XviD filesize prediction 100.000...0% acurate - how is it possible?

[Vanos_b]

I've been trying uManiacs' version (22.02) of XviD on a 10000 frames sample from Wild Wild West (just to see the resulting filesize so I could calculate aproximately the size I should enter for the full movie - I'm always using internal 2 pass). So I've done the first pass (no luma) and then set the second pass to 40,000 KB (that would be 100 KB/s). Resulting filesizes:
1. no luma, no sqf 40,960,000 bytes.
2. luma, no sqf 40,960,000 bytes.
3. luma, sqf 40,960,000 bytes.
4. no luma, sqf 40,960,000 bytes.
How is it possible? I mean it could produce a file acurate within a few KBytes but how can it produce a frame acurate within 1 byte (for the last frame it should in this case). BTW this means that XviD takes into consideration AVI header an indexes, right?

[-h]

Heh beats me how that worked out so well. The code does take frame overhead into account, but the deviation should still be around 40 KB or so, just by the nature of the overflow mechanism.

Internal 2-pass encodes will improve, probably as of tomorrow's builds, with a number of improvements made by Foxer. But, well, you know me :)

-h