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Some more details about files you want to burn are needed, and also about your standalone player.
Rewritable media (i.e. the RW discs) are not reliable in the long term, so if these data you want to burn on discs are important for you it is better to use write once discs, and not RW media. It is very important, moreover, that you buy quality discs, because all “el cheapo” discs will become unreadable in a short time. Remember that the quality of the disc is one of the most important factors to avoid data loss.
Regarding the movies, are these AVI or DVD or other? Is your standalone player able to read avi movies or these must be converted first into DVD format?
These are important questions, because a 700MB AVI movie, for example, will become a 2 GB file once converted into DVD format (dimensions are only an example, it is related on parameters you’ll select for the conversion, but the principle is that an avi movie converted into DVD format will ALWAYS have files with larger size than the original AVI.) Consequently, if you must convert AVI into DVD first, you’ll need a higher number of discs to burn all these data.
The conversion part can be done with many software (some are also free), but it requires a high computer power because these conversions needs a lot of calculations. If your CPU is not powerful enough, it could be necessary to wait for many hours (even 24 or more) to complete a single conversion.
If you have many conversions to do, maybe the easiest solution is to buy a standalone player already able to read AVI files, so you can burn files directly on a DVD and watch them in your television. These players can be easily found also at low prices in these days
Actually, there is an easier alternative: buying a standalone player able to read avi movies and provided with an USB port. In this way you can connect to the USB port an hard disk and you don’t need to burn files on a disc at all