Can someone explain the codecs found using a utility called GSpot?

[Rooster6975]

There is an AVI informational tool called GSpot available for download on divx-digest.com

http://www.divx-digest.com/software/gspot.html

I use it to determine what the audio stream is on any particular AVI file (ie. MP3 and what bitrate, AC3, etc...). It makes it very easy to ensure you have the correct codec.

It can also verify if you have the correct video codec installed, provide you a list of installed codecs, and contains a list of over 200 different codecs which may exist in AVI files.

When I run the option, "Video Codecs installed on this machine", it comes back with some information which I find confusing.

There are 4 columns :
FourCC, Codec Installed name (from OS), Description (GSpot), and Vendor (GSpot). If you look in the list for the DivX codecs, you will find the following (there are 4 columns, each under one of the headings listed above) :

4CC - Codec from OS - Description -Vendor

DIV3 - DiVX MPEG4 Lowmotion - DivX3 lowmotion - DivX
DIV4 - DiVX MPEG4 Fastmotion - DivX3 fastmotion - DivX
DIVX - DivX Pro 5.02 codec - DivX 4 (OpenDivX) - ProjectMayo

Why is DivX4 described as Divx3 Fast-Motion? Why is DivX 5.02 described as DivX4 (OpenDivX) ?

I want to be able to reliably tell which codec was used to produce what AVI. I am afraid that I find the above info confusing. Can someone clarify what I am seeing?

Thanks,
Rooster

[Rooster6975]

The answer....

In summary,

Divx3.11a was an illegal hack based on the MS codec. Any divx created with this codec will come up in Gspot as either low-motion or fast-motion divx3 depending on which was used.

Divx4 actually has nothing to do with divx3 and is a completely legal tool that is offered by OpenDivX.
Divx5 is the successor to DivX4. The next version with more advanced options. Both Divx4 and Divx5 will come up in Gspot as DivX4 (OpenDivX) as that is the base of both of these codecs.

For those others whom have posted in reference to the JUNK CHUNK fields within the RIFF info (in GSpot), these are blank fields where people can record information such as what was tool was used to encode the AVI file. It does not denote corruption of any sort, it is merely a placeholder for textual information.