I want to make my dvd's 6 hours like my vhs tapes.. ( I use them to help me sleep) how do I do this?
By getting you a DVD the size of a Frisbee.
Seriously, we are talking about apples vs. oranges here. It was possible to cram a lot of tape into a VHS cassette and set it to very low quality recording (SLP), but you have a lot less flexibility with a DVD disc. You can get a dual layer, but that is about your only option.
They make a DVD-18, and it holds twice the amount of a DVD-9, but you have to flip it over manually (and I have no idea where you would get one). But even that would not give you 6 hours of playing time. There is no way to vary the read speed of a DVD, ergo no way to extend how slowly it runs out the clock.
The only thing I can think of would be to see if you can still find quality VHS tapes and make copies for backup.
You can certainly cram 6 hours of video on a DVD, I do it all the time. The key is reducing the bit rate for the mpeg2 encoded video. The quality will suffer but it remains watchable and playable on DVD players. The easiest way is a DVD recorder/VHS combo. If you have video captured with "Rescue My Videotapes" you need to have a DVD authoring program that allows you to reduce the bit rate or offer a "fit to disc" function. If you have Magix Movie Edit you can reduce the bit rate before burning the disc. It appears that Magix allows you to encode a maximum of 4hrs 20 min but some others will allow more compression.Perhaps someone else here has an idea how to use Magix to compress the video even further. Here is an example of the 4h:20min setting in Magix:
Terrerad is absolutely right, although I really can't imagine what the vhs tape will look like once you drop the bit rate low enough to get 6 hours on a DVD. Especially if it was recorded in SLP! If it takes you 6 hours to fall asleep, you may want to consider a sleep aid either prescription or non-prescription. Although you have probably already tried that.