andy vt's tools & blog

Hi,

Assuming that in the following output from mencoder that 0 means no and 1 means yes, I believe there is a problem with how mencoder is recognising if a CPU is SSE/SSE2 capable.

MEncoder dev-SVN-rUNKNOWN-3.4.5 (C) 2000-2006 MPlayer Team
CPU: Intel(R) Core(TM)2 CPU         T7200  @ 2.00GHz (Family: 6, Model: 15, Stepping: 6)
CPUflags: Type: 6 MMX: 1 MMX2: 1 3DNow: 0 3DNow2: 0 SSE: 0 SSE2: 0
Compiled with runtime CPU detection.

I've run Dtb/Mencoder on a couple of PCs and am seeing this on both machines. One is a Mobile Core 2 Duo T7200, and the other is a Celeron D 330. Both these CPUs are compatible with SSE, SSE2 and SSE3, as the below links show.

http://www.cpu-world.com/CPUs/Core_2/Intel-Core%202%20Duo%20Mobile%20T7200%20LF80537GF0414M%20(BX80537T7200).html

http://www.cpu-world.com/CPUs/Celeron_D/Intel-Celeron%20D%20330%20-%20RK80546RE067256%20-%20NE80546RE067256%20(BX80546RE2667C).html

Now, if there is no optimisations using SSE or SSE2 when encoding to h.264 then I don't suppose it matters, but if those optimisations do exist, then they won't be getting used if the detection process isn't working.

I'm using Dtb 1.1.0.6 on XP with Mencoder as supplied in the Dtb installation to shrink DVR-MS to x.264.

OK, so I've realised that 1.1.0.6 doesn't come with the latest version of mencoder. I've downloaded the latest mencoder, but it's still not identifying SSE/SSE2:

MEncoder dev-SVN-rUNKNOWN-4.2.1-sjlj (C) 2000-2007 MPlayer Team
CPU: Intel(R) Core(TM)2 CPU         T7200  @ 2.00GHz (Family: 6, Model: 15, Stepping: 6)
CPUflags: Type: 6 MMX: 1 MMX2: 1 3DNow: 0 3DNow2: 0 SSE: 0 SSE2: 0
Compiled with runtime CPU detection.

You are correct that Mencoder won't auto detect SSE or SSE2 in Windows.  There are quite a few discussions going on with the developers right now on the benefits of SSE verses MMX.  However, the big benefit is with X264 encoding.  You will notice that with my version of Mencoder version 12 the X264 library is an external dll.  I did this so SSE and SSE2 could be auto detected in the dll and used with the X264 library.  If you look at the whole mencoder output you should see this:

CPUflags: Type: 6 MMX: 1 MMX2: 1 3DNow: 0 3DNow2: 0 SSE: 0 SSE2: 0
Compiled with runtime CPU detection.

The above two lines are the CPUflags for mencoder itself.  However, the line below is for the the X264 dll.

x264 [info]: using cpu capabilities: MMX MMXEXT SSE SSE2

Hope this helps clarify what is happening.