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• convert video to audio - ffmpeg

  2 mai 2024, par shakti goyal

  I'm trying to convert video to audio using ffmpeg in flutter based application but command is not working.

  


  Is there something wrong with the command ?

  


    void convert(File pickedVideo) async {
    Directory applicationDocDirectory = await getApplicationDocumentsDirectory();

    final outputPath = '${applicationDocDirectory.path}/output-audio-${const Uuid().v1()}.mp3';

    final session = await FFmpegKit.execute('-i ${pickedVideo.path} -vn -acodec mp3 $outputPath');

    final returnCode = await session.getReturnCode();

    print(ReturnCode.isSuccess(returnCode)); // return false
  }


  


• ffmpeg join multiple audio with acrossfade filter

  30 avril 2017, par alditis

  I have audio file multiple :

  001.ogg, 002.ogg, ..., 100.ogg

  I need join the files with overfade filter between they.

  I did it two in two a cumulative way :

  ffmpeg -i 001.ogg -i 002.ogg -filter_complex acrossfade=d=3:o=1:c1=tri:c2=tri -b:a 128k -o r01.ogg
  
  ffmpeg -i r01.ogg -i 003.ogg -filter_complex acrossfade=d=3:o=1:c1=tri:c2=tri -b:a 128k -o r02.ogg
  
  ffmpeg -i r02.ogg -i 004.ogg -filter_complex acrossfade=d=3:o=1:c1=tri:c2=tri -b:a 128k -o r02.ogg
  
  
  
  ....
  
  ffmpeg -i r98.ogg -i 100.ogg -filter_complex acrossfade=d=3:o=1:c1=tri:c2=tri -b:a 128k -o final.ogg

  But final.ogg does not have good sound on the firsts songs (less quality while more cumulative).

  How can I avoid less quality in the final.ogg ?

  Other way is concat but : How do you define the filter acrossfade using concat ?

  ffmpeg -i "concat:1.ogg|2.ogg|...|100.ogg" copy final.ogg

• ffmpeg cut video and burn subtitle in a single command

  3 janvier 2020, par razvan

  I want to cut a piece out of a video and burn subtitle in that piece.

  I can do this in 3 steps :

  1. cut the video
     ffmpeg -ss 25:00 -to 26:00 -i vid.mp4 -c copy out.mp4

  2. cut the subtitle
     ffmpeg -i sub.srt -ss 25:00 -to 26:00 out.srt

  3. burn subtitle in the video piece
     ffmpeg -i out.mp4  -vf subtitles=out.srt  -c:a copy -y final.mp4

  But I want to do this in a single ffmpeg command.

  If I do this
  ffmpeg -ss 25:00 -to 26:00 -i vid.mp4   -vf subtitles=sub.srt  -c:a copy -y final.mp4
  the video is cut but no subtitle is burned into it.
  This is fast.

  If I do this
  ffmpeg  -i vid.mp4  -ss 25:00 -to 26:00 -vf subtitles=sub.srt  -c:a copy -y final.mp4
  the video is cut and subtitles burned correctly,but there is a delay in starting writing the final.mp4.
  I think ffmpeg is processing vid.mp4 from the beginning till it reach the -ss time (and drop that part)
  then continue processing and writing it to final.mp4

  Is there a way to do this fast and in a single ffmpeg command ?
  Like ffmpeg going directly to -ss time and cut that, process it, burn subtitle in it.

  Thanks