mpg 352x288 to DVDA

robycos wrote on 9/9/2003, 5:13 AM
Hi all,

I would like to make a DVD by using some previously acquired movies. The resolution of the mpeg streams is 352x288 (progressive). I render them with vegas with the DVD-A PAL template and then I put them on the DVD with DVDA. The problem is that when I watch the DVD if the camera is stedy or it moves bottom-up (top-down) the movie is ok, but if the camera moves right -left of left-right the quality is very low. I guess is a problem related to interlaced mode but I don't know how to solve it!
any solution? than ks

roberto

Comments

farss wrote on 9/9/2003, 7:47 AM
I would suggest first render it our as standard PAL AVI from VV and see how that looks. If it looks bad then its not going to get any better when you encode to mpeg-2. Render it out as standard PAL 50i to get an idea. You may however get better results going to 24p mpeg-2 although going from progressive to interlace should be OK.

I've been doing a similar thing from WMV at about that res but the source was designed for streaming in the first place.
robycos wrote on 9/9/2003, 10:46 AM
what do you mean by 50i? is the same as 25fps interlaced? and why should I use 24p? this mean 24frame per second I think, and PAL system works at 25.

the original mpeg was of ggod quality (not excellent, but it was a good SVCD I did some tim ago).
Furthermore, if I watch on the PC the interlaced mpeg created by VV (with the preview of DVDA fpr instance) it looks good (at least I think so, it was late night when I did it!!! but I will watch it more carefully so that I can be sure of that).
But the strange thing is the following:

-usually when I preview a prerendered mpeg movie in DVDA, during horizontal movements of the camera I can see misaligned horizontal lines... I think that simply the interlaced movie is shown in a progressive way and so field A and field B are shown together instead of beeing shown one after the other (do you know if there is a way to avoid this, it is not so important, but....)

-instead when I preview the interlaced mpeg created by VV starting from the mpeg352x288 progressive clip
I can't see this behaviour!

I hope there is something clear in what I wrote!!! ;)
robycos wrote on 9/10/2003, 2:30 AM
I checked carefully the rerender mpeg file on the DVDA preview and I realized.. it is not so good:
as I said i can not see the horizontal mis-aligned lines due to interlacing (?) but the worst thing is that the images are deformed. When horizontal movements occur vertical lines are not straight but deformed like 's'. And the "snake" moves... This effect is not very evident in the preview but becomes very annoying on the TV.

I checked VV project settings and I found out 352x288 progressive and (maybe I am not sure) good quality rendering instead of best quality.

I changed these settings to 720x576 best quality and the problem disappeared.

As soon as I can I would like to check whether the problem is the resolution or the rendering quality but anyway this makes me quite confused:

- i thought that the quality was just related to the reduction of the artifacts that mpeg encoding introduces (like blocks and rings for example)
- how does the resolution can influence this? also because the final render was 720x576.. so does the resolution in the project settings really make a difference?

in what am I wrong?