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• FFMPEG add circular mask to videos, convert to black and white and concatenate

  3 mai 2018, par Yassine

  Hello everyone i’m a beginner and i would appreciate your help.

  I’m making a mobile application that generates custom video resumes based on the user’s videos taken from his phone, the user has to upload 5 different videos to the server from the mobile application, in the server side i want to :

  • Add a .png circular mask to each video.
  • Make each video black and white.

  • Concatenate the videos with other already existing title videos
    (e.g [userVideo1] [title1] [userVideo2] [title2]...) Visual Example

    [Edit : I would like more features]

  • Add background music
  • Add watermark logo in the middle
  • Remove silent footage from the beginning and from the end
  • Some input videos might be rotated, i want to rotate videos back to normal if they are rotated.

  So far i managed to add the circular mask, make the videos black and white and concatenate 3 videos including a premade title video, but the second user video has no sound in the output.

  This is the script i ended up with :

  ffmpeg -i uservid1.mov -i uservid2.mp4 -i mask.png -i title1.mp4  -preset 
  
  ultrafast -filter_complex "
  
  
  
  [2:v][0:v]scale2ref[s1][s2];     
  
  [s2][s1]overlay[vid1];  
  
  [2:v][1:v]scale2ref[s3][s4]; 
  
  [s4][s3]overlay[vid2];  
  
  [vid1]hue=s=0[v0]; 
  
  [vid2]hue=s=0[v1];  
  
  [v0]scale=720x400[in0]; 
  
  [v1]scale=720x400[in1]; 
  
  [3:v]scale=720x400[in3]; 
  
  [in0]setsar=sar=0[final0]; 
  
  [in1]setsar=sar=0[final1];      
  
  [in3]setsar=sar=0[final3]; 
  
  [final0][final3][final1]concat=n=3;"
  
  
  
  -codec:a copy finalCV.mp4  

• How to get an accurate duration of any audio file quickly ?

  27 septembre 2023, par Steve M

  There are many audio files in the wild encoded with VBR which don't have an accurate duration tag, and command line FFMpeg would output the following :

  



  


  Estimating duration from bitrate, this may be inaccurate

  


  



  (and indeed, it is)

  



  Using libav, we can see that this is tested with the has_duration() function from libavformat/utils.c

  



  I have an audio player that needs to get an accurate duration information using libav. I've tried completely decoding the file and counting the total number of samples decoded which is the usual recommendation (and is accurate), but this can take 10+ seconds on a 60 minute audio file, which is not acceptable.

  



  I notice that there are some closed source audio decoders and music playing apps which can get an accurate duration for these files immediately. There must be some cheap way of determining the accurate duration ? Perhaps a snippet or high-level description would help me out.

  


• Quickly split videos into parts with ffmpeg

  20 avril 2021, par RewossKy

  I'm doing splitting on FFMPEG. I divide 1.5 hour videos into 30 minutes. I have two ways of partitioning, the first is the method of rendering by recodecing on the top, I do not have any problem in this, but the time is quite long despite the GTX 1660s graphics card and the ryzen5 3500x processor.

  


  At the bottom, the time is short, but the first 3-4 seconds of the second part videos are frozen. Sometimes this causes problems like not reading in video editing programs.

  


  With recodec (slow, no problem)
ffmpeg -i 1.mp4 -vcodec libx264 -crf 30 -ss 00:00:00 -t 00:29:30 s1.mp4
ffmpeg -i 1.mp4 -vcodec libx264 -crf 30 -ss 00:29:31 -t 00:29:30 s2.mp4
ffmpeg -i 1.mp4 -vcodec libx264 -crf 30 -ss 00:59:01 -t 00:29:30 s3.mp4
ffmpeg -i 1.mp4 -vcodec libx264 -crf 30 -ss 01:28:30 -t 00:29:30 s4.mp4

  


  Without recodec (fast but have problem sometimes)
ffmpeg -i 1.mp4 -vcodec copy -ss 00:00:00 -t 00:29:30 s1.mp4
ffmpeg -i 1.mp4 -vcodec copy -ss 00:29:31 -t 00:29:30 s2.mp4
ffmpeg -i 1.mp4 -vcodec copy -ss 00:59:01 -t 00:29:30 s3.mp4
ffmpeg -i 1.mp4 -vcodec copy -ss 01:28:30 -t 00:29:30 s4.mp4