Portable HD-SDI Recording Options

[Serge Victorovich]

James Rhodes

So I have done some research on the CineRAM, the 8GB entry level version starts at $18,645.00 not sure about the 16Gb version. I'm speaking with some poeple , but the Baytech Cinema Site is down and the contact number I found is no longer in service so that isn't a good sign.

HD Flash DVR less expensive than CineRAM. James, check this tread:
http://www.dvinfo.net/conf/showthread.php?t=52964

[Yi Fong Yu]

i posted this question on direct to disk forum and no1 seems to know.

has anyone made a record to 3.5" hard drive yet? they have SATA2, 500GB drives =). think about that. just 1 drive can give you 456.25GB or roughly 7 and 1/2 hours of hi-def (based on 1GB=1minute). dunno how that converts into uncompressed 1080i. how much does 1080i take up via SDI?

it seems that it's only logical. those firestore solutions only does 80GB.

[David Newman]

uncompressed 1080i HS-SDI = 1920x1080x30(frames)x2(bytes= for 8-bit 4:2:2) = 120MBytes/s, about 3 and 4 times the speed a single drive can sustain. 10-bit uncompressed from HD-SDI is 150MBytes/s. It is for this higher data rates CineForm is working with Wafian to build HDSDI compression solutions -- allowing a 500GB drive to store 7 hours of 10-bit data.

[Yi Fong Yu]

but a single hard drive can't sustain 150MB/s. only raid0 and a few hard drives will get you that. you're right... this is why no1's made one yet =). very interesting...

thx for clearing that up.

[Kevin Shaw]

Originally Posted by David Newman

It is for this higher data rates CineForm is working with Wafian to build HDSDI compression solutions -- allowing a 500GB drive to store 7 hours of 10-bit data.

Which brings us back to the question of whether a single 3.5" drive could be configured in a battery-powered device to capture to a compressed format like Prospect HD. If I understand correctly, 10-bit Prospect HD requires less than 20 MB/sec sustained throughput, so theoretically well within the capability of today's fast hard drives. I have an external USB2 hard drive with a standard 2.5" laptop drive in it, and that even scores close to 20 MB/sec on one performance test while running off the power in the USB cable. How hard could it be to build something based on a 3.5" drive which can sustain 20 Mb/sec reliably?

[Yi Fong Yu]

how does prospect HD look in quality vs. HDV? i mean if it's roughly the same, HDV takes care of most of those application. the focal point of HD SDI would be uncompressed cap, right?

[Kevin Shaw]

Originally Posted by Yi Fong Yu

how does prospect HD look in quality vs. HDV? i mean if it's roughly the same, HDV takes care of most of those application. the focal point of HD SDI would be uncompressed cap, right?

Prospect HD is a higher quality format than HDV in several ways, but at a data rate much more manageable than uncompressed HD. Avid has a similar codec for similar reasons: uncompressed HD is simply too much data to manage effectively for most projects, but HDV is too compressed to be considered robust enough for demanding video work. With HD-SDI you can capture to a variety of formats all the way up to uncompressed HD, plus on the XL-H1 you can opt to record to HDV if you don't need anything more than that.

[Yi Fong Yu]

meaning less compression artifacts? blocky pixels?

[John Mitchell]

Originally Posted by Yi Fong Yu

meaning less compression artifacts? blocky pixels?

Well it's a 10bit codec for starters, so better than 8bit DVCProHD and because it's frame based you can edit more simply than HDV native )it's much higher data rate than HDV native). There's a thread in HD100 forum where David Newman CEO of Cineform has chimed in.

Looking at their website tests etc it looks a very viable option to uncompressed.