[FFmpeg-user] PTS resolution

pdr0 pdr0 at shaw.ca
Tue Feb 23 21:05:47 EET 2021


Mark Filipak (ffmpeg) wrote
> In contrast, my best information so far is that, at least out of the
> encoder, ffmpeg encodes frames with PTS resolution = 1ms.

Not true;

Check the timestamps at each step. Decoding, prefilter, postfilter after
each filter, postencode. If you need to check timestamps inbetween filters,
use -vf showinfo.

If you export use a container timebase of 1/1000s such as mkv, then yes, you
are limited beacuse of the container timebase. That has nothing to do with
ffmpeg. If you've "ripped" a dvd using makemkv, for input into ffmpeg then
you start with a timebase of 1/1000s. That's not ffmpeg's fault either

The container timebase for a MPEG2-PS is 90K (or 1/90000s) .ie.  ffmpeg -i
input.vob tbn is 90k

tb:1/90000 fr:30000/1001 sar:8/9
pts_time:0
pts_time:0.0333556 
pts_time:0.0667222
pts_time:0.100089

(it's still wrong, it should have been )
tb:1/90000 fr:30000/1001 sar:8/9
pts_time:0
pts_time:0.0333667
pts_time:0.0667333
pts_time:0.1001

But the point is the "resolution" is finer than 1ms from decoding

But if you use DVD in MKV container input, the timebase reduces the "finer"
resolution to 1ms
tb:1/1000 fr:19001/317 sar:8/9
pts_time:0
pts_time:0.033
pts_time:0.067
pts_time:0.1







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