Decode with offset is broken

[ajbadaj]

In this section:

H264Sharp/H264Sharp/H264Decoder.cs

Lines 188 to 190 in 26d9442

	fixed (byte* P = &encoded[offset])
	{
	int success = native.DecodeAsYUV(decoder, ref P[offset], count, noDelay, ref state_, ref yuv);

There is both:
byte* P = &encoded[offset]

and then using that below:
native.DecodeAsYUV(decoder, ref P[offset], ...

Causing a sort of double offset.

This means if you have an array that is needs to offset, you're forced to do a copy to avoid using Decode with an offset. For instance if I have a byte array of size 800, and the first 8 bytes are some other part of the stream, I have to slice and copy from 8 to length - 8 to pass into decode to avoid this issue, because effectively decode will try to work with bytes 16 to length + 8 causing the encoder to fail.