How to know exactly the codec of a video file?

[zyzrbcb]

Hi all,
I have some questions below.
1, I can get the fourcc code of .avi format file by "Gspot",I can also change the fourcc code by "AVI FourCC Changer" ,then how can I know exactly the fourcc code and video codec of .avi format file?What about .mp4 format and other format file?
2, Where to find the codecs below?and how to use them to make .avi or other format files?

FourCC / 4CC Codec List
3IV1, 3IV2, 3IVD, 3VID
DIV3, DIV4
DIVX, DX50
MP4V
M4CC
FVFW
MPG4, MP42, MP43, M4S2
NDIG
PVMM
SEDG
RMP4

Thanks!

[foxyshadis]

Try fourcc.org. If you only need a decoder, ffdshow handles most of those, mplayer handles a couple more.
1, I can get the fourcc code of .avi format file by "Gspot",I can also change the fourcc code by "AVI FourCC Changer" ,then how can I know exactly the fourcc code and video codec of .avi format file?
If you change it you change it. The fourcc is whatever you've changed it to, even if it doesn't match what's actually in the video (and will likely crash the decoder). 3IVD, DIVX, DX50, XVID, MP4V, are interchangable.

For mp4, mkv, etc, try MediaInfo instead of gspot. (Works on avi too.) Or the latest alpha of gspot 2.60.