[mythtv] automatic 14:9 or 4:3 zoom based on black bars detection?

Chris Edwards chris.edwards at gmail.com
Wed Jul 19 04:15:05 UTC 2006

On 6/26/06, Daniel Kristjansson <danielk at cuymedia.net> wrote:
> BTW2 The above will fail for when there are ads in the letterbox
> bars. They do this on some HDTV sports shows that are filmed in
> 4:3 but broadcast in 16:9. So far these ads are static so they
> would be fairly easy do detect with a simple add on to the above
> function. Simply subtract two frames 30 seconds apart for before
> running the above on it. This will give you some bogus values,
> and a lot of failed detects, but if you run it in the commercial
> flagger like in BTW1 then you will get the correct result in the end.

This would be a bit of a problem in Australia. Most shows are 16:9,
but not all. Ads are quite a mix. I don't know how quickly and
seamlessly the video can be zoomed/unzoomed etc. If it can be done
seamlessly, it would be very handy to have a feature like this. I
imagine a preprocessor like the commercial flagging would have to be
done to mark where the aspect ratio changes.

Since I have a 16:9 tv, and all broadcasts here are in 16:9 (with
black bars on either side when neeed), the main use would be to zoom
in to 16:9 material being broadcast letterboxed within the 4:3 area.
Automatic zooming for that would be great :-) There are some difficult
cases though, like when the subtitles go outside the area where the
picture normally is.

Chris Edwards

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