hey,
fpga s are "better" used for complementing dsps, so dont mix fpga and dsp.
yeah fpga can do what a dsp could. but let it do what its made for, asic
now a days u find even h.264 main profile implemented on fpga. but thats just a engine, the dsp along side utilizes the fpga to bring together processing power flexibly
most of the video products use fpga along it. here the fpga is used as video port (peripheral). most of the tms320c644x series or davinci have on chip video peripheral, and high end graphics accelerator
now if u're working on a processor which has no specific peripheral or accelerator (which u require). use the muscle power of fpgas to reduce the burden from dsps
this post is not intended to hurt someone who's already posted better answers. its just what i know and worked on.
please correct me if u find any blunders in this post
thanx
mon