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• How to merge multiple video files into one video only

  1er août 2017, par shamaleyte

  I have multiple webm video files of a conference call.
  However, each participant joined the call at a different time which resulted in the fact that each video file has a different startTimeOffset values.

  Video Start Time

  Video1 : 00:00

  Video2 : 00:10

  Video3 : 01:40

  My purpose is to play back this conference. However, I do not record the conference as 1 video, it is recorded with multiple video files, instead.
  Is there any best practice to stitch such videos accordingly ?
  Maybe by ffmpeg library ?

  There is also a paid solution ; https://aws.amazon.com/about-aws/whats-new/2016/11/amazon-elastic-transcoder-adds-support-for-clip-stitching/ ) to merge video fragments to a single clip, this will make the client-side much simpler. But any free practice of doing it ?

  The expected outcome is to have 1 video showing 3 videos in a grid.
  When ffmpeg stitches the videos, it should consider their start time values properly so that the videos are played accordingly.

• Move metadata from end of video to start of video ?

  25 octobre 2013, par Ahmed Nawaz

  I am recording video using javacv(ffmpeg and open cv) then cutting and merging with mp4parser. Then converting from H263 to H264 using Javacv. After doing these all things getting my required video with a little problem that metadata is on the end of file due to ffmpeg and I can't play video progressively. I am able to move data on pc using qt-faststart after that my video is fine. However I want to move data from end to start in my android application is it possibal to move data using mp4parser or some other library in android ??

  I have tried followings.

  recorder.setVideoOption("-movflags", "faststart"); 
  
  recorder.setVideoOption("movflags", "faststart"); 
  
  recorder.setVideoOption("movflags", "+faststart"); 

• Extract image from video in Python using ffmpeg and subprocess

  13 juin 2021, par Mevon

  Me and a friend are currently working on a twitter bot which uploads images taken from randomly chosen video files.
  
We are using ffmpeg, with subprocess.call(), to get out.jpg from a video file,
  
which is working fine when the subtitles are hardcoded into the video.
  
We've also made it burn the subtitles into the out.jpg outside of python, but when trying it inside pyhton with subprocess.call() it won't work and it will say :

  


  Output /file/path/to/file.mkv same as Input #0 - exiting
FFmpeg cannot edit existing files in-place.


  


  This is the code for harcoded subtitles.

  


  subprocess.call(
        ['ffmpeg', '-y', '-ss', str(randomTime), '-i', filepath, '-vframes', '1', '-vf', 'scale=1920:1080', '-q:v', '1',
         '-qmin', '1', tmpfilename])


  


  And this the code for non hardcoded subtitles.

  


  subprocess.call(
        ['ffmpeg', '-y', '-ss', str(randomTime), '-copyts', '-i', filepath, '-vf', 'subtitles', filepath, '-vframes', '1', '-vf', 'scale=1920:1080',
         '-vf', '-q:v', '1', '-qmin', '1', '-frames:v', '1', tmpfilename])


  


  Also both me and my friend are not so sure if calling ffmpeg using subprocess.call() is the right way to do it in python.
  
Any kind of help is welcome and please ask me for more code or more details if needed.