This paper proposes a novel cross-layer packet prioritization scheme that overcomes the limitations of conventional video prioritization schemes for IPTV system. In the conventional schemes, the Extend profile or frame unit is used for prioritization and these incur limited uses of the video prioritization schemes or unreliable transmission of the P-frame and B-frame headers. In order to overcome these limitations, the proposed scheme uses the MPEG-2 system information and the H.264/AVC NAL header information to prioritize the important video packets including the P-frame and B-frame headers. The experimental results using a testbed demonstrated that the proposed scheme has a significant performance enhancement over the conventional video prioritization schemes in terms of packet utilization ratio for video streaming, direct frame loss ratio, and PSNR.
Although the latest video codecs such as H.264/AVC, H.264/SVC, and VP8 were developed with network-friendly features, provisioning the quality of video delivery over IEEE 802.11 wireless networks is still challenging because of errorprone medium and random access. This paper evaluates the quality of video delivery using those latest video codecs over IEEE 802.11. Our results show that reduction of coded video data, consideration of the queue size of each Access Category, and the mandatory implementation of error recovery features in H.264/SVC can help provide robust multimedia transmission over IEEE 802.11. In addition, the performance of the latest video codecs is compared via extensive simulation scenarios. Our comparison shows that VP8 achieves good video quality with the basic medium access control techniques of IEEE 802.11, whereas H.264/AVC and H.264/SVC benefit significantly from appropriate mapping schemes between encoded video fragments and IEEE 802.11e Access Categories.
The recent proliferation of mobile devices increases the demand for high-quality real-time video services in wireless network. However, the characteristics of wireless medium such as interferences and ease of congestion make it difficult for the delivered video to be played out in a timely manner.The latency introducedby those wireless characteristics severely degrades the perceptual quality of real-time videodue to intermittent playoutat the client side. In this paper, we propose adelay-constrained adaptive early drop scheme for real-time video delivery over IEEE 802.11 wireless networks. In our scheme, an intermediate router forcibly discards the less important video packetswhich are expected not to be played out in time. The simulation results demonstratethat the proposed scheme can achieve 20% lower endto-end delay and60% less frame loss ratio with32% better Peak Signal-to-Noise Ratio (PSNR) compared to the existing crosslayer mapping schemes.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.