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Discussion Starter · #1 ·
I would like to record uncompressed HD through SDI. The data rate is 1.485 Gbps. I am thinking of four or five U320 SCSI drives in a Raid 0 or Raid 5 array. Would this be fast enough and are 15K drives needed or is 10K sufficient?
 

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I hope you are aware that you will need around 630 GB per hour of uncompressed HD video.

That is roughly 180 MB/s.

I don't know how fast those SCSI drives are, but I guess you should get the fastest possible.

10000 RPM drives are available up to 146 GB. So, you'd need roughly 5 of them at around $500 ea.

15k RPM drives are only available up to 36 GB at around $500-600 ea. I don't think this would be big enough.

Another route would be Fibrechannel HDD. You should sell your house first, if you want to get them.


Most people use something like the high performance AVID storage solutions for uncompressed HD editing. Either AVID MediaDock Ultra320 or AVID MEDIArray II work with AVID DS Nitris for uncompressed HD

They are extremely expensive, though.

To get an idea: the AVID UNITY 1460 GB MEDIARRAY II RACKMOUNT 10 has an MSRP of US$ 34.075

the AVID MEDIADOCK ULTRA320 LOADED 1.75TB has an MSRP of $ 17.450



A good forum to get an answer to your highly specific question might be the forum over at the canopus site or the AVID forum.

There should be some folks over there that have done this before.


You will also need something like AVID DS Nitris to process the uncompressed HD streams.

AVID DS NITRIS EDITOR SYSTEM WITHOUT STORAGE costs you around $ 70.000.



Just a little information for you


Kai
 

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From a conversation over at the AVID forum:
Quote:
does anyone know how much disk space is required to store 10 hours of HD cassette content?

Also, if a production has say... 45 hours of HD material on cassette, are there current hardware system configurations which allow a post editor to have access to all 45 hours at one time? Is it a normal requirement, in a professional post production editing studio, to have full disk access to all 45 hours of a production i.e. all 45 hours already loaded to disk?

I am trying to find out a bit about this for my son who is in college in Minnesota.

thanks very much


James Murphy answered:

No quick answer here.

First, if you are going to put it on disk, you have to consider your compression scheme. Uncompressed HD is going to chew up hard drive space at an alarming rate, low to high compression is a trade off in quality versus size.


Is the HD content captured at 8 or 10 bit? Is it 1080i or p, 720p, what frame rate? These will all make a difference in terms of the amount of space used. You are likely talking about Terabytes of storage for 10 hours at high resolution HD, either way.


The Avid DNXHD codecs have excellent compression quality at scalable quality/size.


With 45 hours of HD, in a typical post environment, if there is such a thing, it is likely they are working in offline qualities and then taking the resulting finished piece and only recapturing the HD content that is needed to make a master. To put 45 hours of uncompressed HD on disk is going to be VERY expensive, you are talking about rooms filled with drives. The workflow would likely be something more along the lines of:

-Capture at very low resolution the HD content

-Edit the offline quality to a finished piece, so the 45 hours is edited to a 2 hour movie

-Then the 2 hours needed to make the finished piece are recaptured at full resolution. 2 hours of HD storage is going to be easy compared to 45 hours.


I hope this helps,


James Murphy

Avid AE
If you need calculations as to what disc size you're looking to, shoot me some information about the amount of material you'd like to store


Kai
 

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Discussion Starter · #5 ·
Kai,


Thanks for the info. I want to time shift and not archive, although I will be doing most of it with DVB ASI instead of HD SDI with a maximum data rate of about 80 Mbps. I do want the HD SDI capability for some use and I am looking at the HP xw8200 as the platform with five drives. The 15K drives are now available with 73 GB each and the 10K drives with 300 GB each, so five drives can be 1.5 TB. The maximum time storage needed for uncompressed HD is about 2 hours, so that rules out the 15K drives.


I know that this is expensive, even with using a high end general workstation and adding the required i/o board(s) and software.
 

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What are your plans for playback?

Software or Hardware?


Those are questions you will need answered.

Also, most if not all display devices cannot handle (on their inputs) either 80 Mbps for DVB or 1.4 Gb for uncompressed HD. Direct streaming to the displays will thus be impossible. Regular PCs will also not be useable at these data rates. Even a high-end general workstation will not do.

Therefore you will need a system that is capable (due to special hardware)of working in real-time with uncompressed HD. The only one I know is AVID DS Nitris, though there are a few others (costing about the same).


As you can see, storage is the lesser problem (price-wise at least).


Kai
 

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Quote:
Originally posted by PanamaMike
Seems to me that the technology necessary for this functionality exists.

For example , this chip could be used to encode the HDTV signal. All that's needed is someone that could design a board to add it to a PC and a software interface to something like SAGE TV.


Mike
Mike, we are talking about uncompressed HD. That is the format that is normally available to movie editors/studios and the like. Broadcast companies won't even get uncompressed HD material.
 

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Quote:
Originally posted by PanamaMike
Seems to me that the technology necessary for this functionality exists.

For example , this chip could be used to encode the HDTV signal. All that's needed is someone that could design a board to add it to a PC and a software interface to something like SAGE TV.
That doesn't do what you think it does, ie it's not an HD MPEG-2 encoder. It's just an HD version of the TV encoders found on nearly every video card in existance, it's and HD DAC for lack of a better word.
 

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Discussion Starter · #9 ·
Kai,


I am still looking at the i/o options. The ASI data stream will have to be demuxed and handled through an HD MPEG decoder…there are good options for doing this. I am still researching the options for HD SDI i/o.


My display is DVI and HD-SDI only and can handle the SMPTE 292 formats.


What I am really still unsure about is the 10K versus 15K drive issue.
 

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odyssey, I found an interesting product for you:

its the
Doremi Labs Uncompressed HDTV Disk Recorder V1-UHD (pdf)

The unit is available with built-in storage of up to 584GB and external RAID 5 storage of up to 1680GB.

Starting Price is around $40.000, but there is currently a used one available for like $10.000 on one site


Another interesting product is:

Doremi TSS-100 Transport Stream Server


The new TSS-100 from Doremi Labs performs time delay of any ATSC or DVB digital television format, including High Definition 1080i and 720p.

A SMPTE 310M or DVB-ASI signal fed to the input BNC on the back of the system can be delayed up to 13 hours. All video, audio and ancillary data on the signal are fully preserved.

A simple Java based user interface communicates with TSS-100 via 100BaseT Ethernet. The interface allows the user to set the desired delay time and start the delay process.
more info (pdf)


Price for this one is $14.000


Kai
 

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Quote:
Originally posted by odyssey
Kai,


I am still looking at the i/o options. The ASI data stream will have to be demuxed and handled through an HD MPEG decoder…there are good options for doing this. I am still researching the options for HD SDI i/o.


My display is DVI and HD-SDI only and can handle the SMPTE 292 formats.

The HD Fury card does what you need:
HD Fury

Retail is around $ 12.000

another link

Kai
 

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Discussion Starter · #12 ·
Quote:
but there is currently a used one available for like $10.000 on one site
Thanks for the additional info. Which site for the used Doremi?
 

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I still can't even begin to fathom why someone would spend the money needed to do this. It's incredibly limited and requires far too much cash to make it worthwhile. And in the end, you are still likely only recording off the analog video stream.
 

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odyssey, you have PM


Btw, I second what madpoet says.

The only persons to get uncompressed HD are those that do digital film scanning, post production facilities and maybe sometimes the studios.

I don't even know if there are digital HD cams that record uncompressed HD.


If you only want to record what you get through normal broadcast channels OTA/Cable/or whatever, your approach would really be overkill.


Kai
 

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Discussion Starter · #15 ·
I should explain why I want uncompressed HD. I have two professional HD DVB satellite receivers that output HD SDI (Tandberg PMRX5800 and Motorola HDD1000). However, in both cases I have access to the ASI data stream which is much easier to record and that is the main purpose of this system...to time shift SD and HD satellite content. I also have a Teranex unit and I may want to process the decoded HD twice, using two different Teranex software packages. In that case I have to record the uncompressed HD coming from the Teranex after the first software package, which may be film grain removal, followed by a second Teranex software package which offers more advanced de-interlacing, custom colorspace conversion, etc. The i/o for this is HD-SDI.
 

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You might want to look at the Decklink HD from Blackmagic Design . It supports 4:2:2 uncompressed HD SDI for $595. If you need genlock, get the plus model for $995, and if you need 4:4:4 HD, get the pro model for $1995 (after reading the reason you're looking for this, I suspect 4:2:2 is all you'll need). Documents at their support site give details on recommended storage performance. The card's driver comes with a utility to measure your disk speed to determine if it is adequate for the requirements of HD SDI (you could download this in advance if need be). A good site for discussion about this series of cards is Creative Cow's Decklink forum . I have no affiliation with BMD, but I have used the HD Pro model, and was generally satisfied.
 

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Seems to be like a valid application and it even makes sense in that case, given the quality the Teranex unit produces.


Kai
 
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