Re: This can't be true...

[scott@alfter.diespammersdie.us (Scott Alfter)]

-----BEGIN PGP SIGNED MESSAGE-----
Hash: SHA1

In article <cPSdnaLkLJAqUtDZnZ2dnUVZ_sednZ2d@comcast.com>,
Michael J. Mahon <mjmahon@aol.com> wrote:
>As the generation of spec-perfect NTSC timing and sync has become a
>piece of cake (or a tiny sliver of silicon), the sloppy NTSC of the
>early days has become rarer, so modern equipment is likely to be more
>dependent on precise timing.

Indeed.  At work, I'm modifying the ivtv driver (a Linux driver for MPEG-2
compression boards based on the Conexant CX23416/CX23415) to work with a
four-input card we've built.  Another chip on the card, the Conexant
CX25836, captures the video and feeds it to a CX23416 for compression.  If
you feed the card video that isn't right at 29.97 fps, it doesn't sync up
properly.

For recording from TV, this isn't a problem.  Security cameras, OTOH,
frequenly are synced to utility power and end up running at 30 fps instead
of 29.97 fps.  They do this so that a cheap switch can cut from one camera
to another without having the image roll around until it syncs up again.  It
wreaks havoc with this capture card, though (and others like it...I first
observed this problem with a Hauppauge WinTV PVR-150). 

At some point in the not-too-distant future, I'm going to have to go up to
each of our outdoor cameras on a cherry-picker to set them to 29.97 fps.

  _/_
 / v \ Scott Alfter (remove the obvious to send mail)
(IIGS( http://alfter.us/            Top-posting!
 \_^_/ rm -rf /bin/laden            >What's the most annoying thing on Usenet?

-----BEGIN PGP SIGNATURE-----
Version: GnuPG v1.4.2.2 (GNU/Linux)

iD8DBQFETnRoVgTKos01OwkRAkMAAKD3u3NvfwwJhtg2eWwmBkEi5D+OKwCgw13l
075DfeYNRmZoABlI2pXfMN8=
=KERm
-----END PGP SIGNATURE-----