DivX 5 filesize issue

[the oil]

hi,

there is something about divx 5 i just can't figure out.
i am using divx 5.0.2 pro and DVDx.

i tried to encode a 2 hour movie and therefore calculated the video bitrate (given 128 kbit/s for audio left me with around 1500 kbit/s for video (2 cd's) - that's at least what the math says).
when i was using this bitrate i got 2 files of the size of about 550 MB instead of 700 MB. so i thought the movie might be "maxed out" but tried again to encode it quality based at 100%. then i got files of the size of about 800 MB.

so i'm a little confused about this. does the simple math (bitrates * 8 * movie length) not work with divx 5 ? and if not - why and does someone know a good bitrate calculator that takes care of that problem ?

thanks a lot in advance !

[N_F]

The simple calculations do applay to DivX 5. Are you sure you didn't miscalculate somewhere? How long is the movie?

You did of course use the same resolution etc when you tried quality based 100%... ?

[jggimi]

Though this may sound like a broken record; why not try GKnot? It is a bitrate calculator -- and encoding suite -- that offers compressibility tests that can produce comfortably accurate file sizes with 5.02.

[the oil]

i've been using the same algorithm with DivX 4 and it worked perfectly - so i think the math is correct.

yes the resolution for both encodings was the same.

can i use gknot only to calculate the bitrate - i kinda like DVDx...

[jggimi]

yes, you can, if you use dvd2avi project files. Just spend your time on the bitrate and resolution tabs.

[snooty]

It's weird, but I get this problem even WITH GKnot & Divx 5. Files are always far smaller than the calculations tell me. Quality's still great though.

Paul