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SDI 10 Bit vs. DVCPRO50 with 8 Bit


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#1 EuropeDOP

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Posted 18 May 2005 - 09:53 AM

DVCPRO 50 codec uses 8-Bit compression but with an installed SDI Board in the SDX 900 it is possible to output SDI 10-Bit uncompressed. As far as we understood the Goodman Guide SDI 10 Bit has more color information.

Is the difference visual noticeable? Has someone tried it? We are going for a filmout.

If I want to use the SDI Option for output can I use a "SDI to FireWire" converter to capture SDI 10 Bit uncompressed with something like the "AJA IO LD Box"? Is it possible to make a SDI to FireWire connection to an Apple G4 Powerbook?
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#2 Stephen Williams

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Posted 18 May 2005 - 12:28 PM

DVCPRO 50 codec uses 8-Bit compression but with an installed SDI Board in the SDX 900 it is possible to output SDI 10-Bit uncompressed. As far as we understood the Goodman Guide SDI 10 Bit has more color information.

Is the difference visual noticeable? Has someone tried it? We are going for a filmout.

If I want to use the SDI Option for output can I use a "SDI to FireWire" converter to capture SDI 10 Bit uncompressed with something like the "AJA IO LD Box"? Is it possible to make a SDI to FireWire connection to an Apple G4 Powerbook?

<{POST_SNAPBACK}>


Hi,

For a filmout, keying or colour correction 10 bit is better.

Stephen
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#3 EuropeDOP

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Posted 19 May 2005 - 01:40 AM

Thank you for your answere, Stephen.

We will make a trial with SDI 10 Bit captured on a Macintosh Powerbook and G5. We will use the P+S Technik Pro35 Adpapter with Zeiss Primes.

When the tests are done we will post our experience.


(Stephen, you have some great shots on your webside!)
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#4 Frank Barrera

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Posted 19 May 2005 - 07:32 AM

presumably your test will include a film transfer. be certain to test with AND without the 35 adaptor. the adaptor may prove to be too soft on the big screen. instead of the Zeiss primes you could try the Digi Primes or simply a Fujinon HD Cine style zoom. You may be surprised at the results.

good luck
FB
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#5 Phil Rhodes

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Posted 19 May 2005 - 09:23 AM

Hi,

Presumably this firewire convertor is comes with custom software to capture whatever data stream it outputs? I ask because my assumption would be that anything advertised as an "SDI to firewore convertor" would give you DV compressed video-over-1394, not uncompressed. Presumably this device you mention is an exception?

Phil
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#6 Phil Connolly

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Posted 19 May 2005 - 11:01 AM

Hi,

Presumably this firewire convertor is comes with custom software to capture whatever data stream it outputs? I ask because my assumption would be that anything advertised as an "SDI to firewore convertor" would give you DV compressed video-over-1394, not uncompressed. Presumably this device you mention is an exception?

Phil

<{POST_SNAPBACK}>


The AJA IO will capture a 10bit SDI source and spit and an uncompressed 10 bit signal down firewire
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#7 Peter J DeCrescenzo

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Posted 19 May 2005 - 06:34 PM

The AJA IO will capture a 10bit SDI source and spit and an  uncompressed 10 bit signal down firewire

<{POST_SNAPBACK}>


Yes, AJA has been demoing this at trade shows for a couple of years now; I've seen it demoed myself and it seems to work well. The original IO and the IO-LD devices convert standard definition SDI to Firewire 400 as an "uncompressed" 10-bit 4:2:2 digital datastream. It's _not_ compressed using the DV25 codec.

For this to work the hardware configuration must consist of: A fairly recent Apple PowerBook laptop or Mac desktop computer with a G4 processor 1.67GHz or faster. Connect the IO or IO-LD devices to the computer's built-in Firewire 400 or 800 port. Install a 3rd party Firewire 800 interface card in the computer. A 15" or 17" PowerBook will accept a FW800 PC Card such as available from LaCie. Connect a "fast" (at least 7200 RPM) 3rd party FW800 external harddisk drive to the add-in FW800 card. The capture software (such as Final Cut Pro) will capture the in-coming uncompressed SD video to the external FW800 HDD.

The reason the above configuration is necessary is because most (all?) Macs have only one internal Firewire bus. Some Macs have two FW connectors (FW400 & FW800), but there's still only one FW bus. The datarate of uncompressed SD is high enough to nearly saturate the internal FW bus, and there isn't enough headroom remaining to also transfer the data to an external HDD connected to the same bus.

The add-in FW800 card adds a second FW bus to the computer, and with the external HDD connected to it, the computer will have enough throughput to handle the load.

I suspect more information is available from AJA on this configuration and any recent recommendations they may have concerning it.

Of course, the above approach mostly makes sense if you wish to capture "live" uncompressed SDI video directly from a camera, not playing back from tape. Tape playback will always include the tape format's compression, whereas "live" camera video via SDI is (for purposes of this discussion) uncompressed.

All the best,

- Peter DeCrescenzo
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#8 Phil Rhodes

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Posted 20 May 2005 - 09:34 AM

Hi,

> The datarate of uncompressed SD is high enough to nearly saturate the internal FW bus,

Well; no - 10bit SDI is 270Mbit/sec; Firewire 800 is.... 800.

However yes you would be out of room trying to go camera to PC and PC to disk on a FW400 bus.

Phil
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#9 Peter J DeCrescenzo

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Posted 20 May 2005 - 12:11 PM

Hi,

> The datarate of uncompressed SD is high enough to nearly saturate the internal FW bus,

Well; no - 10bit SDI is 270Mbit/sec; Firewire 800 is.... 800.

However yes you would be out of room trying to go camera to PC and PC to disk on a FW400 bus.

Phil

<{POST_SNAPBACK}>


Hi Phil. Yes, that's right: Since the AJA IO boxes use FW400, the Mac's FW bus throttles down to FW400 speed, even if the IO were connected to the Mac's FW800 port. When also using an external FW HDD, you need the add-in FW card to establish a 2nd FW bus to avoid overloading the internal FW bus.

All the best,

- Peter DeCrescenzo
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#10 EuropeDOP

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Posted 13 June 2005 - 04:24 AM

We tested the SDI Output Option of the SDX 900 with an Apple G5 and an "AJA Kona2 Capture Card". We hoped to receive an advantage with a 10 Bit SDI Output for a greenscreen shot.

Unfortunately the AJA Card recognized only a SDI 8 Bit output signal and it seems that the SDX 900 has no 10 Bit SDI Output. Well, can it be that the Goodman Guide is wrong or is there a (secret) switch button between 8 and 10 Bit SDI Output?

Beside that, the capturing without a deck worked fine.
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