FFmpeg by Example

> "convert this mov to mp4"

Did any of the commands look like the ones in the left window:

https://beta.gitsense.com/?chats=12850fe4-ffb1-4618-9215-c13...

The left window contains a summary of all the LLMs asked, including all commands. The right window contains the individual LLM responses.

I asked about gotchas with missing libraries as well, and Sonnet 3.5 said there were. Were these the same libraries that were missing for you?

My feelings exactly, but I think that's OK!

It's another tool and one that might actually improve with time. I don't see GNU's man pages getting any better spontaneously.

Whoa, what if they started to use AI to auto-generate man pages...

Hate to be that guy, but which LLM was doing the generation? GPT-4 Turbo / Claude 3.x have not really let me down in generating ffmpeg commands - especially for basic requests - with most of their failures resulting from domain-specific vagaries that an expert would need to weigh in on m

Just like all other code. There will be user-respecting open source code and tools, and there's user-disrespecting profitable closed code that makes too many decisions for you.

But possibly the most rewarding. The struggle is its own reward that pays off later many times over.

I use regexes a lot. The main thing that always trips me up is dealing with escaping, because different tools I use – vim, sed, rg, and so on – sometimes have different meanings for when to escape or not.

In one tool you’ll use + to match one or more times, and \+ to mean literal plus sign.

In another tool you’ll use \+ to match one or more time, and + to mean literal plus sign.

In one tool you’ll use ( and ) to create a match group, and \( and \) to mean literal open and close parentheses.

In another tool you’ll use \( and \) to create a match group, and ( and ) to mean literal open and close parentheses.

This is basically the only problem I have when writing regexes, for the kinds of regexes I write.

Also, one thing that’s not a problem per se but something that leads me to write my regexes with more characters than strictly necessary is that I rarely use shorthand for groups of characters. For example the tool might have a shorthand for digit but I always write [0-9] when I need to match a digit. Also probably because the shorthand might or might not be different for different tools.

Regexes are also known to be “write once read never”, in that writing a regex is relatively easy, but revisiting a semi-complicated regex you or someone else wrote in the past takes a little bit of extra effort to figure out what it’s matching and what edits one should make to it. In this case, tools like https://regex101.com/ or https://www.debuggex.com/ help a lot.

No one doubts the power or utility of regexes or ffmpeg, but they are both complicated beasts that really take a lot of skill.

They're both tools where if they're part of your daily workflow you'll get immense value out of learning them thoroughly. If instead you need a regex once or twice a week, the benefit is not greater than the cost of learning to do it myself. I have a hundred other equally complicated things to learn and remember, half the job of the computer is to know things I can't put in my brain. If it can do the regex for me, I suddenly get 70% of the value at no cost.

Regex is not a tool I need often enough to justify the hours and brain space. But it is still an indespensible tool. So when I need a regex, I either ask a human wizard I know, or now I ask my computer directly.

in 15 years it never sticks and by the time i need it again i've forgotten it! :D

My rule for using LLMs is that anything that's one off is okay. Anything that's more permanent and committed to a repo needs a human review. I strongly suggest you have an understanding of the basics (at least the box model) so that you are competent at reviewing CSS code before using LLM for that.

I've been looking for a good guide on prompting LLMs for CSS.

does anyone know of any?

Interesting. Yes, I assume that's possible although I'm not sure how you handle the background- I guess you find an empty frame, and subtract that from every image with a plane.

One of the advantages of working with image data is that movies are really just 3d data and as long as all the movies you work with are the same size, if you have enough ram, or use dask, you could basically do this in a couple lines of numpy.

Fascinating, it didn't occur to me quality could take a hit, I thought the flag merely meant "perform h264 encoding over here"

Edit: relevant docs from ffmpeg, they back up your perception, and now I'm left to wonder how much I want to learn about profiles in order to cut up these videos. I suppose I'll run an overnight job to reencode them from Avi to h264 at high quality, and make sure the scene detect script is only doing copys, not reencoding, since that's the part I'm doing interactively, there's no real reason I should be sitting at the computer while its transcoding.

Hardware encoders typically generate output of significantly lower quality than good software encoders like x264, but are generally faster and do not use much CPU resource. (That is, they require a higher bitrate to make output with the same perceptual quality, or they make output with a lower perceptual quality at the same bitrate.)

[0] https://trac.ffmpeg.org/wiki/HWAccelIntro

I get that. My critique is for the library authors, not you.

Warp terminal does that. It's cool.