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AJA IO vs AJA Kona - Deck Link

Published : 24th September 2003

Does anyone know the difference in quality between a SDI signal going thru a box such as AJA IO Firewire and a signal going thru a PCI SD card such as the Deck link, cinewave or kona? Is actually the same quality, even your SDI signal passes through the firewire? I am stepping up to DVCPro 50 as my lead format in my facility and I am not sure which PCI card or box is better to preserve the best quality when editing NL

Thanks

Armando Montoya

Post-producer/Director

Monterrey N.L. Mexico

Armando Montoya asked :

>Does anyone know the difference in quality between a SDI signal going >thru a box such as AJA IO Firewire and a signal going thru a PCI SD >card such as the Deck link, cinewave or kona?

There should be very little difference between AJA I/ via Firewire and the AJA Kona PCI adaptor. Both acquire uncompressed serial digital component video. In the case of the IO, the Firewire is just a transport path (think of it as ethernet). I don't have any information about Deck Link or Cinewave adaptors.

There may be minor differences in the format you choose to store the uncompressed video. This is determined by the vendor's codec software. The AJA Kona web page specifies that "QuickTime V210 10-bit YUV format" is used by its codec. In addition, there seems to be other uncompressed video formats available (8 bit RGB for example) as well as translation to DV and JPEG compressed formats.

The AJA IO definitely captures uncompressed 10 bit digital component video and can store in the same YUV format. The codec also can capture directly to other formats including compressed DV and JPEG if that is what you want.

The only differences I can see between the two AJA methods are that the Kona card can do reverse telecine (remove the 2:3 pull down) during capture and supports real time playback effects to avoid rendering some segments.

All of this information was grabbed from glossy brochures I picked up at NAB-- I don't have direct access to the real stuff and so this is not real world experience! All the AJA parts seem to be designed for Final Cut Pro (and by extension QuickTime.) Other edit and capture applications may or may not be able to take advantage of these codec options.

David Tosh

>Does anyone know the difference in quality between a SDI signal going >thru a box such as AJA IO Firewire and a signal going thru a PCI SD >card such as the Deck link, cinewave or kona?

A trip down SDI memory lane......

There can be a substantial difference in quality to the signal - a seen over multiple generations a test we have ran while evaluating gear is.

First get your hands on a good known uncompressed SDI recording device, the ones we have used are the old school Abeakas A66, Accom's WSD, Pronto DDR, or a Sony or BCS D1 machine in good shape. Some we have tested and found lacking are Pluto, Serira, Profile and any compressed SDI device like Digbeta/Dcv Pro50 run some contrasty/ saturated footage in through the SDI board, add a key the say "1", the output to the uncompressed device.. repeat twice as many times as you ever think you will need to see any image go through the system, we use 30 passes, on each pass add a new key....

When you have had enough then difference key the last pass over the first pass - (I use Shake), set the difference key value to 1 All the 1 -> 30 numbers should show up. Anything else is artifacting.Gear that flies through this process is old school box's like Avid's uncompressed tools, Abekas, Accom, Quantel & DS all do very well as they do not do a forced color space conversion to RGB.

Box's that fall apart are ones that force color space conversions - Cinewave, high end Discreet, all fail this repeatably. Have also seen problems with Bluefish running under OsX, seems to drop the bottom line from the raster and replace it with a line of white pixels. Although this will not create any visible issues once broadcast - it will cause instant rejections from any broadcaster.

The bottom line is that video is YUV color space and you bring it in from YUV, and play it out to YUV, the conversions to RGB really hurt and do no useful good. Many of the cards you are looking at will only do RGB.

Test.test.test - you may be in a place where you do not need the ability to archive and retrieve footage, commercials are one place where this is true, long form usually goes 5 -> 10 generations by the time. Textless masters with special audio for promo purposes are called for 6 months after the show was last archived - this is where a poor purchasing decision or lack of testing can come back to bite you in a tender spot - your wallet as show masters are rejected by broadcasters.

Test.test.test............

Dermot Shane

VFX Guy

Vancouver, Canada & Shanghai, China

>I am stepping up to DVCPro 50 as my main format in my facility and I >am not sure which PCI card or box is better to preserve the best quality >when editing NL

Actually, if you won't use analog video or another digital format than DV and DVCPRO50, you don't need a capture card at all. Final Cut Pro 4 supports DVCPRO50 codec. Thus, with a Firewire enabled Mac, FCP4 and a Firewire enabled DVCPRO50 deck, you can transfer your video without ever loosing a bit (since the hardware connection is ok, of course) and going through any kind of A/D, format, or color space conversion.

Andre Moura

Tech. Support

Audio & Video

Ass. Torre de Vigia

SP - Brazil

>Box's that fall apart are ones that force color space conversions - >Cinewave, high end Discreet, all fail this repeatably. Have also seen >problems with Bluefish running under OsX, seems to drop the bottom

Dermott,

CineWave stores SD and HD video in uncompressed ITU Rec. 601 YUV 4:2:2 format, with no format or color-space conversions. In layman's terms: the bits that come into the SDI connector are the bits that are stored on disk - and become the bits that are played out again.

Software applications like Final Cut Pro and QuickTime Player will take advantage of the native Rec 601 format for recording, playback, and effects processing. Applications that only work in RGB-space (e.g. After Effects) will require a conversion to and from RGB - but this is true for ALL I/O solutions.

Justin R. Allen

President & CEO

Katana Interactive

www.katanainteractive.com

>CineWave stores SD and HD video in uncompressed ITU Rec. 601 >YUV 4:2:2 format, with no format or color-space conversions.

Hey Justin!

ThanX!

I just checked the pinnacle website.and yes nothing stands still! They have seen the light! They used to try to sell RGB as an advantage - mainly because it was all they could do... and some fools bought into that - glad to know that even the marketers of BS can come around in the face of the obvious technical shortfall. they now offer the choice of YUV or RGB, and that is a good step forward.

I will re-test the newest board when I have the chance & need it fell apart in earlier incarnations that were locked to 10Bit RGB - guess that leaves Inferno, Flame, Fire & Smoke as the only one out there (at least until Liniux box's show up next year...) that force a RGB conversion.. they are running on decade old code that relied on now totally out-dated hardware.. they have no choice but to pedal this hooey - for now - will change mightily once they can use YUV I bet.

Yes if 4.4.4 Viper or film -> film is your work flow then RGB is the best way, and having the choice is pretty important in the real world the latest Cinewave may fare much better than the older one I tested - always better to know before a purchase.

My closing statement of Test.test.test still stands, your mileage may vary, and if through testing is done then your card might pass - and that is really the most important point - test it, test it in the world you will live in, test it to break it, test it to find the flaws, be cruel...

My clients are expecting the very best from me everyday - and I use tools that keep up with out excuses or hype, glad to see Cinewave join the world I live in...at least worth testing again.....

I used Shake, for the tests, in YUV for the cards that supported YUV, RGB for the RGB cards, that to keep any software color space conversions out of the picture - to be a fair as possible - and discreet was done separately with both a Onyx/Srirus and a Floctane....

Dermot Shane

VFX guy

Vancouver, Canada & Shanghai, China

Thank you guys for the info very useful. did not know about the YUV and RGB conversion...

Armando Montoya

post-producer / director

Monterrey N.L.

Mexico