YASM Active

Thanks to Loren Merritt for restructuring FFmpeg’s build system to use YASM and for submitting and relicensing a number of ASM optimizations compilable with YASM. The idea is that if you have YASM installed (x86_32 or x86_64), FFmpeg’s configure script will notice it and automatically compile in the new optimizations. I just installed the assembler on both the x86_32 and x86_64 FATE build machines.

Hope it works, and that it’s faster than before. I look forward to assessing how it improves performance on certain H.264 conformance vectors, particularly monsters like MV1_BRCM_D. From the associated README file:

“Check that the decoder handles the worse case of prediction bandwidth. Prediction bandwidth is at maximum due to largest number of motion vectors (in 1/4 pel position) per macroblock pair (32 as defined in standard). Non-integer position motion vectors require using 6-tap filter always.”

I’m not sure what all of that means. I just know that it takes a long time to decode on the FATE machines.