method... as pointed out earlier, it does not need to be high definition on a "normal" single layer or double layer disc. Even video captured as high definition but downsampled to standard definition is very crisp as compared to the standard definition-only days.
But since we do not know your environment - nor that of the grandparents to which you refer - it is a bit of a challenge.
As I recall "the old days" of sharing video with others, I would connect the camcorder to a VHS deck and copy the contents of the camcorder video to the tape in the deck. I don't remember sending the one and only original copy of video anywhere. No, or very limited, editing. Now that we can edit, add transitions, credits, special effects and audio, home movies can be lots more fun - whether high definition or standard definition.
There are different ways to get different formats of video to others.
1) You *could* do the same today as in the "old days" - There are lots of VHS decks still available. The copy will not be in high definition. Can you keep using your existing camcorder? Yes.
2) You *could* get a DVD recorder. Essentially the same as the VHS copy, but on disc.
The copy will not be in high definition. Can you keep using your existing camcorder? Yes.
Both of these options are for standard definition only, so I expect you are not interested... but for completeness, I included them.
3) You *could* get a BluRay burner
This means the person with whom you are sharing has a method to play what you burn
and it is properly connected to a HDTV. The copy will be in high definition only if you recorded in high definition and output as high definition to the BluRay disc. A high definition camcorder would be needed.
4) You *could* save the edited high definition video files back to the camcorder - if the camcorder is miniDV tape based - and send that miniDV tape to the person with whom you are sharing... In order for them to view the video, use of HDV miniDV tape based camcorder or a HDV deck properly connected to a HDTV is required. A high definition camcorder would be needed to capture HDV.
5) You *could* save the edited high definition video files as video saved at "full quality" and burn to a data DVD as a data file - not as a video (VOB or VRO) file. Because high definition video uses so much room, only a few minutes will fit on a double sided (8.5 gig) "normal" DVD. This disc would then be played back using a computer with a current (fast) CPU and an optical drive capable of reading the DVD data disc. The data file would likely be QuickTime or .AVI. If the recipient has an AppleTV or other "media center" device capable of high definition file use, that would normally be connected to a HDTV... Or if the computer with the appropriate CPU and optical drive is connected via VGA (my Panasonic plasma has a VGA port), then it can be the playback computer.
5a) Rather than using a disc, you *could* copy the data file to a memory card or other external storage device. A double layer DVD can hold up to 8.5 gig; but there are memory cards and thumb drives
that can hold more. Or even an external drive would work - and those come in terabyte sizes. When the folks are done watching, they just send the card/drive back for the next videos to be copied.
6) You *could* upload the finished project video to sites like vimeo.com and computer playback at 720p high definition is possible. Connectivity of the computer to a HDTV (as indicated above in example 4) would be helpful. In addition to this, you *could* have your own 1080i/p storage site for sharing HDV for streaming or download in case you can't find one.
7) You *could* upload the finished project video to sites like YouSendIt.com and have the recipient download the video for playback on computer (perhaps with connectivity to a HDTV)... If the recipient does not live closeby, this would likely be much faster than mailing a disc - if speed is a requirement.
So... you CAN create high definition video on a disc - but perhaps there is no need to. Just as in the past, where the recipient needed compatible equipment, they would need compatible equipment today. Optical discs are not the only method for sharing video; DVDs can be used a data storage devices - not just for sticking in a DVD for playback.