On 1/30/06, Dan Seddon <[EMAIL PROTECTED]> wrote: > Hi Jerry > > Video comes to about 30 Mbytes per second - which would be about 240 > Mbits per second, as you're almost a multiple of 3 bigger I'm guessing > you assumed 24bits per colour channel? Where it is actually 8bits per > colour channel (PAL is 3*720*576*25 bytes). This ought to be well inside > the speed of PCI - if you think about it, uncompressed PVRs have existed > for some years now and the harddrives on these use the PCI bus. So, it's > unlikely you've exceeded the bandwidth. 60 frame/sec is interlaced NTSC > (720p is progressive) - I wouldn't think this would increase the > bandwidth unless you were doing something like bob deinterlace on your > CPU (I'm guessing here), as each frame should have half the number of > lines. I don't know about XvMC - I don't know how compressed the data is > by the time it gets to the card - you'd hope it was a little compressed > though! > > Ta > > Dan
Hi Dan, PVRs have existed for a while, but not HD-resolution PVRs - they're pretty recent. If X is in a 24-bit depth mode, then I don't see where my numbers are off - 24 (bit depth) * 1280 * 720 (screen res) * 30 (fps) = 630+ Mbits/sec. XvMC is a mystery to me - compressed data must be sent to the card for decompression, but I don't know how big that factor is, or whether it has to travel back to the CPU again before being sent for display. Anyway, thanks for your comments. -Jerry _______________________________________________ mythtv-users mailing list [email protected] http://mythtv.org/cgi-bin/mailman/listinfo/mythtv-users
