New Post: How to decode OGG to Wav from byte array properly?

Three options:

1. Wrap the byte data in a MemoryStream: var oggStream = new MemoryStream(oggData);
2. Change the custom file format reader to return a stream that reads data as needed (preferred)
3. Implement NVorbis.IPacketProvider in the custom file format reader (advanced)
   

In all cases, you pass the stream / instance into the NVorbis.VorbisReader constructor and call ReadSamples to decode from there. The decoded data is 32-bit float PCM, and can be played by most audio libraries without further processing.

If you want to try option # 3, I have further comments. It is probably unnecessary, but since you are writing your own file format there is the possibility.