vidc.vivo=ivvideo.dll
msacm.vivog723=vivog723.acm

in Windows XP, 2000 and NT the entries for the codecs are not found in SYSTEM.INI but, instead, are in the registry under:
HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows NT\CurrentVersion\drivers.desc
HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows NT\CurrentVersion\Drivers32


System\CurrentControlSet\control\MediaResources\icm\vidc.vivo
Driver=ivvideo.dll
FriendlyName=Vivo H.263 Video CODEC Version 2.0.0
Description=Vivo H.263 Video CODEC Version 2.0.0

SOFTWARE\Classes\CLSID\{6DF271C1-AC6F-11d0-AC68-00AA00BF35C4}\InProcServer32
(default)=C:\WINDOWS\SYSTEM\ivvideo.dll

SOFTWARE\Classes\CLSID\{6DF271C0-AC6F-11d0-AC68-00AA00BF35C4}\InProcServer32
(default)=C:\WINDOWS\SYSTEM\vivog723.acm

SOFTWARE\Classes\CLSID\{B9F77840-2DC7-11D1-9B67-006097BA977C}\InprocServer32
(default)=C:\WINDOWS\SYSTEM\VVVIDFLT.AX
ThreadingModel=Both
