Extracting "one of every 10 frames" in a video using VLC or FFmpeg

Solution 1:

Select 1 frame out of every 10 frames

You can use the select video filter in ffmpeg to do this:

ffmpeg -i input.mov -vf "select=not(mod(n\,10))" -vsync vfr -q:v 2 img_%03d.jpg

• For JPG output you can vary quality with -q:v. Effective range is 2 (best quality) to 31 (worst quality). You don't need this option if you want to output to PNG instead.

• This will output img_001.jpg, img_002.jpg, img_003.jpg, etc.

Solution 2:

The most important aspect in your question is the fact that the video uses 29.97 frames per second, not 30. Pesky NTSC.

Anyway, I think it would be easiest to just extract every frame, and then remove the ones you don't need:

ffmpeg -i 1.mov -y -f image2 -c:v mjpeg %03d.jpg

Then, remove the ones you don't need. Since every tenth frame will end with a 1.jpg, we can just take all the others …

find . -maxdepth 1 -not -iname "*1.jpg"

… and once you're sure these are the ones you want to remove:

find . -maxdepth 1 -not -iname "*1.jpg" -exec rm '{}' \;

If you can use mencoder, you could try the framestep option, as explained in the documentation, like framestep=10 in your case. I personally couldn't install/try it though.