[FFmpeg-user] Ynt: Ynt: Mailman privacy alert

Carl Zwanzig cpz at tuunq.com
Tue Dec 29 20:05:40 EET 2020

(Next time you post, please fix the "privacy alert" in the subject line; 
that doesn't belong.)

On 12/29/2020 5:57 AM, MERT Gürtürk wrote:
> I have a 30 fps video file.I will use this process for geotagging. 

Actually, you have a 29.97fps (or 30000/1001) file (aka "drop-frame" rate).

> I want to set this file to produce 1 image per second (starting from the
> first image). My video duration is 8.51 minutes in total.
Assuming the duration listed is correct (00:08:51.54 = 531.45 sec), in 
source frames that would be about 15930 source frames with that half-second 
included. That half second might get you an extra output frame.

Referring to some official doc (which really wasn't hard to find)

use the fps video filter

ffmpeg -i NTSC_Test.mov -vf fps=1 x\%04d.jpg

Using a frame-count marked 2-second (00:00:02.0) file I get frames 0.14 and 
1.14 (in the middle of each second). If you need to get the first frame of 
each second, you may need to experiment with the 'select' filter.

Examples from using -r (for anyone searching the archive)
ffmpeg -i NTSC_Test.mov  -r 1 x\%04d.jpg
gives frames 000, 0.01, 0.26, and 1.26

ffmpeg -i NTSC_Test.mov -ss 00:00:00.1 -r 1 x\%04d.jpg
gives frames 0.03, 0.04, 0.29, and 1.29



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