On Thu, Aug 10, 2000 at 05:03:06PM +0100, Andrew.Stevens@xxxxxxxxxxxxxxx wrote: > > > > The Iomega BUZ seem kinda cool, but they don't seem to > > > sell it anymore: > > > > The MAC version is the PC version, with MAC software (both have PCI > > bus).... > > > > People are working on versions with the Matrox Video card that has the > > Zoran MJPEG chip on it also... > > The Miro DC10+ now also has drivers... however if you can afford itwait > for the Matrox drivers to appear. It is a *pain* not having a tuner > on-card. I lost count of the number of times some minor househould > glitch lost or disturbed a capture. All it takes is a cat sitting on a > remote (or a dumb > cat-owner pressing the wrong remote) and... bye bye "Lexx" and hello > "Sports quiz gameshow" ;-( > > My experience in setting a Digital VCR rig up has been that it is very > easy to underestimate the "minor logistical issues" and level of > reliability required to make the whole thing work adequately. Capturing > a 90+ minute movie or even a 50 minute series episode to disk exposes > all kinds of minor warts you'd never notice otherwise. > > Unhappy experiences (solved) > > - Forget VIA VPx motherboards. The PCI implementation is too flaky / > too mismatched to the Zoran. Here a frame gone there a frame gone. The > ATA UDMA drivers for VIA are also not really up to the grade either... > > - Get a good mature sound-card with mature drivers. Much gnashing of > teeth until I spent a few $ on an OEM AWE64. On-motherboard sound is > often (audibly) rotten... > > - Dedicate a machine. Drivers and/or hardware are not up to handling a > general-purpose load *and* a video stream capture. Even with liberal > use of process priority... Any kind of X windows activity seems > particularly poisonous. Whether thats because multiple process can > suddenly become runnable, a paging load, or the screen driver spending > significant time with interrupts locked I don't know. > > Again, perhaps Alan or other folk with kernel know-how might be able to > shed light on this phenomenon. > > Unhappy experiences (not fully solved) > > - Put bluntly: ext2 is not good for video capture (I'll bet the TIVO > guys are writing direct to disk not via an FS). Ext2 has an evil habit > of wandering off to do surges of head-rattling house-keeping for longish > periods of time when a big file is closed. Presumably it is updating its > block trees. Net result: a 0.5M/sec video stream cannot always be > streamed without loss on a 20M/sec hard-disk because usually you have > to split over multiple files. Once > 2G I/O stuff hits the maintstream > and/or the new FS come on line this should become a non-issue but in the > meantime it is a pain.... > I haven't had any problems with mp1e and my bt848 on a relatively old 7200 rpm Micropolis disk connected to a 2940 narrow SCSI controller. The files stay fairly small, so I've never had to go over 2gB. It seems to be doing some sort of double-buffering or something, since it splits up into four threads during the compression process. Even when I use the machine it tends to be OK, unless I do something to saturate the bus like a 3d rendering benchmark. I'm putting together a seperate machine to run two bt848 cards in order to record multiple shows at the same time. I'm also going to be trying my luck with one of those cheapo 40gB IDE disks. I'll let you all know how it goes. -- Brian Ristuccia brian@xxxxxxxxxxxxx bristucc@xxxxxxxxxx
