  I'm planning to develop a simple solution that would able me to perform a very basic video stream analysis on the fly. I've never done anything like that before, hence the very general and open question. The main focus is on checking if the stream is going without problems like - freeze frames, black screens and if the audio is there. Sync is out of scope. I read about open libraries like OpenCV and Xuggler, but they seem more complex than for my needs. FFmpeg is able to detect black screens, but not on the fly.

  



  Is there any other open lib I could look into ? Could you advise me anything ? I'm thinking about using Java or Python. Or maybe both. Efficiency of the solution is out of scope, I'm focusing now only on freeze frames and black screens detection.

  



  Any advise is welcome !

  



  Best regards, 
Peter