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Old April 14th, 2008, 04:17 PM   #1
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Is lossless/uncompressed direct to disk even possible?

just wondering out loud here.

in order to capture 1920x1080p24 @4:2:2 lossless/uncompressed, you would require:

1920*1080*24*24bits per second=142.382812 MBps

i haven't read about many SSD's with that write speed and the ones that come close are extremely expensive and can't interface w/cam.

7200rpm hard drives can write upwards of 60MBps and 140ish if you have raid0.

most of the tapeless solutions use a compression codec to drop information in order to fit the needs of portability.

say, you do get a dual raid0 7200rpm 2.5" laptop drives that can achieve 150MBps, can you simply use vegas to capture 1080p24 uncompressed or do you still require additional programs?
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Old April 20th, 2008, 03:23 PM   #2
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We are currently writing 3.2 Gbps to an array of 8, 2.5" drives in RAID 5, inside of an ICON (http://colorspaceinc.com/icon/) media pack.
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Old April 21st, 2008, 09:04 AM   #3
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wow, how portable is that? do u need a backpack?
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Old April 22nd, 2008, 12:26 AM   #4
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No backpack needed, it is battery powered and weighs about 10 pounds.
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Old April 26th, 2008, 07:46 PM   #5
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Quote:
Originally Posted by Yi Fong Yu View Post
just wondering out loud here.

in order to capture 1920x1080p24 @4:2:2 lossless/uncompressed, you would require:

1920*1080*24*24bits per second=142.382812 MBps

i haven't read about many SSD's with that write speed and the ones that come close are extremely expensive and can't interface w/cam.

7200rpm hard drives can write upwards of 60MBps and 140ish if you have raid0.

most of the tapeless solutions use a compression codec to drop information in order to fit the needs of portability.

say, you do get a dual raid0 7200rpm 2.5" laptop drives that can achieve 150MBps, can you simply use vegas to capture 1080p24 uncompressed or do you still require additional programs?
Actually, the required bandwidth for 1080p 4:2:2 10-bit is:
1920x1080x20(bits)x24(frames/sec) = 124.4 MBytes/sec as you should capture in YCbCr 10-bit color space, not 8-bit RGB (which I assumed you were using for your calculation).

We will offer an uncompressed option this Fall to our portable solid-state recorder Flash XDR. The record time in uncompressed is not long (8 minutes with four 16GB cards), but Flash XDR is very portable (about 2 lbs) and very rugged. You can also record at 160 Mbps I-Frame only MPEG2, which is very close to lossless (visually).
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