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• ffmpeg multiple pipes with different filters and outputs

  3 janvier 2024, par diegoddox

  I'm trying to pipe multiple outputs to an s3 but so far it's only working if I tried with only one pipe as soon as I add more I get Could not write header (incorrect codec parameters ?): Broken pipe error.

  


  aws s3 cp s3://bucket-name/original.mp4 - | \
  ffmpeg -f mp4 -i pipe:0 \
  -vf "scale=1280x720:flags=lanczos" -c:a aac -b:a 96k -movflags frag_keyframe+empty_moov -f mp4 pipe:1 | aws s3 cp - s3://bucket-name/720.mp4 --region my-region \
  -vf "scale=854x480:flags=lanczos" -c:a aac -b:a 96k -movflags frag_keyframe+empty_moov -f mp4 pipe:2 | aws s3 cp - s3://bucket-name/480.mp4 --region my-region \
  -vf "scale=640x360:flags=lanczos" -c:a aac -b:a 96k -movflags frag_keyframe+empty_moov -f mp4 pipe:3 | aws s3 cp - s3://bucket-name/360.mp4 --region my-region \
  -ss 00:00:00 -t 3 -vf "fps=10,scale=720:-1" -movflags frag_keyframe+empty_moov -f gif pipe:4 | aws s3 cp - s3://bucket-name/thumbnail.gif --region my-region


  


  Thanks in advance

  


• libavcodec/xsubenc.c : Fix bounding box coordinates

  7 novembre 2013, par Erik Olofsson

  libavcodec/xsubenc.c : Fix bounding box coordinates
  Fix coordinates of the lower right corner of the text area.
  
  Note that the coordinates are redundant as the size and
  
  position of the text area are known.
  
  Many decoders (including Sony Playstation 3, VLC and FFmpeg)
  
  ignore the redundant coordinates.
  
  Some hardware decoders need them for correct playback.
  Verified on Philips DVD player models HTS7201 and DVP3380.
  Fixes ticket #3031
  Signed-off-by : Erik Olofsson <eaj.olofsson@gmail.com>
  
  Reviewed-by : Reimar Döffinger <Reimar.Doeffinger@gmx.de>
  
  Signed-off-by : Michael Niedermayer <michaelni@gmx.at>
  

  • [DH] libavcodec/xsubenc.c

• Converting WebM audio to mp3 using ffmpeg and Rails

  30 avril 2021, par Garrett Bodley

  I created an online step sequencer and want to add functionality so that users can record the audio and save it as an mp3 on their local machine. I've been able to use the WebAudioAPI to record the sound generated in the browser window and send it to my Rails backend as a WebM blob. I am attempting to incorporate ffmpeg using the Streamio gem.

  


  How do I convert that blob to mp3 ? I'm planning on making a Recording model that belongs_to :user and has_one_attached :audio. I imagine I should use a before_save callback to process the blob ? What's confusing to me is that it seems streamio creates a new copy of the file when transcoding. How do I convert the blob to mp3 in place ?

  


  I've seen some posts where people call ffmpeg using system("ffmpeg code goes here") but I don't really understand how to grab the output so that ActiveStorage can link the resulting file to my models and whatnot.

  


  To add complexity to all of this is that I ultimately want to host this publicly and store the audio in a Cloudinary folder, which I imagine would change the process quite a bit. As you can tell I'm a bit confused as to how best to approach this problem. Any help would be greatly appreciated !