Seek -ss accuracy

Questions involving a Windows version of FFmpeg.
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mingonn
Posts: 1
Joined: Wed Apr 12, 2017 12:01 am

Seek -ss accuracy

Post by mingonn » Wed Apr 12, 2017 12:56 am

Hi all,

Need to extract frames at an exact points (100ms accuracy) but having trouble. Documentation says
Note that in most formats it is not possible to seek exactly, so ffmpeg will seek to the closest seek point before position.
so it sounds like its not possible with ffmpeg so I though I would double check.

I have tried the following and a couple of other variants but is most cases stepping forward 100ms still gives me the same frame of starting point in the resulting clip. Looking at the results seeks resolution seems to be to the nearest second?

ffmpeg -ss 10.45 -i "C:\Video Analysis\1\1\Produce_6.mp4" -t 2 -c copy "C:\Video Analysis\1\1\Frames\0.MP4"
ffmpeg -ss 00:00:10.450 -i "C:\Video Analysis\1\1\Produce_6.mp4" -frames:v 1 "C:\Video Analysis\1\1\Frames\0.jpg"

Is it an issue with the video? Can I add more seek positions? Have 100s of videos and seek positions so doing this manually is not an option.

Hope someone has been here before and there is an easy fix.

llogan
Posts: 332
Joined: Fri Mar 14, 2014 3:29 am

Re: Seek -ss accuracy

Post by llogan » Thu Apr 20, 2017 7:50 pm

You need to cut on keyframes if you want to use "-c copy".
For your second command try using "-ss" as an output option.

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