Comp test and Divx 5 Enc by Jonny

[bjfacca]

I know there are a lot of threads about this topic, I did a search and read *a lot* of posts about doing compression tests and maybe it's because my english is not too good or I'm just stupid but I can't exactly figure out how to use Jonny's utility to get the file size I want, and I'm sure it's my problem not Divx 5 enc's ;)

Here is what I get in a comp test I did using the instructions found in the docs folder, the movie is "don't say a word", it's very dark:
Ok 117,68% 4,175,000 / 3,547,808

Please correct me if I'm wrong (I probably am):
117% this number indicates how much oversized (or in this case undersized) the file got comparing to the predicted file size

4,175,000 indicates the predicted file size

3,547,808 indicates the size of the file encoded in the test

Assuming that what I said is right, to calculate the file size I want I would have to make some other .avs files in gknot (like incresing resolution or something) until one of them gives me a good value?

Other thing is: I read posts sa saying, 40% to 70% is acceptable, over 80% will probably be undersized. How did you (or anyone) established these values? Why over 80% will be undersized?

I apologize for the stupid questions
Thanks for your patience

Bruno

[jonny]

Ok 117,68% 4,175,000 / 3,547,808


This values are TOO low for a real full movie (target and predicted size)
I think you have missed something... have you correctly insert the number of frames?



I'll respond to the other questions anyway...


117% this number indicates how much oversized (or in this case undersized) the file got comparing to the predicted file size


117% = 100 * target_size / predicted_size
In this case the bitrate used is too high, and the movie will be undersized.



Assuming that what I said is right, to calculate the file size I want I would have to make some other .avs files in gknot (like incresing resolution or something) until one of them gives me a good value?


Changing the resolution will change 2 things: the predicted size and the compressibility test value.
Yes, you must increase the resolution in order to lower the compressibility test value.



Other thing is: I read posts sa saying, 40% to 70% is acceptable, over 80% will probably be undersized. How did you (or anyone) established these values? Why over 80% will be undersized?


Testing.



Cheers
jonny

[bjfacca]

I only used a part of the movie for doing the test.

Thank you

Bruno