FPGA or SSE2 ?

I've done a simplified JPEG (same principle but more specialized) encoder that only took b/w (but color is basically 3 times that + color space conversion and different resolution and in a FPGA, you can just duplicate the hw) and it took about 1500 LE in a basic Altera Cyclone and it runned at about 100Mhz, needing 2 clock / pixels. I didn't try to optimize it much since the first implementation met the constraint I needed. So if you duplicate the hw for the other color component, the figure would be 50Mpixels/s => 144 fps (0.007 sec par image).

So I'd say yes, you can easily beat the P4 for such a dedicated task. The problem as you stated is to get the data in and out. 50Mpixels par second at 24bits color is over the PCI peak rate (133Mbyte/s and it's never reached).

RLE is basically a counter with a barrel shifter. Huffman, a simple encoding/decoding table. Both can be done pretty efficiently.

Sylvain

Thanks a lot Sylvain - that's exactly the sort of comparison I needed :) I won't just be doing JPEG, but it's pretty typical of the sort of code so it's a good benchmark, and a speedup of almost 6x is well worth investigation :)

John

True for PCI 32/33, but don't forget about PCI 32/64, PCI-X and PCI-E. You'll only find PCI-X on server grade motherboards, but at 64/133MHz, you get a good GByte/s odd (not all of which you will get, but still fairly high). You can get PCI-E on newer motherboards as well, with theoretical bandwidths of 2.5Gbit per lane (312MByte/s per lane). I'm not too clear on what you can practically achieve with PCI-E - the technology is still fairly new to me. PCI-E is available on non-server grade motherboards too - I'm figuring that the possibility of using a standard PCI-* interface is probably easier than trying to integrate the device as closely as the northbridge :)

Jeremy

Actually the 2.5 Gb/s is with electrical bit rate which results by encoding using the 8b10 code so it is not available as data rate at all. The best logical bit rate is 2 Gb/s on top of which you put all the framing, packetization etc. so actual utilization is still lower than that.

Woops :) Shouldn't have missed that one.. Had it somehow in my head that it was a 3.125Gb/s raw bit rate.

Jeremy