RT.X100 colour correction abilities?

[funky-d-munky]

I am very interested in the RT line of products, they seem very promising as a way of getting the most out of a mini-dv format.

The built in colour correction- how good is it? I understand Colour Correction is limited to 7 parameters in the RT.X10 vs. 16 parameters in the RT.X100. How does this compare to dedicated processing tools like SA Video Finesse

http://synthetic-ap.com/products/vf/

or Vixen?

http://www.xentrik.demon.co.uk/ViXen/vixen.html

Vixen allows selectable processing in 4:4:4, 4:2:2, 4:2:0 or 4:1:1 colour sub-sampling modes. Would this be compatable with the RT upsample? Also if Video Finesse can not work in 4:4:4, 4:2:2 would this make it non compatable with the RT?

Colour keying is one of my main needs.
With the realtime chromakey/lumakey engine, along with the advanced edge artifact reduction it does, the 4:4:4 upsample, anisotropic and bi-cubic filtering present for all timeline work. Does this really make mini-dv a viable studio option( all-be-it for low budget production) Or is it still nesessary to go for Digital Betacam or some uncompressed firewire cam?

Thanks in advance.

[Elie]

I just posted this on another forum to show how good the colour correction of RT.X100 really is.

It was a dark theater and had the XL-1 gain set to auto which produced grainy video.
Also the lighting was a bit strong so I had to corect the footage and the shot called withCC will show how I brought everything back to normal.

Sorry the shots are a bit dark but so was the theater

http://members.rogers.com/2832678523/withoutCC.jpg http://members.rogers.com/2832678523/withCC.jpg


By the way, key framing is one of Matrox strongest points, you can go from colour to black & white with only two keyframes

Regards,
Elie

[funky-d-munky]

Thanks Elie looks good, did you enjoy the concert?
In consideration of the automatic upsampling to the 4:4:4 colour space by the RT.Xseries I was debating on wich CC software to purchase(as listed previously) or whether they were even needed considering the power of an RT.Xseries unit.
I asked the question to Synthetic Apatures the makers of Video finesse, " Does Video Finesse allow selectable processing in 4:4:4, 4:2:2, 4:2:0 or 4:1:1 colour sub-sampling modes? ", so I would know if it will work with digital Betacam and the upsampling of the RT.Xseries. The answer I got is as follow, wich leaves me more confussed then ever!

"No, because there is no advantage to doing so, and, at least theoretically, some disadvantages.

Internally, Premiere does all processing in RGB space. (It is sometimes referred to as RGB 4:4:4, although that's not strictly accurate, as numbers like "4:4:4" and "4:1:1" are really only applicable to component video formats.) Even when you bring in DV-originated footage (YUV 4:1:1 or 4:2:0), each frame is converted to RGB. It is this RGB data, with color data for each pixel, which is passed to filters such as Video Finesse.

After being processed by Video Finesse (and any other filters) Premiere passes the result to your chosen output codec. It that codec is once again DV, it is that codec's job to do the RGB to YUV conversion, and any color subsampling that is needed.

Color subsampling makes no sense in RGB space, as the whole point of color subsampling requires that the luma signal be given more bandwidth than the chroma signal. In RGB, the luma and chroma are not separate. Doing yet another internal conversion to YUV, sub-sampling, and converting back to RGB would only introduce more rounding errors, as well as taking more time.

Also, since subsequent operations within Premiere may require scaling or translation, any sub-sampling that was done would potentially do damage to the image as the sample points are moved and data has to be interpolated from adjacent sub-samples; data that was available before sub-sampling.

If Premiere ever starts using YUV internally, there might be an advantage to working in a sub-sampled space, although there are still advantages to working in a full resolution space, even if the source and destination are sub-sampled.

The less long-winded answer is "No, and you don't want to."

Bob Currier
Synthetic Aperture '

So what is he saying about the RT.X's automatic upsampling? I thought 4:4:4 was better in anycase.
I did not intent to add on to such an already inquizative post but since this objectionable opinion arrived at the same time I thought I would include it .
Any opinions? ?
P.S- the ViXen software dist. by Demon,lists "Selectable processing in 4:4:4, 4:2:2, 4:2:0 or 4:1:1 colour sub-sampling modes"as a product feature.)

[Dr Mordrid]

There is upsampling and then there is upsampling.

First of all he's presuming that the upsample is in YUV space. It isn't; it's to 4:4:4:4 RGBA, meaning it also adds an RGB alpha channel to the stream which is used throughout effects processing.

When plain-Jane Premiere upsamples it's not compositing with anisotropic and bi-cubic hardware filtering, so the results are far different than when using the RT.X cards compositing/effects engine. This makes a big difference in quality, and then there are the advanced filtering features in the RT.X100's keying and correction engines.

As far as "it taking more time" goes, how does he explain that with the RT.X100 you export in realtime and without it you dont? Hmmm....

Dr. Mordrid

[funky-d-munky]

Well I recieved another reply and I think the picture is filling in.

"Your original question was whether or not Video Finesse could work in 4:4:4 , 4:2:2 , 4:1:1 or 4:2:0 space. I answered "no," that we worked in 4:4:4 RGB space, as do all Premiere filters. I'm not sure how that response led to a discussion of compositing and hardware color correction.

Since your purpose is to compare the Matrox hardware solution to using Video Finesse as a software solution, let's compare:

Video Finesse and the RT.X both work in RGB 4:4:4:4 space. (Since Video Finesse doesn't itself do any compositing, we simply ignore the alpha channel.)

Video Finesse relies on Premiere to do any necessary color space conversion from your source material (say, 4:1:1 YUV). This work is actually done by the video codec, and ranges from very good (Main Concept codec, Apple DV codec) to fairly poor (MS DV codec). The good ones use proper interpolation and filtering when upsampling.

The RT.X does the upsampling in hardware, and Matrox says they do a good job. I certainly have no reason to doubt that.

Video Finesse does all it's work in software. The RT.X uses hardware. This boils down to the standard tradeoff: the RT.X is faster and more expensive. Video Finesse is slower and cheaper. How you weigh those two factors will depend on your specific situation.

Regardless which solution you choose, the actual work is being done in the same color space, with the same color sampling and number of bits, so issues of subsampling and such really shouldn't enter into your decision making between VF and RT.X. It's perhaps more important when comparing RT.X to other hardware solutions.

Premiere does a good job of shielding plug-ins like Video Finesse from the hardware details. I'm sure Video Finesse would work fine on an RT.X-based system. Whether or not it makes sense to use VF in conjunction with a hardware-based solution like RT.X is a separate issue. "

Well thats were it stands now. If anyone has any words of clairification lets have them. I sort of understand, then if I think about it too much I get thouroughly confussed :-(

[Dr Mordrid]

Sounds like they are trying to save face

IF they wanted their product to work in concert with the RT.X100 hardware all they have to do is contact developer relations instead of complaining about the hardware being "shielded" by Premiere.

I also doubt that VF does aniso and bi-cubic filtering, which adds to the value of the RT.X100.

Lots of its features would be duplicious, so I guess you would have to compare what is duplicated and then decide if the rest is worth the cost of purchase.

It looks to me like most of VF's features are already in the RT.X100 drivers. The most notable absences are the vectorscope & waveform monitor. Procamps, blurs, color correction, IRE control and many others are in them.

Dr. Mordrid