[mythtv-users] Digital Signal decoder
mythtv-list at dinkum.org.uk
Wed Mar 9 16:23:09 UTC 2011
On 9 Mar 2011, at 15:07, Raymond Wagner wrote:
> I would absolutely LOVE if the ATSC spec actually supported such graphics independent of the primary video stream. That way, weather warnings and news tickers could actually be ignored, rather than wrecking a recording you're watching six months after the fact, with information no longer of any relevance.
The mpeg2 spec does actually support this sort of thing, I did a feasibility study many years ago for user selectable sports graphics, choose which extra ones you want to
see sort of idea. Sadly that little aspect of the specification didn't get supported on any of the decoder chips the customer's set top boxes were using at the time, worked nicely in the lab though.
I saw it used on a DVD some years ago to overlay the silhouette of the back of the director and producer's heads while they were waffling through the directors commentary :-) Would be great if they would put the deaf signing people on that sort of overlay layer too, that way they could sign all broadcasts without messing up the late night recordings that myth sometimes chooses!
Can't see any of the broadcasters I work with choosing to make their promo graphics optional, they always seem to want to add more of the horrendous things. The latest trend is for permanently on screen animated graphics, bleucch, it's enough to drive you to dvd & bluray :-(
The new in band 3D spec uses a similar method to pass an optional L-R difference layer alongside a regular broadcast.
There's loads of wonderful little things like this is the mpeg2 & 4 specs, very few of them get used so the implementations are dodgy or completely missing, which further discourages broadcasters from using them.
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