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Old 24th April 2007, 15:26   #26  |  Link
plugh
A hollow voice says
 
Join Date: Sep 2006
Posts: 269
Quote:
Originally Posted by Dark Shikari View Post
Wait, xvid doesn't use floating point?
I can't comment in general, but I don't see any in that module at least. I do know there are floats in plugin_2pass2, but that wouldn't impact this.

I remembered I had a VMware virtual machine with W2K and a gcc setup on it (Msys 1.0.10, MinGW 4.1.0, gcc 3.4.4). Added nasm, installed xvid 1.1.2 sources, tried doing a build - success! So now I can poke at the gcc built version and see what it reveals about that module.

FWIW, the canned xvid+gcc build procedure uses the following gcc flags:
-Wall -O2 -fstrength-reduce -finline-functions -freduce-all-givs -ffast-math -fomit-frame-pointer

(note the 'fast-math' referred to earlier)

Guess I need to read up on them...

re-EDIT: Just did a quick one shot encode comparison between gcc build with/without fast-math flag --> one B frame is slightly differant in the .pass files. However, the gcc build *with* fast-math and msvc are in agreement on that particular frame.

Last edited by plugh; 24th April 2007 at 17:16.
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