Comment by nickdothutton
4 days ago
FFmpeg is one of those tools I need to use so infrequently that he exact syntax never seems to stick. I've resorted to using an LLM to give me the command line I need. The only other tool that I ever had trouble with was 1990s-era MegaCLI from LSI Logic, also something I barely used from one year to the next (but one where you really need to get it right under pressure).
I've been using FFMPEG for 15+ years, and still can't remember almost any commands. LLMs have been amazing for using FFMPEG though. ChatGPT and Claude do wonders with "give me an ffmpeg command that will remux a video into mkv, include subtitle.srt in the file, and I only want it between 0:00:05 and 0:01:00." It produced this in case you were wondering: `ffmpeg -i input.mp4 -i subtitle.srt -ss 00:00:05 -to 00:01:00 -map 0 -map 1 -c copy -c:s mov_text output.mkv`
I wonder how small of an LLM you could develop if you only wanted to target creating ffmpeg commands. Perhaps it could be small enough to be hosted on a static webpage where it is run locally?
Perhaps small enough to include in ffmpeg itself so you can just write commands `ffmpeg do this thing I want`.
Now I say this, it seems like there should already be a shell that is also an LLM where you can mix bits of commands you vaguely remember and natural language a bit like Del Boy speaking French...
That would be an amazingly useful feature of ffmpeg, and considering how large its dependencies are (390MB of packages for `apt install ffmpeg` on a fresh Raspberry Pi OS install), it would be reasonable to have an optional model package.
Warp terminal does that. It's cool.
1 reply →
-c:s mov_text is unnecessary and in fact might be fucking things up
I was kind of curious about that one too. It is encoding the SRT into the MP4/MOV subtitle format. I use it all the time when muxing subs into MP4s, but I haven't seen what happens with an MKV like that. It is very well supported in MP4s.
I've just maintained my own note doc, going on 15 years now, of my most commonly used syntax. When that fails, I grep my bash history.
Same. The only thing that sticks is converting from format X to .mp4. Everything else I need to look up every single time.
Relevant XKCD https://xkcd.com/1168/
Yeah I commented the other day, tongue firmly in cheek, that it's probably worth burning down all the rainforests just so LLMs can tell me the right ffmpeg flags to do what I want.