[x264-devel] Re: no gain in 2PASS for very low bitrates

[shauli rozen]

since you mentioned video encoding guides , do you have any good ones
which you can publish here the links to?


On 12/25/05, Guillaume POIRIER <poirierg at gmail.com> wrote:
>
> Hi,
>
> On 12/25/05, Robert Swain <robert.swain at gmail.com> wrote:
> > Hey,
> >
> > On 12/25/05, Guillaume POIRIER <poirierg at gmail.com> wrote:
> > > Hi,
> > > On 12/25/05, Patrick Lefevre <pat at wischip.com> wrote:
> > > > I have used 10,000 frames content (with bunch of scene changes) @
> 30fps
> > > > in 2 pass mode. 1080p is still excellent quality down to 2Mb (4Mb
> peak).
> > > > What is considered low bit-rate?]. For playback, I used mplayer,
> > > > otherwise the decoding filter appears too slow (?), at least if used
> > > > with mediaplayer. [1221 snapshot]
> > >
> > > My definition low low bitrate is when you encode a DVD size video with
> > > a bit per pixel ratio lower than 0.9 with a H.264 codec. Some ppl
> > > won't agree with that as it widely depends on what kind of quality you
> > > target.
> >
> > I think you mean 0.09 bpp. :) But of course we both know that's a
> > rough estimate and the requirement varies based on content. Consider
> > it a guideline for 'an average DVD' as your source.
>
> Woops, that's what I meant, yes! Bit per pixel is a pretty rough
> estimate as not only the quality you'll get depends on the source (if
> it compresses well or not) but also on video resolution, i.e. lower
> resolution need a respectively bigger bpp to look good than higher
> resolution videos.
> Therefore, once you'd have read some video encoding guides, you should
> just use bpp as a starting point to run a compression test, and then
> adjust the bitrate accordingly.
>
> Guillaume
> --
> Life is pleasant. Death is peaceful. It's the transition that's
> troublesome.
>    Isaac Asimov (1920 - 1992)
>
> MPlayer's doc is offline. Find some fresh one here:
> http://tuxrip.free.fr//MPlayer-DOCS-HTML/en/
> http://tuxrip.free.fr//MPlayer-DOCS-HTML/fr/
>
> --
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>
>
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