#69 Add basic support for DirectShow Base class (for gstreamer dshowdecwrapper)

[Frédéric Wang]

The dshowdecwrapper plugin was recently ported to GStreamer 1.0 and allows to use native Windows decoder (MP3, WMA etc). However, it can not be built with MinGW-w64 for lack of DirectShow Base Classes support:

https://bugzilla.gnome.org/show_bug.cgi?id=677223#c3

The missing header is <streams.h>, which includes many other headers but probably only a subset of the declarations is needed for dshowdecwrapper (it seems that only the following classe sare enough: CBaseFilter, CBaseOutputPin, CBasePin, CBaseRenderer, CCritSec, CMediaType, CSource).

https://msdn.microsoft.com/en-us/library/windows/desktop/dd318195%28v=vs.85%29.aspx

What would be the proper to add these declarations into MinGW-w64? Just reading the msdn doc and writing header files?

[Frédéric Wang]

Work-in-progress patch.

[Frédéric Wang]

Patch V2

[Alex Agranovsky]

Would it be possible to include fourcc.h as well?