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• speed up the video and audio 1.5 times ffmpeg [duplicate]

  23 février 2021, par Mayank Thapliyal

  I have a video which I want to speed up 1.5 times. I gave a check on stackoverflow but I did not got the perfect answer for me (sometimes audio disappears,sometimes audio remains unaffected). I want to speed up my video(including audio) 1.5 times.

  


  Also,if possible, can the command be combined with this command into a single command(I guess it would save my processing time)

  


  ffmpeg -i video$.mp4 -filter_complex "[0]crop=iw:ih/2:0:0[top];[0]crop=iw:ih/2:0:oh[bottom];[top][bottom]hstack" -preset fast -c:a copy video.mp4

  


  Thanks in advance

  


• can we runtime change video playback speed using ffmpeg ? [closed]

  17 février 2021, par vbv_at_gd

  I am trying to create video player application which has one feature that change runtime playback speed for example if user set playback speed (using seekbar value) then video play in slow-motion of fast forward for that particular time.

  


  But FFMPEG create new video and so i want to avoid new video creation every time.

  


• Is there a way to speed up audio processing (amix and adelay) in FFMPEG ?

  30 mars 2017, par Nadir

  I’m using, in android application, many ffmpeg amix and adelay filter commands over very small mp3 files (not longer than 3 seconds).
  Unfortunately each adelay or amix command takes between 2 and 4 seconds to execute, which is a lot considering that I should run the same operation for a lot of files.
  Here are two example of commands I’m running :

  amix :

  [-i, input1.mp3, -i, input2.mp3, -filter_complex, amix=inputs=2:duration=longest:dropout_transition=0,dynaudnorm=f=100[aout], -map, [aout], -ac, 2, -c:a, libmp3lame, -q:a, 4, output.mp3]

  adelay :

  [-i, input3.mp3, -filter_complex, [0:a]adelay=1|1, -c:a, libmp3lame, output1.mp3]

  I know in video there is an option (-preset ultrafast) to make the execution faster, is there a way to do the same for audio ?