msvfw32 provides encode/decode video streams. Those DLLs only implement the proper switch between a caller and a driver providing the implementation of the requested format coding/decoding operation.
There's nothing specific in Wine implementation compared to Windows one. Here's however a list of the builtin decoding drivers:
Table 13-3. Wine VIDC drivers
|msrle32||Microsoft RLE (Run-Length encoded)|
|iccvid||Radius Cinepak Video Decoder|
Note that Wine also supports native video codecs as well.
All builtin VIDC drivers are 32-bit Unicode DLLs.