[x264-devel] CPU required for real time x264 encode of 720P

[Andrew Robbie (Gmail)]

Dear list,

I need to do real time encoding of 720P video captured from Blackmagic  
Intensity/DeckLink cards:

http://www.blackmagic-design.com/products/decklink/

It is hard to get an idea of how much CPU is required to do this with  
x264. For example, if I have an Intel Xeon E5640 (Gulftown 4 cores,  
2.66GHz) or a Core i7-940 (Bloomfield 4 core, 2.67GHz) what frame rate  
can I expect for 1 core or 4 core?

According to the card manual the bitrate for uncompressed 720P is 141  
Mbytes/s in YUV, 211 Mbytes/s in RGB. I would like to keep latency of  
encoding below 100ms, willing to trade increased bitrate for faster  
encode. If anyone has suggested presets for this that would be great.

Also, I am pondering the AMD Magny Cours CPUs (6100 series). Does  
anyone have benchmarks for these 8/12 core systems? Not sure how well  
x264 will scale. The sites like AnandTech which have benchmarks have  
no detail as to the settings used which makes them a bit useless.

Thanks for any suggestions,

Andrew