There are not so many videos available on Hindustani Shastriya Sangeet and they are not so easy to find.
First come the VHS tapes, the oldest support. Nowadays we have DVD and VCD - a lesser known format which I call "DVD of the poor". VCD means Video Compact Disc. It is more compressed than DVD - therefore giving a lesser quality than the former. It uses the same support as an audio CD or CD Rom (650MB or 700MB) instead of the 4,7GB of the single side/single layer current DVD, and is readable by Macs, PC and by most of today's DVD players.
Since 1987, I regularly purchased through the web, computer hardware, software, and plenty of miscellaneous items and never got cheated. These companies do deliver the goods. Therefore, you could order them on the web - by making a secured payment with your Visa card - and should be safe.
Most of Alurkar Music House videos (in NTSC or PAL) format may be purchased at Khazana's. Ali Akbar Khan's ones at his school address.
Here is a non-exhaustive list of videos you could get for the pleasure of your ears and eyes... even if VHS are very often of bad image quality - probably due to unadequate duplicating material and abusive use of long cross-dissolve transitions... an angel flies by !