Small question about bitrates

[drdread]

When I use VdubMOD to compress a file into Xvid, I see a status window, and one of the boxes says "Average Bitrate". What exactly is that? Is there a way you can change it, and if you can, why would you do that?

I read the page located at http://www.animemusicvideos.org/guides/avtech/xvid.html but I don't quite understand. Is it just telling you the final size of the file or what?

[drdread]

Is there an edit button or anything? I can't seem to find it if there is one.

Anyway, I'm also confused about the First Pass and Second Pass stuff. How do you know to use which one? I am using First Pass and my file seems to work the way I want it to, but I don't even know what it does. I just configured Xvid the way it's shown on http://www.animemusicvideos.org/guides/avtech/xvid.html .

[Zaphod_Beeblebrox]

when exactly is this when you're compressing? is it when you're configuring XviD or is it when XviD is actually compressing your video?

[Scintilla]

When I use VdubMOD to compress a file into Xvid, I see a status window, and one of the boxes says "Average Bitrate". What exactly is that? Is there a way you can change it, and if you can, why would you do that?

I read the page located at http://www.animemusicvideos.org/guides/avtech/xvid.html but I don't quite understand. Is it just telling you the final size of the file or what?

Average bitrate = average of how many bits are being used in any given time interval. Usually measured in kilobits per second.

Higher bitrate = bigger files and (up to a point) higher quality.
Lower bitrate = smaller files and lower quality.

You would want to increase the bitrate if you're seeing too many artifacts and blocks for your liking, or decrease it if you need a smaller file.

(Oftentimes, a good idea for getting better visual quality with smaller filesizes is to reduce the resolution.)

Is there an edit button or anything? I can't seem to find it if there is one.

No. Only on the AMV Contests, Anime Conventions, and Heads Up! boards.

Anyway, I'm also confused about the First Pass and Second Pass stuff. How do you know to use which one? I am using First Pass and my file seems to work the way I want it to, but I don't even know what it does. I just configured Xvid the way it's shown on http://www.animemusicvideos.org/guides/avtech/xvid.html .

In the two-pass method of encoding, the first pass is used to analyze the video to be encoded and generate a log file, which is then referred to in the second pass to improve the distribution of bits.

Don't ever choose "2-pass (second pass)" unless you've just done a "2-pass (first pass)" <i>on the same video</i>.

If you've configured the XviD encoder options the way the guide page tells you to, then your 1st pass should have been encoded with constant quantizer 2 (and 4 for B-frames, if you used any), which produces the highest visual quality you can get "without stupidly big files".
If you find that the 1st-pass file is too big, you can run a second pass and specify a desired filesize/bitrate.