[FFmpeg-user] Can this trigger VBR encoding for x264, x265, and libvvenc ?

Aditya Dandavate adityadandavate04 at gmail.com
Fri Nov 1 16:34:10 EET 2024


No, unfortunately, opening the .lmp files 2nd time is not possible :(

Fine, I'll use your recommended rate control method. 👍

On Fri, 1 Nov, 2024, 6:12 pm Ferdi Scholten, <ferdi at sttc-nlp.nl> wrote:

> Sorry for top-posting 🙏
> > My content is gaming content, and I record the gameplay in form of .lmp
> > files.
> >
> > When a command ( which isn't related to ffmpeg ) is given from a batch
> > file, the gameplay starts being played back.
> >
> > During the playing back of the gameplay, the audio and video are encoded
> > simulataenously.
> >
> > So, even if I wish, I can't use 2 pass encoding.
> >
> > So, which option from the 2 should I stick to ? CVBR or ABR ?
> >
> > On Fri, 1 Nov, 2024, 3:35 pm Ferdi Scholten,<ferdi at sttc-nlp.nl>  wrote:
> >
> >> Also, in general case, for gaming content, between CVBR and ABR, which
> >>> provides better quality at same filesizes ?
> >>>
> >>> On Wed, 30 Oct, 2024, 7:40 pm Ferdi Scholten,<ferdi at sttc-nlp.nl>
>  wrote:
> >>>
> >>>> Okay, thank you sir.
> >>>>> Should I keep the bufsize 5 times that of maxrate ? Will that help in
> >>>>> effective allocation of bitrates ? Also, for getting the best
> possible
> >>>>> quality in this case, how high should be the value of bufsize ? What
> is
> >>>>> your recommendation ?
> >>>>>
> >>>>>     (I use the slow preset for both x264 and x265 for getting better
> >>>> quality
> >>>>> at same filesizes btw).
> >>>>>
> >>>>> On Wed, 30 Oct, 2024, 6:25 pm Ferdi Scholten,<ferdi at sttc-nlp.nl>
> >>   wrote:
> >>>>>> If I set " -b:v 5000k -maxrate 6000k -minrate 4000k " for x264, x265
> >> and
> >>>>>>> vvenc, will this enable VBR encoding for these three encoders ?
> >>>>>>> _______________________________________________
> >>>>>>>
> >>>>>> If "constrained VBR" is what you want then the answer is yes.
> >>>>>>
> >>>>>> It is not true VBR because it will never get below minrate or above
> >>>>>> maxrate even if it would be possible/necessary for maintaining the
> >>>>>> encoding quality
> >>>>>> _______________________________________________
> >>>>>>
> >>>> try to see it like this, the bufsize/maxrate is the frequency at which
> >>>> ffmpeg checks for the need of changing the bitrate.
> >>>> This is of course highly dependent on the type of content you have.
> >>>> Detailed content with high motion and/or lots of scene changes will do
> >>>> best with bufsize = maxrate, while for more static content bufsize can
> >>>> be >= 5 times maxrate.
> >>>> _______________________________________________
> >>>>
> >> First, please stop top posting in this list! read the guidelines for
> >> posting!
> >>
> >> Second to answer your question: It all depends on the content. There is
> >> no general "best quality type of encoding"
> >>
> >> If you want the best quality for your given constraints (filesize and/or
> >> bitrate) and you are not live streaming you should always use multiple
> >> pass encoding,
> >> if you are live streaming, read this:
> >> https://trac.ffmpeg.org/wiki/StreamingGuide
> >>
> >> _______________________________________________
> >>
> If you can replay the .lmp file more than once you can use multi pass
> encoding.
>
> Otherwise I would use single pass cfr for encoding with the desired
> quality, maybe with max-bitrate set.
> -crf 16 is a good starting point if you want high quality encodes in x265
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