Optimal packetisation of MPEG-4 using RTP over mobile networks

The introduction of third-generation wireless networks should result in real-time mobile video communications becoming a reality. Delivery of such video is likely to be facilitated by the realtime transport protocol (RTP). Careful packetisation of the video data is necessary to ensure the optimal trade-off between channel utilisation and error robustness. Theoretical analyses for two basic schemes of MPEG-4 data encapsulation within RTP packets are presented. Simulations over a GPRS (general packet radio service) network are used to validate the analysis of the most efficient scheme. Finally, a motion adaptive system for deriving MPEG-4 video packet sizes is presented. Further simulations demonstrate the benefits of the adaptive system

Layered Video Transmission on Adaptive OFDM Wireless Systems

Future wireless video transmission systems will consider orthogonal frequency division multiplexing (OFDM) as the basic modulation technique due to its robustness and low complexity implementation in the presence of frequency-selective channels. Recently, adaptive bit loading techniques have been applied to OFDM showing good performance gains in cable transmission systems. In this paper a multilayer bit loading technique, based on the so called "ordered subcarrier selection algorithm," is proposed and applied to a Hiperlan2-like wireless system at 5 GHz for efficient layered multimedia transmission. Different schemes realizing unequal error protection both at coding and modulation levels are compared. The strong impact of this technique in terms of video quality is evaluated for MPEG-4 video transmission

A Review of Error Resilience Techniques in Video Streaming

Abstract-Delivering video data of satisfactory quality over unreliable networks -such as the internet or wireless networks -is a demanding area which has received significant attention of the research community over the past few years. Given the fact that packet loss is inevitable and therefore the presence of errors granted, the effort is directed towards limiting the effect of these errors. A number of techniques have been developed to address this issue. This paper aims to summarize the most significant approaches for: error resilience, error concealment and joint encoder-decoder error control techniques, and to provide a thorough discussion of the benefits and drawbacks of these error control methods. Furthermore, two case studies of error resilience utilization are presented, namely Ad-hoc networks and Multimedia Broadcast Multiple Services (MBMS)

Adaptive intra refresh for robust wireless multi-view video

This thesis was submitted for the award of PhD and was awarded by Brunel University LondonMobile wireless communication technology is a fast developing field and every day new mobile communication techniques and means are becoming available. In this thesis multi-view video (MVV) is also refers to as 3D video. Thus, the 3D video signals through wireless communication are shaping telecommunication industry and academia. However, wireless channels are prone to high level of bit and burst errors that largely deteriorate the quality of service (QoS). Noise along the wireless transmission path can introduce distortion or make a compressed bitstream lose vital information. The error caused by noise progressively spread to subsequent frames and among multiple views due to prediction. This error may compel the receiver to pause momentarily and wait for the subsequent INTRA picture to continue decoding. The pausing of video stream affects the user's Quality of Experience (QoE). Thus, an error resilience strategy is needed to protect the compressed bitstream against transmission errors. This thesis focuses on error resilience Adaptive Intra Refresh (AIR) technique. The AIR method is developed to make the compressed 3D video more robust to channel errors. The process involves periodic injection of Intra-coded macroblocks in a cyclic pattern using H.264/AVC standard. The algorithm takes into account individual features in each macroblock and the feedback information sent by the decoder about the channel condition in order to generate an MVV-AIR map. MVV-AIR map generation regulates the order of packets arrival and identifies the motion activities in each macroblock. Based on the level of motion activity contained in each macroblock, the MVV-AIR map classifies frames as high or low motion macroblocks. A proxy MVV-AIR transcoder is used to validate the efficiency of the generated MVV-AIR map. The MVV-AIR transcoding algorithm uses spatial and views downscaling scheme to convert from MVV to single view. Various experimental results indicate that the proposed error resilient MVV-AIR transcoder technique effectively improves the quality of reconstructed 3D video in wireless networks. A comparison of MVV-AIR transcoder algorithm with some traditional error resilience techniques demonstrates that MVV-AIR algorithm performs better in an error prone channel. Results of simulation revealed significant improvements in both objective and subjective qualities. No additional computational complexity emanates from the scheme while the QoS and QoE requirements are still fully met.Tertiary Institution Trust Fund (TETFund) of Nigeri

Error-resilient coding tools in MPEG-4.

by Cheng Shu Ling.Thesis submitted in: July 1997.Thesis (M.Phil.)--Chinese University of Hong Kong, 1998.Includes bibliographical references (leaves 70-71).Abstract also in Chinese.Chapter Chapter 1 --- Introduction --- p.1Chapter 1.1 --- Image Coding Standard: JPEG --- p.1Chapter 1.2 --- Video Coding Standard: MPEG --- p.6Chapter 1.2.1 --- MPEG history --- p.6Chapter 1.2.2 --- MPEG video compression algorithm overview --- p.8Chapter 1.2.3 --- More MPEG features --- p.10Chapter 1.3 --- Summary --- p.17Chapter Chapter 2 --- Error Resiliency --- p.18Chapter 2.1 --- Introduction --- p.18Chapter 2.2 --- Traditional approaches --- p.19Chapter 2.2.1 --- Channel coding --- p.19Chapter 2.2.2 --- ARQ --- p.20Chapter 2.2.3 --- Multi-layer coding --- p.20Chapter 2.2.4 --- Error Concealment --- p.20Chapter 2.3 --- MPEG-4 work on error resilience --- p.21Chapter 2.3.1 --- Resynchronization --- p.21Chapter 2.3.2 --- Data Recovery --- p.25Chapter 2.3.3 --- Error Concealment --- p.28Chapter 2.4 --- Summary --- p.29Chapter Chapter 3 --- Fixed length codes --- p.30Chapter 3.1 --- Introduction --- p.30Chapter 3.2 --- Tunstall code --- p.31Chapter 3.3 --- Lempel-Ziv code --- p.34Chapter 3.3.1 --- LZ-77 --- p.35Chapter 3.3.2 --- LZ-78 --- p.36Chapter 3.4 --- Simulation --- p.38Chapter 3.4.1 --- Experiment Setup --- p.38Chapter 3.4.2 --- Results --- p.39Chapter 3.4.3 --- Concluding Remarks --- p.42Chapter Chapter 4 --- Self-Synchronizable codes --- p.44Chapter 4.1 --- Introduction --- p.44Chapter 4.2 --- Scholtz synchronizable code --- p.45Chapter 4.2.1 --- Definition --- p.45Chapter 4.2.2 --- Construction procedure --- p.45Chapter 4.2.3 --- Synchronizer --- p.48Chapter 4.2.4 --- Effects of errors --- p.51Chapter 4.3 --- Simulation --- p.52Chapter 4.3.1 --- Experiment Setup --- p.52Chapter 4.3.2 --- Results --- p.56Chapter 4.4 --- Concluding Remarks --- p.68Chapter Chapter 5 --- Conclusions --- p.69References --- p.7

Irregular Variable Length Coding

In this thesis, we introduce Irregular Variable Length Coding (IrVLC) and investigate its applications, characteristics and performance in the context of digital multimedia broadcast telecommunications. During IrVLC encoding, the multimedia signal is represented using a sequence of concatenated binary codewords. These are selected from a codebook, comprising a number of codewords, which, in turn, comprise various numbers of bits. However, during IrVLC encoding, the multimedia signal is decomposed into particular fractions, each of which is represented using a different codebook. This is in contrast to regular Variable Length Coding (VLC), in which the entire multimedia signal is encoded using the same codebook. The application of IrVLCs to joint source and channel coding is investigated in the context of a video transmission scheme. Our novel video codec represents the video signal using tessellations of Variable-Dimension Vector Quantisation (VDVQ) tiles. These are selected from a codebook, comprising a number of tiles having various dimensions. The selected tessellation of VDVQ tiles is signalled using a corresponding sequence of concatenated codewords from a Variable Length Error Correction (VLEC) codebook. This VLEC codebook represents a specific joint source and channel coding case of VLCs, which facilitates both compression and error correction. However, during video encoding, only particular combinations of the VDVQ tiles will perfectly tessellate, owing to their various dimensions. As a result, only particular sub-sets of the VDVQ codebook and, hence, of the VLEC codebook may be employed to convey particular fractions of the video signal. Therefore, our novel video codec can be said to employ IrVLCs. The employment of IrVLCs to facilitate Unequal Error Protection (UEP) is also demonstrated. This may be applied when various fractions of the source signal have different error sensitivities, as is typical in audio, speech, image and video signals, for example. Here, different VLEC codebooks having appropriately selected error correction capabilities may be employed to encode the particular fractions of the source signal. This approach may be expected to yield a higher reconstruction quality than equal protection in cases where the various fractions of the source signal have different error sensitivities. Finally, this thesis investigates the application of IrVLCs to near-capacity operation using EXtrinsic Information Transfer (EXIT) chart analysis. Here, a number of component VLEC codebooks having different inverted EXIT functions are employed to encode particular fractions of the source symbol frame. We show that the composite inverted IrVLC EXIT function may be obtained as a weighted average of the inverted component VLC EXIT functions. Additionally, EXIT chart matching is employed to shape the inverted IrVLC EXIT function to match the EXIT function of a serially concatenated inner channel code, creating a narrow but still open EXIT chart tunnel. In this way, iterative decoding convergence to an infinitesimally low probability of error is facilitated at near-capacity channel SNRs