> >> Yes, it does. Of course, FireWire is more reliable and works better. > > > > Does Firewire retransmit if data gets corrupted on the wire? > > Hmm, I assume it is up to the applications involved -- it is a memory > mapped interface. At the very least it can run IP over FW and not > worry about it.
I don't think my camcorder is running IP. > >> I think that we should not worry too much about FireWire just yet. > > > > Yes, our big worry is decoding the video. > > 1394c supports autonegotiation of Ethernet or FireWire and runs on CAT5. Interesting. Since you can run IP over 1394, someone could make a 1394c hub/switch type box that you could plug both 1394 and Ethernet devices into. Probably wouldn't be hard to add USB ports as well. > >> so we are probably going to pay around $50- to get the > >> processing from an FPGA to implement 720p without a DSP. > > > > I was under the impression that FPGAs were hundreds if not thousands > > of dollars? And yet $50 worth of FPGA can decode 720p video? Is this > > H.264? I presume we also need to decode 1080i which would bump the > > requirements up a bit. > > Yes _good_ FPGAs are thousands of dollars ;-) "Good" meaning large and fast, or something else? > There is a large (mobile phone/PDA/etc) market for lower end FPGAs that > provide a processor bus for ARM and StrongARM CPUs, so they have gone > really far down in price. I was under the impression that FPGAs were used for low volume and development stuff. Things with the volume of mobile phone/PDA/etc would support making a custom chip. > Yes, decoding 1080i would require more processing power. The real > difference > is that 1080p has 129600 4x4 Macroblocks/sec, where as 720p only has > 57600. > I am still trying to figure out if we can half that number for 1080i, > which means that > it should easily be doable, or if MB bandwidth is the same for 1080i > and 1080p (if > it was, there would be less 1080i and more 1080p support, so I have a > feeling it is > not, but I am not sure). MB bandwidth? MB = macroblocks? Megabytes? Mercedes Benz? :-) ATSC uses 1080i rather than 1080p because they couldn't quite squeeze 1080p into the 19.something Mbps available. I wonder if 1080p/24 would have fit, that would have been a better match for most 1080 material. > > Could the OGD board be used to test the decoder? > > Yes. It will have an S4000 on it, much more than we need. We could > either try to > make the design entirely in the FPGA (better idea) or use the IDC > expansion bus > for the DSP (we should probably only do this once we are sure a design > will not > fit in the 1000, 1500, 1200E, or 1600E, since it would really reduce > our BOM cost > to only have the FPGA). It is not obvious to me why OGD needs a large FPGA but we can get by with a small one. Other than having two heads, what is OGD doing that we don't need to? > What sort of outputs should we have? > composite/component/HDMI/DVI/S-PDIF/? Have you read the "1st draft of Ethernet Video box requirements" I posted in May? Should be one of the first articles in the archives. There is also a "List of chips that might be useful for decoding video." posting, but it is sadly out of date. > The 6446 is designed for transcoding, so it has a resizer, etc, but I > think > you are right -- the 6443 should be fine. The 6443 doesn't have a scaler? Ouch. > > Do we have any idea how many of these we could sell? > > The Turbo.264, a Mac H.264 encode hardware accelerator the size of a > USB Flash drive > (with USB), supports up to 800x600 resolution out and costs $99. If > ours costs in the same > range (assuming we don't need the DSP, we might be able to charge such > a low amount), > supports encode/decode of 1080p, and can run Linux/custom FPGA and DSP > apps, I think > that we can get a lot of sales. Add in the built in TV out and > networking (along with the USB > we get for free with the 644*), and we should be able to sell at least > as many as that Turbo. > Remember, we should be able to support Linux, Windows, and Mac OS X, > which should > increase our sales. The box would be closer to the Apple TV's function, hopefully lower in price. Except without some of the stupid limitations. Apple TV only does 720p out, no 1080. I still can't figure out how Apple dropped the ball so badly, unless they plan to come out with a version 2 later. We will not have the Apple brand name, or a big advertising budget. We do have the Internet. If we can build a good box for a low price, word will spread and it should sell. The volume question is mostly due to chips having significant volume discounts. _______________________________________________ Open-hardware-ethervideo mailing list [email protected] http://lists.duskglow.com/mailman/listinfo/open-hardware-ethervideo
