[FFmpeg-user] Multiple parts of a video

[Michael Koch]

Am 31.05.2022 um 20:27 schrieb Cecil Westerhof via ffmpeg-user:
> Michael Koch <astroelectronic at t-online.de> writes:
>
>> Am 31.05.2022 um 18:43 schrieb Cecil Westerhof via ffmpeg-user:
>>> Michael Koch <astroelectronic at t-online.de> writes:
>>>
>>>> I have a short example in chapter 2.57 of my book:
>>>> http://www.astro-electronic.de/FFmpeg_Book.pdf
>>> Just to make sure I understand it, I should do something like:
>>>       ffmpeg -ss %S1% -t %L1% -i %I1%     \
>>>              -ss %S2% -t %L2% -i %I1%     \
>>>              -ss %S3% -t %L3% -i %I1%     \
>>>              -lavfi "concat=n=3:v=1:a=0"  \
>>>              -an %OUT%
>>>
>>> But if I understand it well, this works on the iframes, would it not
>>> be better (but longer) to use:
>>>       ffmpeg -i %I1% -ss %S1% -t %L1%     \
>>>              -i %I1% -ss %S2% -t %L2%     \
>>>              -i %I1% -ss %S3% -t %L3%     \
>>>              -lavfi "concat=n=3:v=1:a=0"  \
>>>              -an %OUT%
>> I think that won't work. If you write the options after the input file,
>> then they are applied to the next input file, and the options in the
>> third line are applied to the output file.
>> The concat filter does also work with audio. I just didn't need audio in
>> my example.
> But if you put them before the input file they are not precise, but
> work on the iframe level. This can give quit extensive differences. (I
> was bitten by that in the past.) Or is that not the case in this
> specific scenario?
>

Then you could use the trim filter.

Michael