[FFmpeg-user] Where to cut audio by video frame?

[Ted Park]

> And from the documentation I should use -ss as an output option to be
> accurate. But what is with -t? As input or output?

They do different things depending on if it’s used as an input option or output option. I don’t think -ss would make a difference where you put -ss but -t is the duration, as an input option, it’s the duration of the file read, and as an output option it’s the duration of the output. With the math in your command it looks like it’s meant to be an output option. You might also want to take a look at -to.

Though I have to wonder how calculating based on frames is going to work out. It’s not in a vob, so you’re basically calculating the time in seconds it takes before the 2928’th frame in the video shows up, and getting the duration of how long (5177-2928) frames take up, all in seconds. I don’t know if I’d expect the timestamps to be synced up so nicely.