On Feb 2, 2004, at 01:18 am, Gregg Eshelman wrote:
--- Mark Benson <[EMAIL PROTECTED]> wrote: <clip>840av. Dunno what the Media 100 is like for output so can't say for certain.
Media 100 native codec is apparently a type of JPEG with each frame compressed to anywhere from 10K to 150K for 640x480 NTSC. Frame sizes are slightly higher for PAL which has more lines.
That's MJPEG. Same as is used by most capture cards of that era. The 840av uses that and the Spigot Power AV accelerates the JPEG compression to allow it to mince more frames per second. Quality is quite good for old tech.
It seems to have hardware compression on the NuBus cards because it's capable of this same capture performance and realtime playback to the video output analog ports even on an 840AV.
The PowerAV uses the direct interface (essentially PDS for the onboard DSP/Video) behind the top slot to move data to the main board and only uses the NuBus as a low level command interface conduit. The result is however that the video capture can on;y be done with a monitor or TV attached to the onboard video.
The bottleneck is hard drive write speed. The manual says it needs at least 4.5 megabytes per second, which ought to be within the means of that 18.2gig SCA drive, but apparently not when necked down to narrow SCSI. :P
I can't record [EMAIL PROTECTED] on my 840av and it proports to be able to get 12MB/s over the SCSI bus. I think it's lying :-)
What'd really be neat is if I could find a RAID 0 disk driver that supports volumes larger than 4gig on NuBus PowerMacs. Apple RAID and SoftRAID run the version 1.5 68k code driver on the NuBus Macs, PPC or 68k CPU. But at least after being setup, the RAID 0 volumes can be Erased to HFS+, under OS 9.1 anyway. :) 9.1 also supports pretty large volumes and files larger than 2gig.
I've done this in 8.1 on my 840av before now (when I have a Silicon Express IV Wide-SCSI card) and it's hella fast and hella not bootable. Shame there are only 2 drive bays in an 840av or I'd have lobbed a 3rd boot drive in there and kept it like that.
Even niftier is that Media 100 2.6.1 will happily output a digital export video (Quicktime MJPEG) larger than 2gig. Quite a feat for a program written when single disk drives larger than 2gig were just appearing.
Dunno if the 840av does that. Not gone that far. I think at most i managed 800MB once.
I need to test and see if it'll capture beyond 2gig or if that's hard coded into the software. In the mid 90's, Mac OS did not support files over 2gig, not even on HFS+.
Maybe by 8.1 it did?
-- Mark Benson
AIM - SilValleyPirate MSN - [EMAIL PROTECTED] Visit FlatPackMacs online: <http://fpm.68kmac.com> Visit my Homepage: <http://homepage.mac.com/markbenson>
"Never send a human to do a machine's job."
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