[x265] Artifacts with vbv-init/vbv-end

[Diego Pasqualin]

Hi Alex, thank you for your reply,

I tried 0.9 and got the same issue. In fact I even tried without segmenting
the video, just adding vbv-init and vbv-end and encoding the entire video
at once.
vbv-end-fr-adj can only be enabled if the total number of frames is known.
The '--frames' option seems to be CLI only (see below), and the '-frames:v'
from ffmpeg is not recognized by x265 (shouldn't it be?).

If I try to use frames=15866
[libx265 @ 0x49c7240] Unknown option: frames.

If I try to add -framed:v to ffmpeg:
x265 [error]: vbv-end-fr-adj cannot be enabled when total number of frames
is unknown

Em qui., 29 de out. de 2020 às 19:34, Alex Giladi <alex.giladi at gmail.com>
escreveu:

> Hi Diego,
> I would try 0.9 as opposed to 0.5 on both vbv-init and vbv-end.
> There is also an optional --vbv-end-fr-adj parameter, you may want to
> play with it. May want to tune it, 12+ frames is best at hiding the
> stitch point.
> Best,
> Alex.
>
> On Thu, Oct 29, 2020 at 12:23 PM Diego Pasqualin <dpasqualin at gmail.com>
> wrote:
> >
> > Hi, I'm revisiting some parameters in our chunked encoding pipeline and
> I stumbled upon vbv-init and vbv-end, which seems to be recommended for the
> use case (https://x265.readthedocs.io/en/3.1/cli.html#cmdoption-vbv-init).
> However, if I set these two parameters I get really bad artifacts,
> strangely more intense in the right bottom part of the output video. I took
> this screenshot as example https://pasteboard.co/JxVhD78.png
> >
> > This is the full ffmpeg command. If I remove the vbv-init/vbv-end it
> encodes nicely without artifacts. Any idea on what might be going on? Thank
> you very much!
> >
> > ffmpeg -fflags +genpts -i big-buck-bunny.mp4 -map 0:v -bf 3 -refs 3 -crf
> 21 -force_key_frames expr:gte(t,n_forced*2) -g 50 -keyint_min 50
> -x265-params
> "hrd=1:vbv-init=0.5:vbv-end=0.5:vbv-maxrate=1870:vbv-bufsize=3740:keyint=50:min-keyint=50:no-open-gop=1:bframes=3:ref=3:level=40:limit-modes=1:rect=1:amp=1"
> -c:v libx265 -flags +cgop -map_chapters -1 -map_metadata -1 -pix_fmt
> yuv420p -preset medium -profile:v main -r 25 -vsync cfr -sws_flags bicubic
> -filter:v scale=trunc((oh*iw*sar/ih)/2)*2:720 -an -dn -sn -y ./output.mp4
> > _______________________________________________
> > x265-devel mailing list
> > x265-devel at videolan.org
> > https://mailman.videolan.org/listinfo/x265-devel
> _______________________________________________
> x265-devel mailing list
> x265-devel at videolan.org
> https://mailman.videolan.org/listinfo/x265-devel
>
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://mailman.videolan.org/pipermail/x265-devel/attachments/20201029/487672f2/attachment.html>