On Sat, 28 October 2000, Justin Schoeman wrote: > > I want to do distribution-quality video capture with my bt878 or Zoran 36120 (which I can't get to work at the moment), and then put that on a VCD format media. Am I asking too much to get NTSC-spec MPEG1 from this/these hardware card/s? > > The Zoran should be easy? Although I seem to rmember it only being > capable of compressed capture. I'm not clear on the specifics, but XawTV won't even work with the Zoran 36120 driver in -test9, and Pauline's drivers won't compile agianst late -test? kernels. It's ugly. From what I've been able to gather, the Zoran would be able to get the frames at full size in full speed more reliably, but I may have misinterpreted my data. The 36120, by the way, does not do any compression on it's own. You have to have another Zoran chip that is made for mjpeg on the card, which I do not. > Anyway, I can't guarantee this, but my latest measurements show that it > should be possible to record at full rate and full size from a Bt8x8 > based card. The problem is that you will probably start getting line > drops. I see; that's the clearest anyone has ever been able to explain it to me. > So, you will just have to try and see! Make sure your harddrives can > sustain > 25MB/s (a little overhead for seeks, etc.), install the rawio > patches for the kernel, write a capture driver that can use rawio to > capture to a raw partition on the HDD without too much kernel overhead, > get a motherboard with really low latency PCI arbitration, and hope... Wow. That's a bit complicated, now, isn't it? :) You couldn't use rawio on a software raid0, though, could you? > Sorry, in the end I haven't really answered your question. In theory it > is definitely possible, but I have a horrible suspision that the > arbitration latency on the PCI bus is going to keep theory from > becomming practice... This is a bit off topic, but I've seen the Asus K7V (VIA KT133) consistently score perfect 500MB/sec of memory-to-cpu bandwidth. Can anyone vouch for the PCI latency with this chipset? -- -=|JP|=- "You must only realize that there is no spoon."
