[FFmpeg-user] Trying to solve drop in quality
ealarcong at gmail.com
Tue Nov 3 23:45:09 EET 2020
El mar., 3 nov. 2020 a las 18:36, John Harlow via ffmpeg-user (<
ffmpeg-user at ffmpeg.org>) escribió:
> The -g is definitely the quality problem. I tried setting it various to
> 30*1000/1001, 60*1000/1001 120*1000/1001, 180*1000/1001, 360/1000/1001and
> even 15*1000/1001.
> Any of those changes show up in mediainfo as:
> Format settings : CABAC / 4 Ref Frames
> Format settings, CABAC : Yes
> Format settings, Reference frames : 4 frames
> I would have thought the interval for the ref frames was either 2 seconds
> (60*1000/1001) or 2 per ts segment
> which would be (basically) 180*1000/1001.
> I'm not sure how to get to Reference Frames 2.
> -g is the gop size in frames, integer, not time, if you want a key frame
every 2 seconds you should use -g 60, when using 30fps.
With gop 2, you are getting a keyframe every 2 frames, so basically your
video is a huge collection of jpeg images
More information about the ffmpeg-user