Hi all,

I have captured a VHS tape using Virtualdub (v1.3c) using MJPEG compression.
This has resulted in an AVI file of approx 60gb. I then wanted to split the
AVI file down into 3 seperate sections (3 episodes on the VHS tape) using
the job control mode of virtualdub. The first section was ok but kept
crashing on subsequent sections. I then found that there is a much newer
version of virtualdub available (v1.5.4) which I downloaded and tried again.
This time the remaining 2 sections worked fine but I have a query.

The first section (using VD 1.3c) has a file size of 17gb for 27mins of
video. The other 2 sections (using VD v1.5.4) are only 4.9gb & 4.3gb for
27mins of video. If I check the properties of the 3 files, everything is the
same except the video data rate. For section 1 the datarate is 722kbps for
section 2 it is 425kbps and section 3 is 127kbps. All were using the same
MJPEG compression codec with the same settings, same resolution and same
frame rate. Also all were using the dynamic noise reduction filter in
Virtualdub.

Does anyone know why this should be. I don't know what effect the datarate
has on quality. Should I be worried about this much lower datarate or just
be pleased with the smaller filesize.

Many thanks

Russell Spearing
Portsmouth, UK