Not sure if this is the place to ask....but

Amo-Chan · Post by **Amo-Chan** » Mon May 21, 2007 3:57 am

For some reason my vdub won't convert anything to an xvid. I needed to crop my video since I used both full screen and wide screen anime, but after I crop and go to compress I get an error message. It says it could be corrupt data, but it compressed just fine as an xvid(two passes), before I cropped it. Any suggestions?

Willen · Post by **Willen** » Mon May 21, 2007 5:20 am

It's probably due the video being in an improper resolution after cropping.

Generally, you can get away with the video just having pixel dimensions with even numbers. But it's recommended to use multiples of 16 (mod16) for the best compression. Using multiples of 8 (mod8) is acceptable, and for certain codecs, as good as using mod16.

Usually, if you are cropping video you'll have to do some resizing (and possibly adding borders) to get to an acceptable resolution.

Here are some typical resolutions:
For 4:3 videos:
640 x 480
512 x 384
480 x 360 (4:3, but not mod16)
480 x 352 (not exactly 4:3, but mod 16)
384 x 288
320 x 240

For 16:9 videos:
1920 x 1088 (not exactly 16:9, but mod16)
1920 x 1080 (16:9, but not mod16)
1280 x 720
1024 x 576
848 x 480 (not exactly 16:9, but mod16)
768 x 432
720 x 400 (not exactly 16:9, but mod16)
704 x 396 (16:9, but not mod16)
640 x 360 (16:9, but not mod16)
640 x 352 (not exactly 16:9, but mod16)
512 x 288
480 x 272 (not exactly 16:9, but mod16)

As long as you follow the guidelines, you can resize to any resolution (within reason). But remember, higher resolutions mean higher file sizes.

Willen · Post by **Willen** » Mon May 21, 2007 5:48 am

I should also add the special case of 720 x 480.

If you are using DVD footage, most likely it will be at that resolution. You can keep your video all through production at 720 x 480 and make your final export at that resolution also. But there are certain caveats.

1. Since 720 x 480 isn't 16:9 or 4:3, you'll have to set an aspect ratio (AR) flag to have your player software recognize it and properly resize it on playback.
2. Encoding at 720 x 480 for 4:3 sources is a waste of bits, since if properly resized on playback the video will end up at 640 x 480 resolution.
3. Not all video container formats support aspect ratio flags properly. MPG, MP4, MKV, and MOV support aspect ratio flags, but AVI will not.
4. Your playback software will probably need to be set correctly to display the proper aspect ratio on playback.

That being said, encoding at 720 x 480 for 16:9 video (especially for DVD-sourced material) can save a bunch on filesizes. Compared to 848 x 480, you are encoding 15% less pixels if you use 720 x 480.

Amo-Chan · Post by **Amo-Chan** » Mon May 21, 2007 5:39 pm

Ok, after resizing it's all good...well, all the same size anyway. But now some of the footage is really grainy. Not horrid grainy (I've seen worse), but still grainy.