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• Generating Gif from Mp4 directly - ffmpeg

  20 janvier 2016, par senty

  I am trying to generate a gif from an mp4 video file. I want to scale it and crop it while generating.

  I achieved that (cropping & scaling) from mp4 to mp4 with the below line , (so I can extract pngs with ffmpeg and use Imagick to make animated gif), but I believe there is a better way of achieving purely with ffmpeg.

  ffmpeg -i in.mp4 -filter:v "scale=300:ih*300/iw, crop=200:500:50:80" -c:a copy out.mp4

  My question is how to achieve the same this code is doing, but for directly generating gif from mp4.

  ---

  Then I started tweaking with mp4 to gif conversion, but when palette comes in, I couldn’t fully understand what’s going on.

  I found this answer and I made it work, however I couldn’t understand how to adapt scaling & cropping.

  $ ffmpeg -y -ss 30 -t 3 -i in.mp4 \
-vf fps=10,scale=320:-1:flags=lanczos,palettegen palette.png

  $ ffmpeg -ss 30 -t 3 -i in.flv -i palette.png -filter_complex \ "fps=10,scale=320:-1:flags=lanczos[x];[x][1:v]paletteuse" out.gif

  I partially understand what this bit does -y -ss 30 -t 3 -i in.mp4 (getting the first 30 seconds and generating a 3 second gif out of it). But for the next lines, I am completely lost what it is actually doing.

  It’d be amazing if someone can explain what each command does, or refer a link explaining this topic.

• Where to add FilterChain when using with Shell Script

  20 janvier 2016, par senty

  I am trying to get a jpg out of an mp4 video’s middle. I used this line and it works like charm for generating jpg thumbnail in one line :

  ffmpeg -i input.mp4 -vcodec mjpeg -vframes 1 -an -f rawvideo -ss `ffmpeg -i input.mp4 2>&1 | grep Duration | awk '{print $2}' | tr -d , | awk -F ':' '{print $3/2}'` output.jpg

  However, I want to apply scaling and cropping a filter chain (filter:v) with the above line, but where ever I put the filter, I couldn’t make it work.

  -filter:v "scale=720:ih*720/iw, crop=720:720:280:1000".

  Where should I put it ?

  The errors I receive :

  At least one output file must be specified

  Invalid duration specification for ss: -filter:v

  Please note that this works :

  ffmpeg -i fkj.mp4 -vcodec mjpeg -filter:v "scale=720:ih*720/iw, crop=720:720:280:1000" -vframes 1 -an -f rawvideo -ss 4  output.jpg

• Sendcmd not recognizing filter instance names on linux

  27 février 2024, par DanHabib

  I'm using sendcmd to update my crops to follow a specific object around a screen.

  


  It works perfectly on my mac
It fails on my AWS Lambda function.

  


  This issue only occurs when I add an instance name like crop@crop_0
When I don't use instance names it works only on the first input video.

  


  My actual command is more complicated and has multiple input crops so i need instance names.

  


  I must run this in a single command.

  


  Both environments are running ffmpeg 6

  


  ffmpeg -y -i input.mp4 -filter_complex "[0:v]trim=start=0.0:end=75.92,setpts=PTS-STARTPTS,crop@crop_0=606:1080:798.36:0[v0];[0:a]atrim=start=0.0:end=75.92,asetpts=PTS-STARTPTS[a0];[v0]sendcmd=f=file.txt[sndcmd_pad]" -fps_mode vfr -map [sndcmd_pad] -map [outa] output.mp4


  


  What could cause sendcmd to work perfectly on mac and fail on linux only when instance names are used ?