NTSC tv standard is 30 frames per second , Pal tv standard is 24 .
You will get a flicker free display at 16-18 fps depending on the person viewing.

There are some complex issues mainly to do with the tv used to view them . Computer monitor has the same issue but the frame rates are different. 1280 x 720 is HDTV .

You might get some ideas from www.videohelp.com

If you are streaming video the compression and bandwidth required are important factors. You need to set it so the available bandwidth will be greater than required by the video. Dialup users rarely get a smooth streaming video.