[MPlayer-users] Ripped DVD got wrong aspect ratio?

[Steffen Barszus]

On Friday 08 November 2002 17:27, Diego Zuccato wrote:
> [Automatic answer: RTFM (read DOCS, FAQ), also read DOCS/bugreports.html]
>
> Chris Phillips wrote:
> > > But TFM says just "-vop scale" without parameters... Is -1:-2 the
> > > default?
> >
> > TFM says:
> > scale[=w:h[:c[:p]]]
> >     Scales the image with the software scaler (slow) and performs a
> >     YUV<->RGB colorspace conversion (see -sws  option  too).   The
> >     value 0 is used for scaled (aspect) destination w/h.  (default:
> >     original w/h, destination  w/h  with  -zoom)  Optionaly  chroma
> >     skipping  (c from 0-3) and scaling parameters can be specified.
> >     (see the -sws option for details)
> >
> > so all this stupidly long drawn out and sidetracked thread was started
> > when you'd not even bothered to try an option you already knew about, and
> > is even called "scale"???
>
> I haven't access to that machine from here. And I read about scale only
> after encoding the movie. More, TFM cited it relative to VCDs, not DVDs.
> More again, WHY IN THE HELL should one think about using a scale option
> if NO SCALING is desired ???
> I followed the (IMO) most logical path: I want a 3-CD rip (for really
> hi-quality) of the DVD. I don't want to mess the video part too much,
> and the "native" resolution is good for me (if you scale to anything
> that's not an integer divisor of the source you lose more quality - then
> I keep the source resolution). So I use the minimum number of options,
> better if taken from someone that already used 'em.
>
> If ignoring aspect header when encoding from mpeg (but NOT when playing)
> is a feature, it's a really strange one. I'd call it bug if it wasn't
> (at least partially) documented...

No its not a bug, its totally normal. It is because avi is not able to store 
AR , so if we had a better container , we could forget all these stuff. 
What I did not understand is why you bother about scaling and loosing quality 
trough that and in the same time you try to recompress video. Recompressing 
mpeg2 -> mpeg4 will let you lose a lot of information (thats the reason you 
do it I guess), so it is not the question how to not losin information, more 
it is the question on how to loose them , so it is not noticable as much as 
you could. Downscaling is a good method for that, since it could be easily 
restored by upscaling without much quality loss. Compressionartefacts will 
suck a lot more. 

I think this thread is very informative, but I don't know if this is the right 
forum for it. If someone can give an advice for where doing such discussions 
I would love to do it there ;o)

Greets

Steffen