Power Macintosh: NTSC Video Out Choice & Menu Bar Missing

I have an NEC monitor connected to my Power Macintosh 8100 AV system with the monitor connected to the S-Video port. I have two options for 640x480; 640x480 (NTSC - TV only) & 640x480 (NTSC).

What is the difference?

I also have a Power Macintosh 8500 with 4 MB of Video RAM (VRAM), a Multisync 15 inch display, and a 27 inch television set. I am attempting to use the highest resolution (800x600) available for both the monitor and television set. I am mirroring the computer's monitor onto the television screen.

I cannot see the menu bar on the NEC display or the TV in either of these setups. What is wrong?
NTSC Options
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The reason that the S-Video output from your Power Macintosh 8100 to your NEC monitor allows you two choices at the same resolution is because of convolution.

The NTSC-TV selection provides convolution.

The NTSC selection does not provide convolution.

Using the NTSC-TV option will provide a raster with substantially less jitter than with the NTSC option.


Missing Menu Bar
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As far as not being able to see the menu bar is concerned, it is because you are in the overscan mode. Select a reduced resolution (underscan mode) and you will see the menu bar.

NTSC (S-Video) video output has different capabilities when compared to standard RGB display output. NTSC output on the Power Macintosh 8500 series computers only supports resolutions up to 640x480 output. In resolutions at 640x480 and above, the menu bar will disappear and the picture will appear to go off the sides of the screen. This is called overscan mode.

Apple does provide lower resolutions that better match the capabilities of NTSC. These are 512x384 and 320x240. Both resolutions will show the whole display area and the menu bar will not be cropped. This is because the conversion from RGB resolution to NTSC scan lines better match the capabilities of NTSC devices in these resolutions.

In fact, 320x240 is an excellent resolution to use for outputting QuickTime video. The computer can playback video faster at 320x240 resolution and the Power Macintosh 8500 series computer's hardware will optimize playback at 320 to fill an entire NTSC video screen.
Published Date: Feb 19, 2012