Browsing by Author "Dawood, Muneeb"

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    Error resilient packet switched H.264 video telephony over third generation networks.
    (De Montfort University, 2010) Dawood, Muneeb
    Real-time video communication over wireless networks is a challenging problem because wireless channels suffer from fading, additive noise and interference, which translate into packet loss and delay. Since modern video encoders deliver video packets with decoding dependencies, packet loss and delay can significantly degrade the video quality at the receiver. Many error resilience mechanisms have been proposed to combat packet loss in wireless networks, but only a few were specifically designed for packet switched video telephony over Third Generation (3G) networks. The first part of the thesis presents an error resilience technique for packet switched video telephony that combines application layer Forward Error Correction (FEC) with rateless codes, Reference Picture Selection (RPS) and cross layer optimization. Rateless codes have lower encoding and decoding computational complexity compared to traditional error correcting codes. One can use them on complexity constrained hand-held devices. Also, their redundancy does not need to be fixed in advance and any number of encoded symbols can be generated on the fly. Reference picture selection is used to limit the effect of spatio-temporal error propagation. Limiting the effect of spatio-temporal error propagation results in better video quality. Cross layer optimization is used to minimize the data loss at the application layer when data is lost at the data link layer. Experimental results on a High Speed Packet Access (HSPA) network simulator for H.264 compressed standard video sequences show that the proposed technique achieves significant Peak Signal to Noise Ratio (PSNR) and Percentage Degraded Video Duration (PDVD) improvements over a state of the art error resilience technique known as Interactive Error Control (IEC), which is a combination of Error Tracking and feedback based Reference Picture Selection. The improvement is obtained at a cost of higher end-to-end delay. The proposed technique is improved by making the FEC (Rateless code) redundancy channel adaptive. Automatic Repeat Request (ARQ) is used to adjust the redundancy of the Rateless codes according to the channel conditions. Experimental results show that the channel adaptive scheme achieves significant PSNR and PDVD improvements over the static scheme for a simulated Long Term Evolution (LTE) network. In the third part of the thesis, the performance of the previous two schemes is improved by making the transmitter predict when rateless decoding will fail. In this case, reference picture selection is invoked early and transmission of encoded symbols for that source block is aborted. Simulations for an LTE network show that this results in video quality improvement and bandwidth savings. In the last part of the thesis, the performance of the adaptive technique is improved by exploiting the history of the wireless channel. In a Rayleigh fading wireless channel, the RLC-PDU losses are correlated under certain conditions. This correlation is exploited to adjust the redundancy of the Rateless code and results in higher Rateless code decoding success rate and higher video quality. Simulations for an LTE network show that the improvement was significant when the packet loss rate in the two wireless links was 10%. To facilitate the implementation of the proposed error resilience techniques in practical scenarios, RTP/UDP/IP level packetization schemes are also proposed for each error resilience technique. Compared to existing work, the proposed error resilience techniques provide better video quality. Also, more emphasis is given to implementation issues in 3G networks.
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    Error resilient packet-switched video telephony with adaptive rateless coding and reference picture selection.
    (EUROSIS, 2010-12) Dawood, Muneeb; Hamzaoui, Raouf; Ahmad, Shakeel; Al-Akaidi, Marwan, 1959-
    Providing high-quality video for packet-switched wireless video telephony on hand-held devices is a challenging task due to packet loss, limited available bandwidth, and complexity constraints. We propose a low-complexity channel-adaptive error resilience technique that combines application-layer forward error correction (FEC) with rateless codes, retransmission, and reference picture selection. Experimental results for H.264 video sequences show that the proposed technique achieves significant peak-signal-to-noise ratio (PSNR) and percentage degraded video duration (PDVD) improvements over previous techniques in networks involving two wireless links.
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    Error-resilient packet switched H.264 mobile video telephony with LT coding and reference picture selection.
    (EURASIP, 2009-08) Dawood, Muneeb; Hamzaoui, Raouf; Ahmad, Shakeel; Al-Akaidi, Marwan, 1959-
    Packet switched video telephony over wireless networks for hand-held devices requires low-delay, low-complexity error control mechanisms to deal with packet loss. We present an efficient solution for 3G networks based on LT coding, reference picture selection, and cross-layer optimization. Experimental results on a 3G network simulator for H.264 compressed standard video sequences show that our method achieves significant peak-signal-to-noise ratio and percentage degraded video duration improvements over a state of the art technique.
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    Error-resilient packet-switched mobile video telephony with channel-adaptive rateless coding and early reference picture selection
    (Springer, 2016-02) Dawood, Muneeb; Hamzaoui, Raouf; Ahmad, Shakeel; Al-Akaidi, Marwan, 1959-
    Providing high-quality video for packet-switched wireless video telephony on handheld devices is a challenging task due to packet loss, varying bandwidth, and end-to-end delay constraints. While many error resilience techniques have been proposed for video transmission over wireless channels, only a few were specifically designed for mobile video telephony. We propose a low-complexity channel-adaptive error resilience technique for packet-switched mobile video telephony, which combines rateless coding, feedback, and reference picture selection. In contrast to previous approaches, our technique uses cumulative feedback at every transmission opportunity and predicts when decoding is likely to fail so that reference picture selection can be triggered at an early stage. Experimental results for H.264 video sequences show that the proposed technique can achieve improvements of 1.64 dB in peak signal-to-noise ratio over benchmark techniques in simulated Long-Term Evolution networks.
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    Level-based peer-to-peer live streaming with rateless codes
    (IEEE, 2012) Buyukkaya, Eliya; Ahmad, Shakeel; Dawood, Muneeb; Liu, Jiayi; Zhou, F.; Hamzaoui, Raouf; Simon, G.
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    Peer-to-Peer Live Video Streaming with Rateless Codes for Massively Multiplayer Online Games
    (Springer US, 2016-08-19) Ahmad, Shakeel; Bouras, Christos; Buyukkaya, Eliya; Dawood, Muneeb; Hamzaoui, Raouf; Kapoulas, Vaggelis; Papazois, Andreas; Simon, Gwendal
    We present a multi-level multi-overlay hybrid peer-to-peer live video system that enables players of Massively Multiplayer Online Games to simultaneously stream the video of their game and watch the game videos of other players. Each live video bitstream is encoded with rateless codes and multiple trees are used to transmit the encoded symbols. Trees are constructed dynamically with the aim to minimize the transmission rate at the source while maximizing the number of served peers and guaranteeing on-time delivery and reliability. ns-2 simulations and real measurements on the Internet show competitive performance in terms of start-up delay, playback lag, rejection rate, used bandwidth, continuity index, and video quality.
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    The social side of theory: A community-based narrative of research and theory.
    (Informing Science Institute, 2008) Stahl, Bernd Carsten, 1968-; Al-Amri, Jehad; Almullah, Suad; Dawood, Muneeb; Fidler, Christine; Halaweh, Mohanad; Ibekwe, Osita; Kanaan, Raed Kareem; Phythian, Michael James; Al-Shery, Abdullah; Swesi, Khaled; Tangai, Sarai