afaik you can't DMA into chipram?
Why do you think that? Lots of zorro2 cards can DMA into chip ram, it's not ideal but it works.
Video CD are 1.44 Mbps. AGA has enough bandwidth, not so sure about ECS.
That's 1.44Mbps of compressed MPEG stream. The decoded stream is ~61Mbits/s for NTSC. Mind you that's 24-bit video which AGA can't even display. If you cut it down by a third by having some sort of hardware HAM8 encoder in your card, you could theoretically stream a VCD as HAM8 onto an AGA system, while severely limiting any other chip memory activity done by the CPU. The question is, why?
Similar issues occur when you're trying to use AGA to display full-screen games, or output from an emulator, etc. The bandwidth of chip memory is such that a low-res game can do 8-bit 50/60fps using almost all of chip mem's bandwidth not used by Lisa/etc. (and if CPU driven this means the CPU is eaten by wait states in the process, but you were talking about DMA). Since VCD is half that, it basically means that you'd be eating up half of the available chip cycles exposed to the CPU bus just by decoding the video. Doable, but again, why?
