[Sharing is fun] – Closed Captioning matrix based processing/parsing

Sep 16, 2007 at 7:03am

[Sharing is fun] – Closed Captioning matrix based processing/parsing

Hello.

Here is a patch I rediscovered that myself and a co-worker created to
parse scanline 21 of NTSC video, which contains closed captioning
information.

This patch parses CC in realtime and converts to a text stream. If
you wish to use a live source, your quicktime based capture card
*must* be able to pass through line 21, most consumer products do not
do this, however, professional broadcast/editing gear does, like AJA
and Decklink cards.

Anyway, ive included an example CC encoded movie at NTSC rates for
you guys to get the idea.

Check it out, lots of fun to be had. You might need to ‘tune’ the
offsets depending on the incoming analog or digital signal, as they
ADC conversion or H/V sync may put the horizontal offset of the CC
encoding off by a bit.

Ive also included some max performance optimization notes, my co-
worker wrote this patch, and i tuned it. Ive lost his original patch,
but it went from ~ 20fps to around 400.

patch:

http://abstrakt.vade.info/ILOVETHEMAXLIST/ClosedCaptioningRevised.zip

example video:

http://abstrakt.vade.info/ILOVETHEMAXLIST/CC.mov

Yeah, I know, its not OpenGL, but good old Jitter can still do some
fun stuff.

v a d e //

http://www.vade.info
abstrakt.vade.info

#33694

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