NanDub and Direct Stream Processing...Why does a file get smaller if I just save it?

[Ronstang]

I was using NanDub to try and make a Divx file fit on 1 CD. I trimmed the credits and the file reduced in size by about 29 megs when I only needed a 16 meg reduction. So I decided to try and see how much of the credits I could actually keep. I kept cropping less and less and the file didn't grow too much. Finally I just Selected the whole original file and saved it.....BOOM...18 meg reduction in size without cropping a frame!

What is going on here? What is happening to make the file smaller than the original if I am simply saving the file again with no processing? I could understand a few 100 bytes difference but not 18 Megs!!!!

I am new to all this so I would just like to learn what is happening here. I also would like to know what kind of quality I am sacrificing by doing this. Just trimming the credits seemed logical.....but what kind of transformation is taking place here?

Thanks in advance for any help that is forthcoming.

Ron

[Ronstang]

OK.....test #2

Tried it with a different file....and the size was exactly the same after saving in NanaDub as the source.....?????

Now I really don't know.....

[UncasMS]

me neither

[khp]

Re: NanDub and Direct Stream Processing...Why does a file get smaller if I just save

Originally posted by Ronstang

What is going on here? What is happening to make the file smaller than the original if I am simply saving the file again with no processing? I could understand a few 100 bytes difference but not 18 Megs!!!!

I would suggest that you check the files with virtualdub's file information window. And use that to compare the smaller file with the original.

Do you know which tool encoded the original avi file ?.