With the approach of InSight to Mars today, and the two cubesats watching it, much is being made about seeing "Live Video" from the cubesats. I'm pretty sure that simply can't happen, but I'm wondering if the technology to broadcast live video actually exists, if there was a camcorder on one of the missions already at Mars. Could live video be transmitted (IE, is there a capability to get the required bandwidth at a distance of Mars), and received on Earth in a legible format (After speed of light transmission delays, of course)
If not, then what would it take to make this actually happen?