[FFmpeg-user] Accurately video trim (fast)

[m.kog]

Hi!

I'm trying to trim video file accurately.

1. -ss and -t before -i:
ffmpeg -ss 00:00:05.000 -t 00:00:05.000 -i INPUT.MP4 -vcodec copy -acodec
copy -y OUTPUT.MP4

Result: ffmpeg cut file from 0 to 10 seconds. I think, there is no key
frames from 0 to 10 seconds.. I can't find other explanation for this fact.

2. -ss and -t after -i:
ffmpeg -i INPUT.MP4 -ss 00:00:05.000 -t 00:00:05.000 -vcodec copy -acodec
copy -y OUTPUT.MP4

Result: ffmpeg walk throug first 5 seconds and then encode next 5 seconds.
It's fast for 5 seconds.. But if -ss will be set to 00:55:05.000?

INPUT.MP4:  http://re-co.ru/i/1.mp4 http://re-co.ru/i/1.mp4 


So my question is: how to accurately and fast trim video files without
encoding.

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