Perceptual quality feedback based progressive frame-level refreshing for robust video communication
ABSTRACT In this paper, we propose an encoder side error resilience technique, namely the progressive group of picture (PGOP), which is well suited for rate controlled real-time video transmission over wireless channels. The PGOP scheme can be seen as an alternative approach to the group of picture (GOP) that periodically uses intra-frames (I-frames) for low bit-rate channels. This is because: (1) the PGOP scheme is shown to completely stop error propagation in a timely manner; (2) the PGOP scheme avoids the bit rate fluctuation problem associated with I-frames by using a progressive intra-updating scheme. We use the PGOP scheme in a perceptual quality feedback framework, and apply a novel online algorithm that helps shape the bit rate and explores the maximum recovery capability of PGOP. The performance of our scheme is demonstrated in a wireless LAN environment.
Full-textDOI: · Available from: Magda El Zarki, Mar 17, 2014
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ABSTRACT: This paper focuses on the design of the cross layer between the video application layer and the MIMO physical layer. MIMO physical layer research has promised an enormous increase in the capacity of wireless communication systems. Also MIMO wireless systems operate under fading conditions where the channel faces arbitrary fluctuations. Since the wireless channel changes over each coherence period, the capacity of the wireless channel, given the power constraints, changes. Hence to make efficient use of the available capacity one needs to adapt the video bit rate. However it is impossible to adapt at the application layer as changing the parameters of the video takes more time than the coherence period of the channel. In this paper we address this problem through a novel solution and also investigate its performance through a simulation study.Journal of Zhejiang University - Science A: Applied Physics & Engineering 09/2006; 7(10):1690-1694. DOI:10.1631/jzus.2006.A1690 · 0.61 Impact Factor
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ABSTRACT: The provision of real-time low-latency video appli-cations (e.g., interactive video tele-conferencing) over a wireless network is a significant research challenge. In this paper, we propose an encoder side error-resilient scheme (PGOP), by which we can stop the temporal error propagation in a progressive manner such that the constraint of encoder buffer delay can be satisfied. We compare the refreshing capability of our scheme to the well-known group of picture (GOP) scheme: with an equivalent refreshing capability, the PGOP scheme out-performs the GOP scheme in the low-latency scenario, showing better spatial and temporal quality for both frame-level and macroblock-level rate control modes. Furthermore, PGOP shows a significant decoding qual-ity gain over GOP in a simulated wideband code divi-sion multiple access mobile network.
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ABSTRACT: In order to enable a truly pervasive computing environment, next generation networks (including B3G and 4G) will merge the broadband wireless and wireline networking infrastructure. However, due to the tremendous complexity in administration and the unreliability of the wireless channel, provision of hard-guarantees for services on such networks will not happen in the foreseeable future. This consequently makes it particularly challenging to offer viable AV conferencing services due to their stringent synchronization, delay and data fidelity requirements. We propose in this paper a robust application-level solution for wireless mobile AV conferencing on B3G/4G networks. Expecting no special treatment from the network, we apply a novel adaptive delay and synchronization control mechanism to maintain the synchronization and reduce the latency as much as possible. We also employ a robust video coding technique that has better error-resilience capability. We investigate the performance of the proposed solution through simulations using a three-state hidden Markov chain as the generic end-to-end transport channel model. The results show that our scheme yields tight synchronization performance, relatively low end-to-end latency and satisfactory presentation quality. The scheme successfully provides a fairly robust AV conferencing service.Proceedings of SPIE - The International Society for Optical Engineering 12/2004; DOI:10.1117/12.587218 · 0.20 Impact Factor