Nowadays, the massive proliferation of real-world multimedia devices has paved the way to the emergence of a new paradigm called the Internet of Multimedia Things wherein Low-power and Lossy Networks (LLNs) are the main components of this new technology. RPL is an IPv6 routing protocol for LLNs designed by IETF to meet the requirements of a wide range of LLN applications such as Wireless Multimedia Sensor Networks where video traffic is expected to reach 6 times more than non-video traffic in 2025. The mono-instance version of RPL is far from satisfying the network-s Quality of Service (QoS) and the user-s Quality of Experience (QoE), as video in its compressed form is typically composed of various frames with different priorities requiring different QoS and QoE levels. In this paper, we exploit the multi-instance version of RPL for developing a new routing approach that improves the transport of a compressed video, composed of two types of frames with different priorities, by delivering each of them on the corresponding instance. The fundamental question we are addressing, is to find the best way to construct these instances: instances with Nodes Disjoint (ND) or Links Disjoint (LD). To do so, we designed a Multi-Instance routing protocol, named MI-RPL, and we performed extensive simulation experiments using the Cooja simulator. The comparison of MI-RPL-ND, MI-RPL-LD and RPL which regards to QoS and QoE performance metrics, confirms that multi-instance routing for video transmission in WMSN (and in particular MI-RPL-ND) is the best choice.