How to create a direct show filter for vp9 video deocder

Question

I am new to Direct show. I have an C solution of vp9 decoder and want to create an direct show filter which can decode and play my compressed file.

Can some body please help me on how to add these filters to the Direct show which allows me to decode my encoded file with simple simple GUI of play, pause and run.

Should my decoder application should be in exe or dll type ?

Any materials regarding adding\registering the custom codec to Direct Show will be greatly appreciated.

Thanks in advance for helping me out.

Answer 1

The DirectShow filter for VP9 already exists, so you could just look at the source code — https://chromium.googlesource.com/webm/webmdshow/

Answer 2

Generally in DirectShow codecs are transform filters. You can find samples of such filters in the Windows SDK (/Samples/Multimedia/DirectShow/Filters/), look at EZRGB24, for example. They are usually compiled as dynamically linked libraries to files with ".ax" extension (but this is just a DLL really). See CTransformFilter base class and surrounding articles in DirectShow documentation.