[opendtv] Re: France bids farewell to SECAM
- From: Olivier Houot <olho_avatar_i@xxxxxxxxx>
- To: opendtv@xxxxxxxxxxxxx
- Date: Thu, 08 Dec 2011 21:41:40 +0100
Albert Manfredi
> > Isn't it true that many modern NTSC sets still include an
> > automatic skin tone correction ?
>
> Not that I've seen, since the 1970s. The RCA set I bought in 1985 did
> not have such a control.
>
I ask that because i read some low cost sets would have this as an
internal automatic adjustment, without the possibility to disengage it.
In that case you may not have an external control, but a correction
would be made nevertheless. No longer true ?
> Could be that Canadian broadcasts were more consistent.
Well that is what i meant by being nervous about using something that
needs to have reliable components or guys all along the way. I'd rather
have a system that can take some punishment and carelessness, and still
deliver a reasonably nice picture, where possible.
> The popular wisdom was that PAL and SECAM were also better than NTSC
> because the pictures were sharper. But in fact, that was only a matter
> of channel width - 8 MHz vs 6 MHz.
>
30% more bandwitdh certainly makes things easier, except perhaps for
SNR : NTSC is generally said to be better in that regard and of course
you need electronics that handle the extra Mhz.
That indeed allowed for more scanning lines, but also, PAL/SECAM use a
gamma correction of 2.8 instead of 2.2 for NTSC, which gives more
contrast and that must be partly responsible for the perceived enhanced
sharpness.
> Wasn't the original French 819 line format transmitted on 12 MHz
> channels?
>
According to this site:
http://www.pembers.freeserve.co.uk/World-TV-Standards/Transmission-Systems.html#CCIR
the channel was 14 Mhz, with only 10 Mhz available for the video signal
(but no subcarrier to spoil things, here).
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