internal extern static double NativeMpg123GetEq(IntPtr handle, [MarshalAs(UnmanagedType.I4)] Mpg123.Channels channel, int band);
internal extern static Mpg123.Errors NativeMpg123Eq(IntPtr handle, [MarshalAs(UnmanagedType.I4)] Mpg123.Channels channel, int band, double val);