[FFmpeg-user] ffmpeg libx264 VBR and CBR output generates different POC, possible bug

Carl Eugen Hoyos cehoyos at ag.or.at
Tue Nov 20 10:58:07 CET 2012

Maxim Levkov <maxim.levkov <at> gmail.com> writes:

> I want to create CBR H.264 version of the video and VBR H.264 version.
> Once the video is done transcoding, I use the "elementary" core in
> commercial MPEG2 muxer for outputting MPEG2-TS file. When I exported
> MPEG2-TS and then analyzed with MPEG2-TS analyzer, I've noticed that
> explicit positions that I've indicated in FFMPEG are not being adhered to
> in CBR version of the file. Up on further analysis and more "explicit"
> output from FFMPEG, I've noticed that POC (picture order count) is
> different in CBR and VBR versions.

Assuming "picture order count" is a property of the 
(raw) h264 stream:
This sounds like a problem in x264 (if there is a problem, 
I don't know if that's the case). Did you already try to 
encode the "elementary core" with x264?
(Ideally by using a raw video as input stream to eliminate 
all other possible problem sources.)

Please do not top-post on this mailing list, it is considered 

Carl Eugen

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