Beispiel #1
0
// Start streaming process
func (w *Webcam) StartStreaming() error {

	buf_count := C.uint32_t(256)

	res, err := C.mmapRequestBuffers(C.int(w.fd), &buf_count)
	if res < 0 {
		return err
	}

	if uint32(buf_count) < 2 {
		return errors.New("Insufficient buffer memory")
	}

	w.buffers = make([]buffer, uint32(buf_count))

	for index, buf := range w.buffers {
		var length C.uint32_t
		var start unsafe.Pointer

		res, err := C.mmapQueryBuffer(C.int(w.fd), C.uint32_t(index), &length, &start)

		if res < 0 {
			if err != nil {
				return err
			} else {
				return errors.New("Failed to map memory")
			}
		}

		buf.start = start
		buf.length = uint32(length)
		w.buffers[index] = buf
	}

	for index, _ := range w.buffers {
		res, err = C.mmapEnqueueBuffer(C.int(w.fd), C.uint32_t(index))
		if res < 0 {
			return errors.New("Failed to enqueue buffer")
		}
	}

	res, err = C.startStreaming(C.int(w.fd))
	if res < 0 {
		return err
	}

	return nil
}
Beispiel #2
0
// Read a single frame from the webcam
// If frame cannot be read at the moment
// function will return empty array
func (w *Webcam) ReadFrame() ([]byte, error) {
	var index C.uint32_t
	var length C.uint32_t
	res, err := C.mmapDequeueBuffer(C.int(w.fd), &index, &length)

	if res < 0 {
		return nil, err
	} else if res > 0 {
		return nil, nil
	}

	buffer := w.buffers[int(index)]
	result := C.GoBytes(buffer.start, C.int(length))

	res, err = C.mmapEnqueueBuffer(C.int(w.fd), index)

	if res < 0 {
		return result, err
	} else {
		return result, nil
	}
}