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• How to use subtitles filter to a video VFR ( variable frame rate ) video ? [migrated]

  14 février 2019, par iaaflaafc

  I have created a VFR (variable frame rate) video from a list of images by using the following ffmpeg command.

  ffmpeg -f concat -i concat.txt -vsync vfr -pix_fmt yuv420p output.mp4

  where the concat.txt is a text file which contains the list of the image locations and durations in the below format.

  file image01.png
  
  duration 3
  
  file image02.png
  
  duration 5
  
  file image02.png

  I have a subtitle file (.srt file) that I would like to add to the generated video by using the subtitles filter.

  I tried to use the subtitles filter by running the following command

  ffmpeg -i output.mp4 -codec:a copy -vf subtitles=subtitles.srt -max_muxing_queue_size 4096 outputWithSubtitles.mp4

  I find that the resultant output file does not show any subtitles.

  I find that if instead of VFR video if constant frame rate video is generated, then this issue is not observed i.e., during the generation of the first video from images if -vsync vfr option is not used, then a constant frame rate video is generated and using subtitles filter works.

  Is there a way to use the subtitles filter on a VFR video ?

• Creating image overlay on video like tiktok on a video in flutter [closed]

  12 octobre 2020, par Sarthak Singhal

  I am trying to create an app in flutter in which user can add image on a video like the given screenshot. The user should be able to move the image widget anywhere on the screen, resize it, and rotate it also. When this is done, the image should be merged on the video.

  


  For now I have used Stack and MatrixGestureDetector to let the user move the images on the screen.

  


  I want to know how to merge this image along with the exact scale, rotation and position as seen on the screen.

  


  Also if I am going in wrong direction then please guide me the right way to do image overlay on a video in flutter like that of tiktok or snapchat.

  


  

  


• Ruby Video Upload - Cocaine error when trying to transcode video

  21 janvier 2015, par Scottagecheeze

  I am having a bit of trouble when it comes to transcoding a video being uploaded by Paperclip to S3. I have tried both gem 'paperclip-ffmpeg' and gem 'paperclip-av-transcoder. Both fail when I try to add a new style :

  :styles => {
  
      :medium => { :geometry => "640x480", :format => 'flv' }
  
    }, 
  
    :s3_credentials => {:bucket => ENV['S3_BUCKET_NAME'], :access_key_id => ENV['ACCESS_KEY_ID'], :secret_access_key => ENV['SECRET_ACCESS_KEY']},
  
    :processors => [:ffmpeg],
  
    :path => ":id/:style/:style_:basename.:extension"

  I am able to upload my video as is but I am not able to transcode them. Here is the error that it gives me, sorry for the link, I am not able to post images yet.

  Essentially I want to be able to upload a video in any format and transcode it into a specific format. Any help is greatly appreciated.

  Thanks