grep and use multiple lines from output

jpifer · 01-14-2024, 02:42 PM

I'm trying to grep for info from ffmpeg, then use that to re-run ffmpeg. Hoping someone can help me combine this and make it work.

If I run this:
ffmpeg -i "input.mkv" 2>&1 | grep "Stream #" | grep eng

I get this for example:
Stream #0:2(eng): Audio: ac3, 48000 Hz, 5.1(side), fltp, 448 kb/s
Stream #0:4(eng): Subtitle: hdmv_pgs_subtitle

I would like to pull the 0:2 and 0:4 (or more of them if there are) then run ffmpeg again using them as parameters.

Any help is appreciated.

Thank!

syg00 · 01-14-2024, 09:52 PM

I'd be mighty surprised if there isn't an option to get (only) that data directly from ffmpeg itself. It seems to have all the bells and whistles - others will be able to answer that.
If I had to do it without that knowledge I'd use sed. Something like this should work - presumes exactly the layout above, no exceptions.

Code:

ffmpeg -i "input.mkv" 2>&1 | sed -rn 's/Stream #([0-9]+:[0-9]+).eng.+/\1/p'

Turbocapitalist · 01-14-2024, 11:03 PM

There is also ffprobe.

Code:

ffprobe -show_streams -select_streams v input.mkv

ffprobe -show_streams -select_streams v:1 input.mkv

etc.

jpifer · 01-17-2024, 12:40 PM

Thanks for the help. Your replies got me on a good track.