Newbie: cut out bit with VirtualDub has lower bitrate

[:-Daan]

Hi! Nice website this is. Helps me a lot. Still there is something I don't understand.

I used a guide from this site (www.videohelp.com/virtualdubedit.htm) that "explains how to cut a DivX without reconverting it" to cut out a short bit of a DivX avi. Instead of VirtualDub, I used VirtualDubMod 1.5.10. I used Direct stream copy (as it says in the guide).

However, when I use AVIcodec to examen the original file and the short bit I cut out, I am told that the original has a much higher bitrate.

Why is that? Doesn't mean "without reconverting it" that the bitrate should remain the same?

Here's what AVIcodec tells me about the original:

Bestand : 700 Mb (700 Mb), duur 0:48:34, type AVI, 1 audio spoor(sporen), kwaliteit 86 %
Video : 633 Mb, 1824 Kbps, 25.0 fps, res. 688*384 (16:9), DX50 = DivXNetworks Divx v5, Ondersteund

and the short bit:

Bestand : 1.18 Mb (1.18 Mb), duur 0:00:10, type AVI, 1 audio spoor(sporen), kwaliteit 65 %
Video : 962 Kb, 788 Kbps, 25.0 fps, res. 688*384 (16:9), DX50 = DivXNetworks Divx v5, Ondersteund,

where bestand = file, duur = duration, spoor = track, kwaliteit = quality and ondersteund = supported.

[:-Daan]

I found a possible answer to my question in a post by phearon at the virtualdub forum (http://forums.virtualdub.org/index.php?act=ST&f=2&t=8843&hl=&s=63787cafc190a8b9ec73598d32d57d9c):

"It's not unusual for the bitrate to change, since the bitrate of the video stream isn't perfectly even throughout the file. Usually, constant bitrate (CBR) encoding simply means the bitrate is constant over a narrow range. This is sometimes known as average bitrate (ABR) as well. If your file is variable bitrate (VBR) encoded, then the bitrate may vary wildly within a local area. The bitrate reported is usually the actual bitrate of the stream and not the bitrate setting it was encoded with."

Since the bit I cut out has very little movement in it, it makes sense that it has a much lower bitrate than the overall bitrate of the original.