[opendtv] Re: France bids farewell to SECAM

  • From: Mark Schubin <tvmark@xxxxxxxxxxxxx>
  • To: opendtv@xxxxxxxxxxxxx
  • Date: Thu, 15 Dec 2011 17:53:43 -0500

I was not referring to correction but color change. We would sometimes intentionally make people look green in a commercial for a digestive aid or pull down chroma completely for a black-&-white picture. There was nothing non-standard about the resulting picture; the proc amp replaced the burst.


Fancy color manipulation is something else. It is, indeed, easier in component, but, even then, one might like to go to secondary and other colors. There were NTSC-based color-modification systems for those who wanted full grading controls.

TTFN,
Mark


On 12/15/2011 5:05 PM, Olivier Houot wrote:
Mark shubin wrote:
Well, you need to change one (the burst or the subcarrier in the
picture) relative to the other.  It's a routine operation for
processing
amplifiers (proc amps).

So you can achieve both phase and amplitude modification by touching the
burst, as it is outside the modulated part of the video line (at the
price of potential non compliance)? Or, for amplitude would you try a
comb filter with adjustable gain ?

But i think i used an incorrect word when i asked my question about
color correction. To you it probably means : to compensate for any
unintended drift in chroma that would have occurred during processing.

But perhaps i should have said: color modification. In component you
would have the capability to tweak the amount of red, green or blue
primaries at will. But in the modulated signal you would have to adjust
independently the luma (which mostly contains green but still has an
amount of red and blue components) R-Y and B-Y, so you would have to
compute a modification of those three that achieves the correct
primaries ratio, despite their relationships, and apply them to each
targetted part of the signal despite the fact they are all mixed
together in the composite signal. It does not seem reasonable, so i
suppose for this you do have to demodulate.

Or would you say this kind of color modification is not needed very
often in the profession anyway?



----------------------------------------------------------------------
You can UNSUBSCRIBE from the OpenDTV list in two ways:

- Using the UNSUBSCRIBE command in your user configuration settings at 
FreeLists.org

- By sending a message to: opendtv-request@xxxxxxxxxxxxx with the word 
unsubscribe in the subject line.





----------------------------------------------------------------------
You can UNSUBSCRIBE from the OpenDTV list in two ways:

- Using the UNSUBSCRIBE command in your user configuration settings at FreeLists.org
- By sending a message to: opendtv-request@xxxxxxxxxxxxx with the word 
unsubscribe in the subject line.

Other related posts: