In this article, we address the problem of how to make the wireless device-to-device (D2D) video multicast systems have better quality provision with consideration of internet-of-things (IoT) applications. We propose an opportunistic transmission and fair resource allocation framework, including joint application-layer and physical-layer transmission and optimization. First, we use a parallel subchannels structure by concatenating the Fountain codes and diversity-embedded space-time block codes to provide reliable and flexible transmission in heterogeneous circumstances. Second, we exploit the quality of heterogeneous user experience (quality of experience) metric under D2D video multicast systems, with consideration of various channel states, device capability, video content urgency, and the number of demanding users. Third, we formulate reliable multiple video streams broadcasting to heterogeneous devices as an aggregate maximum utility achieving problem, and we use opportunistic scheduling to select suitable users in each transmission interval to improve the broadcasting utility. Fourth, we use the utility fair scheme to guide rate allocation among multicontent video multicast. Extensive performance comparison and analysis are presented to demonstrate efficiency of the proposed solution.