Once cropped what do you resize it to?

[lingoguysw5]

I don't know much about lengths and widths and I have an avi movie which I have finally cropped with virtualdub and now need to resize it so it doesn't look too square and uses up most of the screen. The file info before was reading 720x240 which I thought was for video but anyway. It's for avi cd. Is there some sort of spreadsheet which would help me what to resize it to? Thanks

[daamon]

Hi lingoguysw5,

I'm not sure what you mean by "avi cd", but if you look under the "What Is" headings (top left of the page), hopefully that'll have the info you want.

[lingoguysw5]

I just wanted to know how to resize the avi video clip to a reasonable size and stick it on a cd to view through divx player. I have clicked on resize in the virtualdub filter and I don't know what size now with the subtitles clipped is the correct width and length to select. I was hoping you could tell me.

[daamon]

Hi lingoguysw5,

Ah, I see.

OK, use something like AVICodec to get the resolution of the original (pre-cropped) AVI - assuming you still have it of course (always a good practice).

Failing that, get the resolution of the cropped AVI as an approximation.

As a guide, I'd say you want the aspect ratio similar to what the original was. e.g. 640x480 which is a 4:3 ratio based on 160 pixels: 4x160 : 3x160.

Basically, try to avoid going bigger than the original actual resolution as you'll just get a "blocky" picture, and aim for a rough aspect ratio as per the original based on the above.

Experiment and see what looks good and right to you.

[lingoguysw5]

The original size was 720x480 uncropped and now I have cropped it what size should I put in? Can u only put in a special combination of numbers? Are there fixed sized in which you can choose from? The reason why I'm asking this is so I know if that's the case what sizes to play about with until I get one which is satisfactory with the subtitles cropped.

[daamon]

OK. 720x480 is an aspect ratio of 3:2.

As long as you've not cropped too much, you might get away with stretching the resolution back to 720x480 and not making the picture look too weird - try it and see how it looks.

If you don't like it, find out the new resolution (I'm guessing it'll be 720 x XXX). Multiply the XXX by 1.5 (because the original was 3:2 and 3 divided by 2 = 1.5) to get your new horizontal size.

So, if the new size is 720 x 400, you'll want to resize to 600 x 400 thus keeping the 3:2 ratio meaning the picture doesn't look weird (too strecthed in one direction).

This will mean that you keep the ratio at 3:2. I believe (not an expert on this) that the TV may then stretch the picture to fit the screen.

Again, try it and see. All you can waste is a bit of time. Use a CD-RW and you won't even have a coaster...

[junkmalle]

Divx AVI files must be a multiple of 4. Xvid can be any size. I'm not sure what is right for your Divx player (they handle AVI files differently) but I would resize to 640x240.

You shouldn't do this as two conversions though, you should do it all at once. Start with your original 720x480, use the Resize filter in VirtualDub with a crop. Ie, crop to 720x240 and resize to 640x240 in one step.

[thecoalman]

Not sure how a Divx player handles video but the ratios for a DVD compliant mpeg are determined by an attribute not the actual size of the video. For example you can have 720x480 in either 4:3(normal TV) or 16:9(widescreen). The DVD player will either play full screen for 4:3 or letterbox it for widescreen.

If and only if a Divx player handles video in the same way selecting a resolution won't fix the ratio (e.g. your video will be elongated vertically). In this case specifying it as a 16:9 will give you a better aspect ratio if you cropped a signifigant portion off the bottom and/or top of the video. If it was just a little you cropped selecting 4:3 might work better. If it's somewhere in the middle and neither has a correct aspect ratio I would suggest overlaying the cropped video on a new video with the same resolution of the uncropped one which will create a artificial letterbox which will work well for displaying on a 4:3 TV.

If a Divx player will display a video according to it's resolution examine the properties of your original video. Subtract the amount that you cropped from the heigth and pick a resolution that matches this the closest.

[junkmalle]

Standard AVI headers have no aspect ratio information so there's no reliable way for an AVI file to specify image or pixel aspect ratio.

Most Divx DVD players assume 1:1 pixel aspect ratio except for certain frame sizes. For example, my Liteon 2002, when it finds a 480x480 file, assumes it was originally an SVCD and stretches the width to get a final 4:3 image aspect ratio. But if if gets a file at 512x228 it will assume a 1:1 pixel aspect ratio and scale the image both horizontally and vertically, leaving you with a letterboxed image.

[lingoguysw5]

I am not looking to make a dvd out of my movie but just to leave it in the same (avi) format in which I downloaded it. That's why I don't understand why the file info in virtualdub says the size is 720x480 which I believe is designed for DVD isn't it?

[junkmalle]

AVI files can be almost any dimensions. Someone probably just recorded a widescreen movie and converted to AVI including the black borders. You can't convert it to fullscreen without losing part of the picture or distorting the image.