gst::ffi::GstVideoFormatPack

type GstVideoFormatPack = Option<extern fn(info: *const GstVideoFormatInfo, flags: GstVideoPackFlags, src: gpointer, sstride: gint, data: *mut gpointer, stride: *mut gint, chroma_site: GstVideoChromaSite, y: gint, width: gint)>;