Input is still being decoded by 32 bit apps, but for avs2yuv you need to pass it some extra parameters, also pipebuf.exe can assist on setting a larger buffer for more speed.
An example using this
tool.
Code:
Source: E:\test.avs
Output: E:\test.mkv
Params: --crf 26
Analayzing source file:
E:\test.avs: 1280x720, 2500000/104271 fps, 1275 frames
Resolution: 1280 x 720
Frame No. : 1275
Frame Rate: 2500000/104271
x264 0.66.1101M b69548a
built on Feb 5 2009, gcc: 4.4.0 20081231 (experimental)
Commandline for x264:
"F:\TOOLS\x264 x64 Launcher\pipebuf.exe" "F:\TOOLS\x264 x64 Launcher\avs2yuv.exe" E:\test.avs -raw - : "F:\TOOLS\x264 x64 Launcher\x264_x64.exe" --crf 26 --threads auto --progress --frames 1275 --fps 2500000/104271 --output E:\test.mkv - 1280x720 : 4
The weird --fps is needed for accurate 25 and 29.97 output.
23.976 won't be accurate until x264 is fixed. Common --fps like 29.97, 29.97030, 29.97/10001 won't work.