video compression

After running out of space on my C, I identified the culprit as my little home project, specificity the test renderings weighing 30GB each... nothing little cleaning and few setting adjustment couldnt fix.

But that file size does raise the question, if i'll be able to fit my final work on a DVD. the problem is that I dont understand anything in video compression, so my question si simple which compression should I use:
or render it losslessly and use some other compression method, like this open source implementation of x.264 (which is claimed to be very good) ?!

H.264/MPEG-4 (AVC) is widely used (we use it for a videos shown on a local cable TV show).  I don't know what you're intending to do with it so speaking generally, using one that is commonly used by many others reduces the chance of compatibility issues.  Will it be aired?  Streamed over the 'net?

Wiki:
- Video Compression: http://en.wikipedia.org/wiki/Video_compression
- H.264/MPEG-4 (AVC) http://en.wikipedia.org/wiki/H.264/MPEG-4_AVC

While AVC is "tried and true," the BBC has developed VC-2 much more recently and I've heard people that know a lot more about this stuff talking about it.  I can't offer anything about it that you can't read about on wiki/using Google.  Personally, I would go with an industry standard rather than a promising new development, but that's just me (AVC vs. VC-2).

One of the reasons I chose R/W Blue Ray Disc over DVD or HD-DVD is because it has a larger capacity. 30GB will exceed a single side of a BRD by 5 GB uncompressed (BRD are 25GB per side, 50GB total); HD-DVD are 15/30 iirc.  I wanted a player to watch movies, but also needed the writer to burn copies of my roommate's self-made videos after editing.  The capacity issue was a deciding factor for me.

This wiki article shows quite a bit in a table about the characteristics of BRD and HD-DVD.  Maybe this will be useful.  Note that it lists AVC as a mandatory codec.  This is significant, as all players will be required to be able to play it.

HD Optical Disc formats comparison: http://en.wikipedia.org/wiki/Comparison_of_high_definition_optical_disc_formats

That all being said, I'm just a hobbyist and definitely no expert.  But if I were in your shoes, I'd probably just use AVC (and trim the final cut down so it fits on a single side of a BRD).

Aired? sounds fancy, unless you count my living room TV or my PC's there would be no much airing being done and definitely no steaming this monstrosity over the net, not because it would weigh to ton GB wise but because some anorectic think they weigh a ton   

But it's a good question, that I havent gave enough thought before, I'll need to check it further, since at the moment I am not sure that my old and cheap DVD support either  of those   I'll probably  finish the movie and go with the "tried and true" AVC pray and render, if not (space wise) i'll cut off on the quality/resolution or if it's wont be supported i'll choose the next format from that list, thanks.

MPEG-4 is your best bet since it's highly compressed and is virtually standard as far as the dvd industry goes. By 'Lossless' I'm assuming you mean no 'Compression'. However, 'Compression' in MPEG-4 refers to how whenever there is a picture which doesn't change, it doesn't add more frames of the same picture but instead have the frame and add an instruction to tell how many times to display the frame. Also with MPEG-4 it utilizes a way of doing the above, but with individual 'blocks'. Kind of splitting the screen and whichever 'blocks' don't change from frame to frame, they don't copy, only the parts which change from frame to frame have new pictures in each frame. Also I believe it includes a means of 'Tinting' a 'block' to the right colors instead of adding a new picture when things get brighter to conserve even more space but I could be wrong with that.

I don't know if this is the info you were looking for but hopefully it helped.

Lossless compression is different from lossey compression. Lossey compression actually reduces the quality of what the viewer sees (even if it's trivial). If MPEG-4 only removes duplicate frames/blocks whatever and doesn't mess with the content of the frames themselves, it's lossless compression.

Didn't realize I had a 'y' there, oops lol. Alright the OP did too but I think I get what he and/or she meant.