Just about any DVD player will play them.You need to check the specs to see if the DVD player will play dvd+r and dvd+r DL.

dont know about double layer but i use to have a camcorder that only recorded in +R and the camera documentation claimed that any (USA) DVD player would play the disks

I cannot imagine the industry abandoning compatibility for the single layer at least without the hoopla they used for blue-ray (without all that hype blue-ray would have died long ago)

but it is real easy to be sure.... when you go to buy your next dvd player.... first burn 8 gig of home movies on a +R DL disk and take it with you.... if you cannot scan through all the videos dont buy the machine

Your computer