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• Concatenating video clip with static image causes buffer errors

  16 février 2020, par jgaeb

  I’m trying to concatenate a 15 second clip of a video (MOVIE.mp4) with 5 seconds (no audio) of an image (IMAGE.jpg) using FFmpeg.

  Something seems to be wrong with my filtergraph, although I’m unable to determine what. The command I’ve put together is the following :

  ffmpeg \
  
  -loop 1 -t 5 -I IMAGE.jpg \
  
  -t 15 -I MOVIE.mp4 \
  
  -filter_complex "[0:v]scale=480:640[1_v];anullsrc[1_a];[1:v][1:a][1_v][1_a]concat=n=2:v=1:a=1[out]" \
  
  -map "[out]" \
  
  -strict experimental tst_full.mp4

  Unfortunately, this seems to be creating some strange results :

  1. On my personal computer (FFmpeg 4.2.1) it correctly concatenates the movie with the static image ; however, the static image lasts for an unbounded length of time. (After entering ctrl-C, the movie is still viewable, but is of an extremely long length—e.g., 35 min—depending on when I interrupt the process.)

  2. On a remote machine where I need to do the ultimate video processing (FFmpeg 2.8.15-0ubuntu0.16.04.1), the command does not terminate, and instead, I get cascading errors of the following form :

  Past duration 0.611458 too large
  
  ...
  
  [output stream 0:0 @ 0x21135a0] 100 buffers queued in output stream 0:0, something may be wrong.
  
  ...
  
  [output stream 0:0 @ 0x21135a0] 100000 buffers queued in output stream 0:0, something may be wrong.

  I haven’t been able to find much documentation that elucidates what these errors mean, so I don’t know what’s going wrong.

• How do you generate a looping animated gif for Facebook with ffmpeg

  7 février 2020, par Alan W. Smith

  When I paste a giphy url (like this one) into a facebook post or comment, the gif plays immediately and loops indefinitely. When I upload ones I make from ffmpeg, neither of those things happen. You have to click a play button to start the animation and then it ends after one time through.

  I have a couple of ffmpeg commands I use to create the gifs. They are :

  ffmpeg -ss 10 -t 5  -i input.m4v -vf "fps=15,scale=800:-2:flags=lanczos,palettegen" -y palette.png

  and

  ffmpeg -ss 10.6 -t 5 -i input.m4v -i palette.png -filter_complex "fps=15,scale=800:-1:lanczos[video];[video][1:v]paletteuse" output.gif

  The first one generates a custom color pallet that’s used by the second one to create a high quality animated gif. I’ve also tried adding -loop 0 (i.e. ffmpeg -ss 10.6 -t 5 -i input.m4v -i palette.png -filter_complex "fps=15,scale=800:-1:lanczos[video];[video][1:v]paletteuse" -loop 0 output.gif) but that didn’t work either.

  I also tried uploading the ffmpeg generated images to a personal website and calling them from there but those didn’t load at all.

  In case it helps, here’s a copy of one of the gifs (which autostarts and loops on StackOverflow for me but not on FB)

  

  How does one go about creating a gif that will autostart and loop indefinitely for facebook ?

  (Note : I’ve got no problem if I need to do something with a personal website, but I don’t want to use Giphly or the other animated gif sites directly if at all possible. Also worth pointing out that I discovered if I download the image from giphly and upload it, it doesn’t autostart either. So, this may be something internal to FB, but I’d still like to figure that out.)

• Convert file with any extension to MP4 with ffmpeg

  15 novembre 2019, par not legit

  I am using youtube-dl and ffmpeg to create a youtube downloader and converter (for personal use). I am trying to download a video and convert it to MP4.

  The problem I have, is that youtube-dl downloads the video in a variety of formats. Is there a way that I can download the video and then tell FFMPEG to convert it, not knowing the current file type ?

  I tried using a * wild card but that results in an error.

  @echo off
  
  title youtube downloader
  
  
  
  set /p name= URL: 
  
  echo Select a type. (vid/mp3/mp4)
  
  set /p type=
  
  
  
  IF /i "%type%"=="vid" goto vid
  
  IF /i "%type%"=="mp3" goto mp3
  
  IF /i "%type%"=="mp4" goto mp4
  
  
  
  :vid
  
  youtube-dl %name%
  
  goto commonexit
  
  
  
  :mp3
  
  youtube-dl -x --audio-format mp3 %name%
  
  goto commonexit
  
  
  
  :mp4
  
  youtube-dl -o video %name%
  
  ffmpeg -i video.* video.mp4 -hide_banner
  
  
  
  :commonexit
  
  pause