Four Character Codes(FourCC) was introduced by Microsoft to clearly identify video data stream formats. The set of codecs that are four characters in length have unique values assigned to each format and pixel layout allows video frames to be passed between file and codecs by ensuring the FourCC of the source frame matches a supported codec.
When you play a media file the FourCC is identified and the registered codec for that type is brought into use. If that codec is a compression codec, the media file will be decompressed by the selected codec and played.
The simplest method of finding out a media files FourCC is by using a hex editor. Load the media file into the hex editor and search for the name of the FourCC
In the above example I have loaded a DivX3.11 alpha test file, this file uses the Microsoft Mpeg 4 codec, but has been modified by someone and called DivX 3. At this moment I don't know its DivX3.11 alpha. By looking at the code above you can see it shows the Fourcc as DIV3 by looking this up from a FourCC list you will be able to tell what codec is needed to play this file.
This list only shows the ones you may be interested in, FourCC codecs come out all the time, its never easy to put a full list of them together, but I will include one soon.
FourCC
Company
Comments
DIV3
DivX;)- MPEG4
Install, DivX 3.11 alpha, This is the slow motion codec, optimised for low motion source material. I hear that this codec is an illegal, hacked M$ MPEG4 V3 codec.
DIV4 DivX;)- MPEG4 Install, DivX 3.11 alpha, This is the fast motion codec, optimised for fast motion source material. Not used much, DIV3 produces higher quality, but now and then this also shows up in some AVI's
DIVX
DivX
Install, DivX 5, The DivX 4 is an open source codec, but since DivX version 5 the company is now charging for this codec, and has trademarked "DivX" DivX 5 can also be used to decode DivX 4 (OpenDivX) DivX 4.11, DivX 4.8
DX50 DivX Install, DivX 5, The now final version of the open source codec. The DivX company who now charge for this codec.
XVID
Xvid
Install, Xvid, When DivX 5 was released, a group of people continued the open source Project Mayo, and come up with this. DivX=Xvid backwards. So far this codec has given more problems than any of the others put together.
AP41
Angel Potion
Angel Potion, another illegal hacked version of the M$ Mpeg 4 codec, this one was supported by the SMR "Fake" movie company, its use resulted in most people complaining about violet coloured movies. You don't need the SMR Angel Potion codec at all !!!
MP42 Microsoft
Installed by Windows Media Tools, however with MP43 M$ don't want people using it to make AVI's, only ASF. V4.00.0.3688 of The Mpg4c32.dll contains all 3, and is apparently unlocked for AVI
MP43 Microsoft
MPG4 Microsoft
Not used much HFYU
Huffy
Not used at all for sharing, but has its uses for video capturing MJPG
Mjpeg
Another not used sharing, but has its use WMV1/2
MP43Microsoft
Not AVI, this codec is Microsoft's WMV it is the MP43 that is used to make the .ASF files which sometimes confuses people when ASF are renamed to AVI or AVI renamed to ASF/WMV You could use a hex editor to find out these things (vdub also has hex editor built in), however there are programs that are much more advanced for finding these details, and I recommend Gspot for this job
