Some AR value not saved in bitstream

[SamKook]

I've made a batch file to encode DVDs in avi/xvid. It is being cropped and resized to a mod16 resolution(for best compatibility with standalone players) and then I set the DAR to correct the cropping I made(for PC playback).

It worked perfectly well until I tried to set the DAR to 841x480 for a 848x480 video. The DAR was simply ignored and the video stayed at 848x480 so I was wondering why that is? Setting the same video to an AR I used for another one works perfectly fine so the problem really seem to be those values. I also tried to do it manually in case something was wrong with the batch file, but I arrived at the exact same results.

After a bit of messing around, I also found that setting it to 840x480 also doesn't work but 105x60 does and actually gives a result much closer to 841x480 when I check it with mediainfo.

I tried searching for what you can and can't set for the DAR but couldn't find anything that helped me.

I'm using Xvid-1.3.2-20110601 _Final Release_ from xvid.org and VirtualDub 1.9.11 build 32842/release

Also, on an unrelated note, if someone knows how to automatically set the DAR for xvid video in VirtualDub instead of making a different processing setting preset for each it would really be helpful.

[SeeMoreDigital]

I think reading the following topic may help you: MPEG4 Modifier v1.3.4 Released (http://forum.doom9.org/showthread.php?t=78050)


Cheers

[SamKook]

Other than the loss of the Writing library info and that it has to rewrite the whole thing(I can sometime have low disk space), this seem like a pretty good solution to automate the process.

MPEG4 Modifier can set the DAR(seems only the PAR is stored from what I'm reading, but the result and question is the same either way) properly if I feed it 841:480, but it gets transformed to 212:121 and virtualdub did the same with 105:60 so I was wondering how is that decided and why isn't 841:480 working if set via virtualdub if it's going to get round up somehow anyway?

I'm grateful for the solution(which I'll probably end up using), but I'd still like to figure out why it isn't working properly via virtualdub or if I could do the rounding up myself in my batch file to have better control over the result(not that it matters much for that tiny of a difference).