(a). What's d difference between

1. DVD+R
2. DVD-R
3. DVD+- R (Plus or minus)
4 and CD also..


(b). How is "Blu-ray DVD" capacity possible ?


(c). Wat's MP4 and 4GP?

A DVD+R is a Read-Only format of DVD supported by the DVD Forum
A DVD-R is a Read-Only format of DVD supported by the DVD+RW Alliance

They are just different formats of DVD with slightly different capacities

You cannot get DVD+-Rs, but you can get DVD+-R Drives, which can read both of the above DVDs

A CD just has a much lower data density due to the lower technology that was around when they were invented.
DVD is just higher capacity due to different format and higher density due to the better technology for reading.

Blu-ray DVDs use the same kind of technology as a DVD, but they use blue light to read the disc rather than red. Blue light has a smaller wavelength and so can resolve smaller details on a disc. This enables you to have an even higher density.

MP4 is a way of encoding audio or video files to decrease file size while still keeping good quality

I can't find details on 4gp and haven't heard of it myself. Maybe you meant 3gp? Which is a format that 3G use for video on their phones.

DVD +/- are competing formats of DVD recording. The differences are slight and not really meaningful. I believe + is slightly better for video and - slightly better for data.

Most drives, can use either format, so its not a major concern.

CDs are one format, but 2 types. R disks are write once and RW are rewriteable (that applies to DVDs too).

Go to Bluray.com for info on how it works.

MP4 is a file format for video files. not sure what 4GP is.