I was wondering what program or method is the best for archiving video. More specifically, I was wondering is it even worth using programs like winrar or 7.zip and compressing videos to try and fit more on a dvd for the purpose of archiving? I had a batch of 26 or so episodes that were about 170Mb each and used 7.zips most powerful compression setting to try and batch them into one zip file, and it only reduced it by about 2mb. 7.zip also has a bunch of settings on top of the "ultra compression" setting that I didn't mess with because I have no clue what they do. Might those settings make a difference? Is there a more specified program for this task? Or is compressing like this just a waste of time?
Compression does reduce the amount of data by small amounts but it also increases the risk of data loss. That is because more information is included in a block, and if there is a flaw on the disc or an error--and there will be in time: all discs begin to see increases in errors within days of the initial recording, although the increases are very slow and very small for good recordings/discs--that section might not be retrieved. Error correction uses some redundancy and interleaving methods to recover data. Some compression works by reducing redundancy. As you can see, you get little back by compressing the data, but you have increased the risk of losing it later on.
If you had 170MB of text documents and such, then you could considerably reduce the size using a rar/zip archive. It doesn't work with video files, which are already a compressed format. The only way to "compress" and reduce the size of the video considerably is by throwing away some of the data(reduce some of the quality) by using a codec-Divx/Xvid, x/H.264...Depends on how much you "compress", the quality loss might or might not be considerably noticeable.