public static extern double mpg123_geteq(IntPtr mh, mpg123_channels channel, int band);
public static extern int mpg123_eq(IntPtr mh, mpg123_channels channel, int band, double val);
[DllImport(Mpg123Dll)] public static extern double mpg123_geteq(IntPtr mh, mpg123_channels channel, int band);
[DllImport(Mpg123Dll)] public static extern int mpg123_eq(IntPtr mh, mpg123_channels channel, int band, double val);