This freaked me out just a little ...

Chienworks wrote on 10/5/2007, 10:58 AM
Late last night after capturing some old VHS stuff, i ejected the tape from the VCR and of course, whatever was playing on cable started coming through. Between my VCR and the computer i've got an ol' SONY DVMC-DA2 converter box. Fox 40 was playing some homegrown racing news show obviously shot with a consumer grade camcorder. Oddly enough, the preview window in VidCap switched to 16:9 widescreen. I glanced over at the television and saw the 4:3 screen full top to bottom with the same image. The race car tires on the TV were distinctly squished whereas they were very circular in the preview window.

OK, so the converter box did the correct thing and reported the incoming signal as widescreen. But ... this was an analog broadcast. That means that somehow the widescreen info was included in the transmission, received by the VCR's tuner, included in the composite video output, picked up, and recognized by the DVMC-DA2. Wow. Very impressive!

Comments

TheHappyFriar wrote on 10/5/2007, 6:53 PM
impressive? I thought that was impossible!

Chienworks wrote on 10/5/2007, 7:50 PM
Yeah, me too.
Tim L wrote on 10/5/2007, 8:14 PM
I know very, very little about this, but I had been under the impression that aspect ratio data can be inserted in the vertical blanking signal, where closed caption info and v-chip data, etc. are transmitted ("line 21" data, etc.).

I looked all over Wikipedia and only found this brief mention for NTSC:
Both PAL and NTSC have provision for some data pulses contained within the video signal used to signal the aspect ratio (See ITU-R BT.1119-1 - Wide-Screen signalling for broadcasting). These pulses are detected by television sets that have widescreen displays and cause the television to automatically switch to 16:9 display mode. When 4:3 material is included (such as the aforementioned commercial), the television switches to a 4:3 display mode to correctly display the material.

Ref. this page: http://en.wikipedia.org/wiki/Aspect_ratio_%28image%29

(Somewhere else on Wikipedia I had encountered more specific info about PAL signals including this info in their vertical blanking interval.)

Tim L
TheHappyFriar wrote on 10/5/2007, 8:37 PM
has this been done before? I'm sure that the only reason it showed up now was because at the station things are rigged for digital but sent to both x-mitters.