Kramer Composite-YC Transcoder

[wiseant]

Hi All

My brother gave me a Kramer Composite-YC Transcoder Model KR-10

Just curious if anyone has any experience with units like this

I hooked up my VCR composite to this unit with SVideo out going into my capture card
The capture was noiser and brighter than the same capture done with composite
I used 640x480 huffyuv interlaced

Here are the specs for FC-10 which looks pretty much the same as my unit:

Product Description
INPUTS: 1 composite video 1Vpp/75? on a BNC connector. 1 s-Video: Luma: 1Vpp/75?, Chroma: 0.3Vpp/75? on a 4p connector. OUTPUTS: 1 composite video 1Vpp/75? on a BNC connector. 1 s-Video: Luma: 1Vpp/75?; Chroma: 0.3Vpp/75? on a 4p connector. MAX. VIDEO OUTPUT: 2.5Vpp/75?. VIDEO BANDWIDTH (-3dB): 10MHz (YC in CV out). DIFF. PHASE: 0.3°. DIFF. GAIN: 0.36%. K-FACTOR: 0.05% (YC to CV). LUMA S/N RATIO: 79dB. POWER SOURCE: 12VDC, 110 mA. DIMENSIONS: 16.5cm x 12cm x 4.5cm (6.5” x 4.7” x 1.8”) W, D, H.

TIA
wiseant

[edDV]

There is a fundamental flaw in this approach.

Ideal VCR capture requires

VCR -> Y/C split* -> A/D -> TBC & processing -> File

A standalone TBC adds an additional D/A then A/D. Most also export analog composite which forces another lossy Y/C split.

VCR -> Y/C split* -> A/D -> TBC -> D/A -> Y+C combine -> composite video -> Y/C split A/D -> A/D -> file

The Kramer FC-10D adds yet another D/A then A/D. Each of these are lossy.

VCR -> A/D ->Y/C split* -> D/A -> S-Video -> A/D -> TBC -> D/A -> Y+C combine -> composite video -> Y/C split A/D -> A/D -> file


* Y/C separation is a complex and lossy process. In the past it was an analog process that preceded A/D. Less expensive products used a simple notch filter. Premium products used line delays as a comb filter. In recent designs, the comb filter Y/C separator has been absorbed into video capture chipsets. This happens after A/D. Quality varies.

PDF tutorial http://www.intersil.com/data/an/an9644.pdf

[wiseant]

Thanks for the info edDV

I did read an9644.pdf

I did manage to find a pdf manual for this Kramer transcoder

"To convert from Composite and Y/C to Component video, a color encoder or color decoder is needed, with very complicated circuitry. The color encoder receives the component signal, and must create a chrominance signal by extracting the blue and red information from the component video signal and by modulating this information using the color subcarrier signal. The color decoder performs the opposite: it removes the color subcarrier and extracts the color difference signals to create the video “components”.

"Video Transcoders - are bi-directional converters operating simultaneously in different directions, such as converting from RGBS to Y, R-Y, and B-Y in both directions in the same machine, going from composite to Y/C, bi-directionally or performing color decoding and encoding in the same machine at the same time."

"The decoding from composite to Y/C is done digitally using an adaptive comb filter and DSP [Digital signal processing] techniques to minimize dot-crawl and cross-color. A built-in vertical enhancer circuit reduces noise and dot-crawl on the Y signal."

So, if I understand this correctly, VCR [Composite] -> Y/C -> S-Video

to achieve the Y/C split requires A/D then to SVideo requires D/A and regardless of the conversion technique it is always a lossy process

As well, my SA7134 chipset probably does a better job . . .

EDIT: Looks like this is what it is designed for:
"Using PC Graphics in YC Production
Some scan converters, which convert VGA/XGA graphics to video, generate only a composite video signal. The FC-10 converts composite video signal to s-Video (YC), thus enabling usage of computer generated graphics in professional YC productions, as shown in Figure 10. Perform the following steps (as necessary):
1. Connect a composite video source to the CV IN BNC connector of the FC-10
2. Connect an YC acceptor to the YC OUT 4P connector of the FC-10.
3. Operate source, acceptor and the FC-10. "




Thanks again