[MPlayer-users] Re: 1080i to 1080p mpeg2 or x264?

[Steven Adeff]

On 2/28/06, Loren Merritt <lorenm at u.washington.edu> wrote:
> On Tue, 28 Feb 2006, Steven Adeff wrote:
> > On 2/28/06, Loren Merritt <lorenm at u.washington.edu> wrote:
> >>
> >> At least in x264, it's more efficient to leave it at 1080 and let x264
> >> decide what to stuff in the bar, rather than force blackness. Any
> >> compliant h264 decoder will crop it off on playback.
> >> (of course, scaling/cropping to 1088 or 1072 also work)
> >
> > does x264 automatically make it 1088 then?
>
> yes.
>
> >>> Though I don't know if the processing time is worth the space trade
> >>> off to go to mpeg2 so right now this is more academic for me...
> >>
> >> Then try mpeg4.
> >
> > oops I mean to go to mpeg4, mpeg4 takes 5x the time to encode over
> > mpeg2 from my tests but only nets about 20% file size savings.
>
> Are you sure?
> In a quick test with no mpeg4-specific options, I got mpeg4 vs mpeg2 is
> 18% slower and 16% lower bitrate per psnr.
> mbd=2:trell:vmax_b_frames=1:subcmp=2:last_pred=2:vcodec=(mpeg4|mpeg2video)
> Of course you can make it really slow if you turn on everything, so
> just don't do that.
>
> --Loren Merritt

sorry, for mpeg4 x264, not straight mpeg4. x264 encodes take quite a
bit longer than mpeg2 and don't show that much of a space savings
using the more default commands.

What commands should I turn on is the question... I'm not well versed
in what the commands do which is why I'm trying to see if someone here
has done a lot of x264 encodes and has a good grasp on what to use.
I've found this type of information for doing xvid encodes so I'm
wondering if anyone has done any experimenting in optimizing x264
settings for HD streams or knows what the "settings" are for how h264
will be implemented for HD-DVD and such.

I understand its somewhat subjective as to whether the output is
"equal" to the input, but since I'm not really trying to optimize on
filesize I figure using an equivalent q of 2 for the encodes while
running pullup,softskip for 1080i content or decimate for 720p to
cutdown on the framerate should give me a decent filesize savings
along with having all my mpegs progressive.



--
Steve