Digital 8 camcorder. Actual color resolution for optical shooting.

[Grigory]

Hi,

I am searching for information:

What is actual chroma components resolution of Digital 8 camcorder when it shoots a scene?
I know that DV PAL format has 250 lines of chroma resolution in digital domain.
Who knows what chroma sampling rate is used inside the CCD-to-DV path?

I have serious feeling that it is about 100 lines horizontally. Any ideas?

Grigory.

P.S. The value of 100 lines is not bad - not worse than for Hi8, I suppose. Just want to find correct info for low cost DV camcorders.

[A_BIT]

Hi,

I don't actually know the answer but I think if you know how to read these specs you might be able to find out?
http://www.sel.sony.com/semi/PDF/ICX209AKB.pdf

-or, maybe-
http://www.sel.sony.com/semi/PDF/ICX209AK.pdf

BTW, thanks for your input on the D8 black borders.

-Anthony

[Grigory]

Anthony,

Many thanks for your links. An interesting reading that helps to understand many things better.

Some of the explanations in documents are still unclear. The first one is what CCD is used in D8 camcorders. My manual for eastern PAL version says about 800,000 gross pixels with ~400,000 used as active. There is no CCD chip in a list with such number of pixels.

I understood that CCD device:
a) use 2x2 light sensors to produce luma component that is an average of four signals from them.
b) produce one chroma component per line only. The second component is taken from the previous line of a field.


If I take that active CCD area in D8 CCD is the same 400,000 pixels as for devices, described in documents, them the effective luma bandwidth is 6.75 MHz by ZERO level. Because of averaging signals from adjacent pixels, the frequency responce has cosine shape.

I got 400 + ~20 lines of luma resolution in my tests with printed pattern. This is reasonable value for a given CCD design.

Vertical luma resolution is also lower than the number of lines, because of vertical averaging.

The luma part fits reasonably into DV specifications, being only 20% below the DV limit.

Sony suggests to limit the chroma bandwidth to 1 MHz in CCD calibration procedures. This looks like serious step back from DV limit of 250 lines.

I found chroma bandwidth on D8 analog output to be approximately 1.5 MHz on digital test pattern, converted into DV movie and played on S-video monitor (Avermedia TV Phone capture card).

I have to take that the chroma bandwidth for camcorder-shot movie is about 1 MHz only. Is it correct?

Well, it is not surprising that I could not detect any DV compression artefact in my footage - the image on the codec input is filtered well below the DV artefacts visibility level.

BTW, digging around this, I found:
1. The quality of Canopus DV Raptor overlay channel is comparable to a composite input of low end TV. Chroma resolution is very bad and luma and chroma components are misaligned.
2. PAL D8 camcorder can work with NTSC DV video, and generates NTSC 4.43 analog video, which is displayed in B/W on Canopus overlay window. Multisystem TV works fine. Canopus card cannot be used well for NTSC signal editing on PAL D8 camcorder, because the card cannot display NTSC 4.43 in color in overlay window.

3. IMPORTANT! Canopus has a bug inside their own PAL DV codec. The codec mixes color components between the fields in a frame. This may cause visual defects on fast motion scenes, and reduce the quality of MPEG2 coding.

You can read the full story on Canopus users forum.

Grigory