What is a upright low impact aerobics video?

I want to start some aerobics in my home at my convienence. I don't want anything that will be complicated on my knees, but will still be effective contained by weight loss. Any suggestions?What is a upright low impact aerobics video?
Debbie Rocker's Walking for Weight Loss
" An easy-to-follow, walking-style workout that vary the tempo and movements to maximize results (and minimize boredom). This program gently builds contained by intensity while constantly rotating the speeds and fat-burning techniques (e.g. pumping arms, superior knee lifts). Anyone can do these super-basic moves - simple march, lateral steps, lunges and heel taps."
None.
I use Turbo Jam and within each workout in that is at least one soul who does the entire workout low impact. I don't do them low impact, but I do love the workouts -- they're fun!
I don't know of any that are specifically low impact though. Sorry!
Good luck!
OK, this is going to sound lately awful but... if you look on amazon there are tape made for heavy set associates that are low impact. Another is *shudder* Richard Simmons series. I used to do those back contained by the day and they conspicuously work! Just close the blinds first (testify!) :)