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Main => Monitor/Video Forum => Topic started by: Darq on September 24, 2007, 05:55:37 pm

Title: noob vga to a/v composite question
Post by: Darq on September 24, 2007, 05:55:37 pm

I know everyone will tell me to get a different video card but is there a way to convert a vga signal to a/v composite?  i.e. conversion cable?

Thanks

Title: Re: noob vga to a/v composite question
Post by: MonMotha on September 24, 2007, 07:02:09 pm

Said cable is a non-trival matter.  There are devices which exist, though they're generally larger than just "a cable", and they are usually somewhat expensive ($100-200 type range).  It would probably be cheaper and easier to just get a new video card.

The reason, if you care, is that a VGA 640x480 signal has twice as much data as a NTSC TV signal.  To convert, you have to interlace the VGA signal (take every other line, offset each frame), convert from RGB to YPbPr, then QAM modulate the chroma.  This takes hardware.  A video card with TV out already has this hardware and is produced in mass quantity hence cheaply.

Oh, the device you're looking for is commonly called a "scan converter", if you want to look one up.  Be aware that they vary wildly in quality.