|
|
|
|
|
|
by matteocontrini
1931 days ago
|
|
|
>The best of the two worlds is to use input seeking for -ss and then output seeking for -to. Could you clarify what you mean with "use output seeking for -to"? From your Python script it seems that you're just using input seeking and then specifying the duration in seconds with `-t`, which is actually the same as using `-to` when doing input seeking. Also, input seeking should be inaccurate when doing stream copy, so I'm not sure your script actually works as expected? (And unless I'm missing something, it seems that all of this is well-explained in the ffmpeg guide linked above.) Thanks! |
|
|
In my Python script, I did input seeking for -ss (start point) part, and then output seeking for -t part (end point). As you can see, the -ss part is before -i {inputfile}, and -t is after.
-ss 1:00 -i file -t 5
is NOT the same as
-ss 1:00 -t 5 -i file.
The latter has a bug that happens frequently when I'm trimming MPEG-TS files recorded from HDTV. It literally doesn't stop at the -t/-to timestamp for reason I don't know. And it only happens when stream copy.
Below is a quick showcase: t.ts is the source, and the filenames show how I generate them with FFMPEG (for example, ss_t_i means input seeking -ss first, then -i t.ts, then -t 1:00).
https://i.imgur.com/lLUSzEM.png
As you can see, if I use -t/-to before -i, it doesn't cut the file properly.
>Also, input seeking should be inaccurate when doing stream copy
Yeah, it's not frame accurate, can only cut at keyframes, but enough for my application. By the way the same inaccuracy exists for output seeking if you're doing stream copy.