I recently purchased a multi-region DVD player (Sindave DVD-S188) and am generally pleased with it, except for the fact that it insists on playing "fullscreen" DVDs (such as older TV shows in a 4:3 aspect ratio) in a "stretched" 16:9 ratio. I've tried adjusting the display in the setup menu to 4:3, but nothing seems to work. Is anyone familiar with this model or do they know of any tricks/techniques I'm missing?

Adjust the aspect ratio of your TV to 4:3 when watching that content.

Cheaper players generally don't properly convert 4x3 images properly for 16x9 viewing- a 16x9 image with black side bars. If it upscales to 1080p, set the output to 480 and if your display is able to read the automatic format flags it can change using that. I had a DVD recorder that's since died that stretched everything when set to 1080, but when set to 480 it displayed everything properly.

Thanks everyone... working fine now!