VirtualDubMod streches mpeg from SVCD (extracted by VCDGear)

[Venom_IL]

After extracting the mpg from a bin/cue svcd using vcdgear, media player shows the right resolution when i play the mpg, yet when i open the mpg with vdubmod the picture is streched (vertically), and its not just the preview because after i encode it, the result is streched as well.

any suggestions ?

10x..

edit - using the resize filter (setting it to 720x540), i was able to remedy the problem, but resize reduces quality right? isnt there a way to make Vdubmod read the darned file right the first place? (like media player does, that is in wide screen, in the proper res)

[ronnylov]

SVCD resolution is 480x480 NTSC or 480x576 PAL
Depending on what mpeg2 encoder you use, mediaplayer might play it with corrcet aspect ratio by stretching it to 720x480 or 720x576.

So I don't think Virtualdubmod is stretching your video, I think mediaplayer does. What happens if you play your SVCD using a standalone player or a software DVD player like WinDVD or PowerDVD? I guess it will be correct aspect ratio.

To what format are you encoding? If you are encoding to avi to be played back on PC then you should have 1:1 aspect ratio and yes, it requires resizing.

Have you read the format conversion guides?
You can use Gordian Knot to get correct resizing to divX.
Use FitCD if you resize to VCD or DVD.

[Venom_IL]

thanks for your response

I am converting to VCD format, for the sole purpose of adding permanent subtitles. from the suggestions you gave me, I understand that what im doing right now (resizing to 720X540 - the same ratio Media player uses) is OK. the result has the desired aspect ratio, i was just wondering if i could do that without resize

if i play the SVCD on a standalone player then the aspect ratio is perfect

and that's what still doesnt make sense to me - if the _original_ SVCD mpg has the correct aspect ratio, then why when i open the file in VdubMod the picture appears streched ? what makes you say media player streches the file when media player plays it exactly like a standalone does? or does the standalone strech the mpeg as well? bahh this is all too confusing

i read some guides, yes , but i still dont understand completely whats going on with resolutions sometimes

[ronnylov]

The standalone player does also stretch it so it will look good on the TV. There is a flag in the mpg file that say "the aspect ratio during playback should be stretched to 4:3". The flag may also say "16:9" if it's on a widescreen DVD.

But virtualdubmod displays everything with 1:1 aspect ratio. Virtualdubmod is mainly aimed for avi creation to be played on computer and it's normally 1:1 with no stretching.

Mediaplayer need an external software mpeg2 decoder that comes with a software DVD player. This decoder may read this flag before sending it to media player but it may not. It depends if the DVD software does the stretching after decoding or within the decoder. So you should watch mpg on the computer with a DVD player software to be sure to get correct aspect ratio (if the file is encoded correctly of course).

By the way VCD in PAL format is 352x288 and in NTSC it is 352x240 pixels. This is not exactly 4:3 pixel wise either. So VCD is also stretched during playback but it's not as obvious as SVCD. If you encode with TMPGEnc you can set source and destination aspect ratios and everything will be fine if it's set up correctly. Both SVCD and VCD are meant for 4:3 TV aspect ratio so this is what you should set. The player will stretch the picture to fill the screen because the aspect ratio flag tells it to do this.

[Venom_IL]

thanks for your explanations, i still dont understand 100% (havent read enough faqs/guides) but there's only 1 important thing the way i see it - the movie has to be streched anyway, so what im doing is OK - because the final result is as it should be

Im just resizing to 720x540 through vdubmod, frameserving to tmpgenc and using full screen (keep aspect ratio) in the tmpg preferences

I dont have to (/want too) understand aspect ratios too well - it works well now and i let tmpgenc do the resizing so for me, the matter is resolved :D

thanks again :cool: