How to iterate over a double array in Cgo

double_array.go

package avformat

//#cgo pkg-config: libavformat
//#include <libavformat/avformat.h>
import "C"
import (
	"unsafe"
)

//https://www.ffmpeg.org/doxygen/2.7/structAVFormatContext.html
func (ctxt *Context) Streams(i uint) *Stream {
	offset := (unsafe.Sizeof(unsafe.Pointer(*ctxt.streams)) * uintptr(i))
	return *(** Stream)(unsafe.Pointer(uintptr(unsafe.Pointer(ctxt.streams)) + offset ))
}