Low-delay Video Transmission Research Articles

Low delay error resilience algorithm for H.265|HEVC video transmission

Transmission of high-resolution compressed video on unreliable transmission channels with time-varying characteristics such as wireless channels can adversely affect the decoded visual quality at the decoder side. This task becomes more challenging when the video codec computational complexity is an essential factor for low delay video transmission. High-efficiency video coding (H.265|HEVC) standard is the most recent video coding standard produced by ITU-T and ISO/IEC organisations. In this paper, a robust error resilience algorithm is proposed to reduce the impact of erroneous H.265|HEVC bitstream on the perceptual video quality at the decoder side. The proposed work takes into consideration the compatibility of the algorithm implementations with and without feedback channel update. The proposed work identifies and locates the frame’s most sensitive areas to errors and encodes them in intra mode. The intra-refresh map is generated at the encoder by utilising a grey projection method. The conducted experimental work includes testing the codec performance with the proposed work in error-free and error-prone conditions. The simulation results demonstrate that the proposed algorithm works effectively at high packet loss rates. These results come at the cost of a slight increase in the encoding bit rate overhead and computational processing time compared with the default HEVC HM16 reference software.

Ultrasound Video Streaming using HEVC-XLD in WiMAX Networks

Medical video communication system has been adopted widely in standard clinical practise to provide an adequate quality video diagnostic. In the existing m-health application, significant advance methods has been produced to emerge the high efficiency video compression methods with a promising wireless network for emergency situation in daily clinical practice. To transmit the medical ultrasound video effectively from user side to expert side, this proposed work utilize the upcoming standard technique High efficiency video coding (HEVC) for video compression. HEVC provides equal perceptual video quality by 50% bit-rate reduction range with high-resolution and low-delay video transmission. The cross layer framework over the WiMAX network is adapted to improve the throughput of the network considerably and the quality of service is optimized in the network environments. The experimental evaluations of the proposed scheme indicate that it produce a higher PSNR rate per frame and the best high resolution ultrasound video quality.

Optimization of Delay-Constrained Video Transmission for Ad Hoc Surveillance

Recent increases in demand by militaries and disaster relief operations has greatly accelerated research on delay-constrained video surveillance with low-delay and high-quality video transmission. The following factors should be systematically analyzed due to the tradeoff between low delay and high quality: the visual importance of surveillance objects, quality degradation due to wireless channel dynamics, and variant end-to-end delay. We propose and optimize a low-delay video transmission technique for video surveillance over an ad hoc network. The proposed protocol is composed of intercommunication and intraprocessing parts. Through intercommunication optimization, we identify an optimal routing path and an associated relaying in terms of channel throughput that meet the source-rate, the flow-rate, and delay constraints. Through intraprocessing optimization, we identify an optimal packet length and an associated number of packets to adapt to the delay in the variant dynamic channel. Through simulations, we demonstrate that delay and throughput control significantly contribute to improvements in visual quality of up to 1.7-3 dB compared with conventional schemes.

Accurate Bitrate Model and Greedy-Based Rate Controller for Low Delay Video Transmission

We develop a q -domain characteristic-based rate model for video transmission. Specifically, we extract three characteristics from the quantized discrete cosine transform spectra to construct an accurate rate-quantization (R-Q) model. Moreover, the extraction of the proposed characteristics requires only simple additive operations (additions, subtractions, and comparisons) and few multiplications. Based on the q-domain characteristic-based bitrate model, we develop an efficient two-level greedy-based rate controller for low delay video transmission. Extensive experimental results show that due to the efficiency and accurate estimation of both macroblock and frame-level R-Q models, the proposed rate controller better maintains the source bitrate to meet a predefined buffer delay time, and substantially enhances visual quality as compared with other rate controllers.

A $q$-Domain Characteristic-Based Bit-Rate Model for Video Transmission

For low-delay video transmission, we introduce a q -domain characteristic-based bit-rate model. Specifically, three characteristics are efficiently extracted from the quantized DCT spectra to construct the bit-rate model. Extensive experimental results show that our rate model can provide more accuracy with lower complexity than existing models.