[MPlayer-users] Scaling interlaced video for DVD playback

[D Richard Felker III]

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.

Rich