Re: Mental challenge: the rainbow


On Fri, 10 Feb 2012, Marc S. Ressl wrote:

On 10 feb, 19:55, Vladimir Ivanov <vlad...@xxxxxxxxxxxxxxx> wrote:

On Fri, 10 Feb 2012, Marc S. Ressl wrote:

But the choice of color or monochrome is based upon sampling thecolor> carrierat the beginning of the frame. Do you consider that appropriate?

Yes, you still check for burst on each line.

Little note here - I meant that appropriate is sampling the burst presence on each line, not on each frame.

Which you filter, and the filtered result is what actually drives the
render. Try with Michael's suggested time constant of few frames.

Thanks a lot for the comments. Would somebody be so nice as to refer
me to Michael's post on color carrier detection? I can't seem to find
it :-(.

Me neither. Google is not about searching anymore?

pd: did real monitors detect and enable color carrier recovery only at
the beginning of a frame, or is there a chance the detector toggles in
the middle of a scan line?

The monitors we're talking about, being simple analog devices, most likely switch whenever the color burst detector filter commands - so, yes, anywhere, including in the middle of a scan line. And because then the color PLL is not locked you will get off colors for few lines until it locks.

What I suggested to you is:
 1) sample each line's color burst presence
 2) filter it via simple filter, time constant few frames
 3) render each line monochrome or color depending on filter output

Don't waste too much time over this, Marc. :-)