As you already know (I think) DV AVI is 13GB per hour. So... if you are rendering to DV AVI... then count on 13GB per hour.
If you are rendering to MPEG2 - then the size is dependant on the bit-rate settings you choose. With the default DVDA NTSC template you will get around 1 hour of video in 4.3GB (or thereabouts).
With other formats (such as Windows Media) the size again is totally tied to the bit-rate....
Rendering basicly means to transcode one file type to another,or when apply effects to a clips they have to be encoded into the original image. this is why when you apply an effect or a bunch of effects to a clip that its playback rate slows down.
Bit,
We have no problem answering your questions, but I would also suggest you pick up a copy of Spots book, I dont know about the Vegas 5-6 books , but I know you can find a copy of the Vegas 4 book.
Much of what it covers will apply to most things in Vegas versions and he give excelent info on all the Basics.
I keep it on hand as reference material and go back to it frequently.
Just a reccomendation if you plan on using Vegas alot its a valuable tool.
Video is a fascinating animal. It's made up of a whole bunch of dots or pixels. Each snapshot has 480 rows with 720 pixels in each row, and there are 30 such snapshots every second (I'm talking about video in NTSC countries like the US). Now consider that each of those dots needs to be able to represent any color, so we need 3 bytes of data for each dot (one byte for red, green, and blue values).
Do the math and you realize that video can create enormous files after just a few seconds. So people have invented clever ways of discarding unnecessary data in order to make the video file smaller. The "DV" format reduces the bitrate down to about 4MB/sec. The "MPEG2" goes even further, down to about 0.5-1MB/sec. The process of converting from one format to another is called "rendering." Rendering can happen realtime (at the same rate as the video itself), or can take 10 or even 100 times longer, depending on hundreds of factors.
The current common state-of-the-art in compression is probably represented by H264, which compresses video to about 1/3 the space used by MPEG2. This means the raw video image can be compressed by a factor of about 200:1 without losing much visual information perceived by the human eye. Remarkable.