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RE: [AV Media Matters] The FILE is the thing ! Was -Digitizing Audio and Vide
At 03:51 PM 5/28/2003 +0000, James Lindner wrote:
Some good points are raised here. A shorter reply.
And more good points, Jim.
Even with lossless file formats encapsulated within an MXF wrapper we
may need to morph the old MXF into MXF2053 and we may end up with
Little-Endian and Big-Endian problems like we have in graphics and audio
between PCs and Windows--mostly transparent, but still readability
For the record, approximate bit rates:
Bits per second:
DVD (MPEG II compressed) 9.8Mb/s peak, ~4Mb/s average
Consumer DV (DV compression) 25Mb/s
DVC-PRO (and related formats) 25, 50, and 100Mb/s (100 is High Def)
Uncompressed Standard Definition Video 270Mb/s
Compressed High Definition Video 100Mb/s (DVC-ProHD) and
Uncompressed High Definition Video 1500Mb/s
With a DVD, the movie is tweaked by a "compressionist" to make it fit
a bit budget allocated scene to scene.
So with 10Mb/s one hour is 4.5GB
With 270Mb/s one hour is 121.5GB
With 1500Mb/s (High Def) one hour is 675GB
So, we're still really a few years out from storing 120GB/hr material.
most dense and cost effective storage medium today is Sony's new S-AIT
tape at 500GB (0.5TB) per cartridge for about $225 per cartridge. the
map over the next few years takes this out to 4GB/cartridge.
I believe that it may be possible to get lossless compression at ratios
like 4:1 over a wide population based on a couple of conversations I
have had recently (but this is an area that we will do some more work in
during the next year). Certainly 3:1 over a large quantity of content
seems quite possible - so I think that 30GB (4:1) for one hour of
content is reasonable. There is a vendor that I visited at NAB that was
selling full up 1.5TB NAS RAID arrays with parity and hot swap drives at
around $4000. If you can record 50 hours on that, your per hour cost is
$80. Of course this is only the storage cost, if you think of this cost
as a comparison with tape, you are about 2.2x higher then tape for
DigiBeta tape. Digibeta decks are not cheap, when you fold in the full
system cost, you are approaching a similar cost - still more expensive
but not dramatically so. In another year the cost advantage will
slightly turn towards HD, in 5 years it will be no contest.
Now you might ask - "but how do we make lossless compressed video files
in real time?". At this point I can only say... :) I am working on
that..... and it is clearly an important piece of the puzzle.....
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