2 Small-ish AVI -> 1 Larger AVI = HUGE File. Why?

[cxp36]

Whenever I combine 2 or more .AVI files into one file, the size of the resulting file is always much, much larger than the sum of its parts, and I'm trying to find out why.

As an example, I combine 5 AVI chunks, each roughly 150MB, and end up with a 4.1GB file. The same thing happens if I combine 2 AVI files of about 600MB each - I still end up with a file that is around 4GB.

To join the video parts, I've used Nero Showtime, as well as Movavi Suite 5, with the same results. The video I'm combining is always different parts of the same video - that is, Homemovie1.avi, Homemovie2.avi, and so on. Different parts of the same source. Changing output quality from "Best" to "Normal" doesn't make a difference.

So why doesn't 600MB AVI + 600MB AVI = 1.2GB AVI? And, how can AVI files be combined without bloating to enormous size files?

Thanks for any help.

[guns1inger]

Use AVI Demux in Copy mode. Open the first file, then append the rest. If it asks you if you want to create timemaps or turn on smart rendering, say yes. Save you new file (remember to add .avi on the end of the name - AVI Demux doesn't do this) and you should have your new file.

All the other tools you have been using are re-encoding, and you don't seem to know how to set them up correctly.

If, however, you are converting for DVD, then expect the new files to be 3 - 4 times the size of the avi files if you want something like the original quality.

[Clevo89]

It must be a setting:

AVI (uncompressed) is 65Gig/hour

DV/AVI=30G/hour

What video properties are your original size and what properties are your finished video file?