[plug] SCSI cards

[Craig Ringer]

Michael Holland wrote:
>>8 broadcast-quality video channels per SCSI drive.
> 
> So editors use around 10x broadcast bandwidth per channel? Is this the
> normal ratio of mjpeg to mpeg2?

It seems more than reasonable for max-quality MJPEG, which is what one 
would want to use (JPEG is lossy, after all). I wonder what MNG (or 
"MPNG" in the same style as MJPEG) would be like as a video editing 
format, being lossless and all.

>  It would seem a bit excessive these days. Why not keep mpeg2 on disk,
> and decode it real-time into memory buffers for editing?

Because editing and re-encoding MPEG results in awful quality loss. 
Also, because MPEG mingles frame data across quite a few frames (all 
fames between keyframes AFAIK), it's very bad for frame-by-frame editing.

Try decoding and re-encoding an MPEG stream a couple of times and you'll 
see what I mean. *shudders*.

>>A single PATA running at 7200 rpm is _enough_ for broadcast-quality
>>editing; but you have to be patient. If you stripe and mirror across
>>4 drives, then there's ample bandwidth.
> 
> I'd like to see an editor that will do 'mark-ups', and show it as best as
> it can (draft) in real-time.

I could've sworn I heard about one or more that some already did that. I 
don't really use this stuff much myself, though, and I can't remember 
names. It might've been the latetst Premier; I'm not sure.

--
Craig Ringer