[MPlayer-users] Scaling interlaced video for DVD playback

[D Richard Felker III]

On Mon, Nov 17, 2003 at 08:12:24AM +0100, Fabio Papa wrote:
> [Automatic answer: RTFM (read DOCS, FAQ), also read DOCS/bugreports.html]
> On Friday 14 November 2003 21:40, D Richard Felker III wrote:
> > [Automatic answer: RTFM (read DOCS, FAQ), also read DOCS/bugreports.html]
> >
> > On Fri, Nov 14, 2003 at 08:10:10AM +0100, Fabio Papa wrote:
> > > [Automatic answer: RTFM (read DOCS, FAQ), also read DOCS/bugreports.html]
> > > Hi list,
> > > it has been some days now that I'm trying to find the optimal way tho
> > > handle interlaced video I capture from a bt 8x8 card.
> > > I used to deinterlace contents, but I was never happy with the results.
> > > Then I got inspired from some of D Richard Felker III words and I started
> > > to find a way to scale my videos (which is a need for me) while retaining
> > > them interlaced. I finally come up with the idea that the most correct
> > > video filter chain is something like:
> > > -vf il=d:d,scale=xxx:yyy,il=i:i
> > > The resulting video is still interlaced, but with more thick lines, which
> > > I think is ok given the rescale operation.
> > > Now, if I convert this to mpeg1 with mencoder, and use it to master some
> > > test DVDs, I see the interlaced artifacts even on tv. It seems my dvd
> > > player or tv set is not displaying it properly.
> >
> > No, you made the video wrong. As far as DVD/[S]VCD is concerned, there
> > is no such thing as 352x240 (or 352x288) interlaced video. Even if it
> > were possible, it would look extremely bad. Either make full 480-line
> > (or 576-line for PAL) DVDs, or else deinterlace and make low-res ones.
> >
> > > How would one solve that? And, more in general, what's the correct
> > > procedure to handle such interlaced files for later TV only view?
> >
> > The correct way is to keep the full resolution. The only reason to
> > ever scale interlaced video is if you're going to be playing it
> > smaller. One good example is the effect news shows do, where they
> > scale down two tv pictures and put them in small 'windows' on the
> > screen.
> 
> Ok, understood. Now a new problem arise: how do I do a lossless capture from 
> my TV card at such resolution? ffv1 is much cpu consuming and huffyuv will 
> fill my HD up. Is there some other possibilities?

Try NuppelVideo's lossless mode, but it might also fill up your HD.
Another thing you could do is the correct interlaced scaling to reduce
resolution, then scaling it back up (again with correct interlaced
scaling) to master the DVD. But that might look bad. You could just do
horizontal scaling (e.g. capture at 480x576 or so, maybe even 352x576)
and then scale back for the dvd. Horizontal rescaling doesn't need any
special precautions for interlaced video.

Rich