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View Full Version : x264 encoding with -march=amdfam10 and -march=core2


noee
22nd June 2009, 18:51
I have a K8 and I've been testing with two versions of x264.exe (from xvidvideo.ru), one with -march=amdfam10 and the other with -march=core2.

My source for testing is DVD SD material. The command line settings:

"C:\x264.exe" --crf 20 --threads auto --thread-input --no-psnr --progress --keyint 250 --bframes 5 --mixed-refs --trellis 1 --ref 4 --deblock -1,-1 --subme 6 --direct auto --vbv-bufsize 14000 --vbv-maxrate 25000 --me umh --merange 16 --no-ssim --weightb --b-adapt 2 --b-pyramid --partitions p8x8,b8x8,i8x8,i4x4 --8x8dct --aud --aq-strength 1.0 --psy-rd 1.0:0.0 --sar 1:1 --output "D:\Temp\test.h264" "D:\Temp\test.avs"

The final file is 20MB smaller using the K10 version vs. the Core2 version and the bitrate for the core2 version is ~950 vs ~750 for the K10 version.

I've read thru some of the patch descriptions, but most of it is over my head.

Why is there such a difference just based on the march build?

Dark Shikari
22nd June 2009, 19:03
If there is even a single bit difference with threads off and you can rule out Avisynth as the problem, x264 has been miscompiled.