On combining temporal scaling and quality scaling for streaming MPEG

Temporal Scaling and Quality Scaling are both widely-used techniques to reduce the bitrate of streaming video. How-ever, combinations and comparisons of Temporal and Qual-ity Scaling have not been systematically studied. This re-search extends previous work to provide a model for combin-ing Temporal and Quality Scaling, and uses an optimization algorithm to provide a systematic analysis of their combina-tion over a range of network conditions and video content. Analytic experiments show: 1) Quality Scaling typically per-forms better than Temporal Scaling, with performance dif-ferences correlated with the motion characteristics of the video. In fact, when the network capacity is moderate and the loss rate is low, Quality Scaling performs nearly as well as the optimal combination of Quality and Temporal Scal-ing; 2) when the network capacity is low and the packet loss rate is high, Quality Scaling alone is ineffective, but a combination of Quality and Temporal Scaling can provide reasonable video quality; 3) adjusting the amount of For-ward Error Correction (FEC) provides significantly better performance than video streaming without FEC or video streaming with a fixed amount of FEC. 1

EFFICIENT WIRELESS VIDEO TRANSMISSION VIA LINKLAYER FEC FOR VIDEO COMMUNICATIONS

In this paper, new analysis and performance of robust error-model are presented for MPEG-4 video stream over wireless point-to-point network. Analytical expressions assume a noisy wireless environment causing frequent and random bit errors associated with packets. By this model, the temporal video scalability can be evaluated under TCP-Friendly Rate Control (TFRC) transmission when the Bose-Chaudhuri-Hochquenghem (BCH) channel coding is employed as a forward-error- correction (FEC) at a radio link layer. A FEC provides an efficient throughput access on wireless network. The numerical results clearly indicate that a quality of service (QoS) can be improved at low channel SNR region when the maximum channel coding throughput is achieved

A Framework of Video Bit-Stream Scalability and Efficient, Secure Social Video Sharing in the Clouds

No Abstrac

A testbed of erasure coding on video streaming system over lossy networks

As one of the most challenging aspects of streaming video over lossy networks, the technology for controlling packet losses has attracted more and more attention. Erasure coding is one of the ideal choices to deal with this problem. In most cases, the researchers need an effective method or tool to validate the erasure codes used for dealing with different packet loss patterns. Although some previous work has been done on employing erasure codes in video streaming system, few actual buildups and experiments which involve implementation of erasure codes against real packet loss in streaming systems have been reported. In this paper, we focus on constructing a testbed that integrates loss pattern generation and erasure coding implementation into video streaming services over lossy networks. With this approach, we are able to assess the capability of erasure coding in packet loss control and compare the performances of the video streaming systems with and without erasure coding. As an example, we have implemented the Reed-Solomon (7, 5) code for protecting MPEG streaming data under random packet losses. Experiment results show that the replay quality can be improved significantly by using erasure coding in video streaming systems, and that the testbed can suggest appropriate erasure code parameters for different loss environments

Проблемы передачи потокового видео по симплексному каналу сети с потерями данных

Разработана классификация основных проблем и задач, связанных с потерей части информации при передаче потокового видео по симплексному каналу связи, а также направлений в области их решения. Показано, что метод прямого исправления ошибок (ПИО) является наиболее общим подходом защиты от ошибок в рамках рассматриваемой задачи. Проанализированы работы в данной области и показана необходимость разработки нового метода применения ПИО, не привязанного к способу кодирования видеоизображения, с переменно-дискретным коэффициентом избыточности, обладающего низкой сложностью вычислений и обеспечивающего работу в режиме реального времени на современных компьютерах.Розроблено класифікацію основних проблем і задач, пов’язаних з утратою частини інформації при передачі потокового відео симплексним каналом зв’язку, а також напрямків в області їхнього рішення. Показано, що метод прямого виправлення помилок (ПВП) є найбільш загальним підходом захисту від помилок у рамках розглянутого завдання. Проаналізовано роботи в даній області та показано необхідність розробки нового методу застосування ПВП, що не прив’язаний до способу кодування відеозображення, зі змінно-дискретним коефіцієнтом надлишковості, що має низьку складність обчислень і забезпечує передачу даних у режимі реального часу на сучасних комп’ютерах.Classification of problems and tasks related to loss of a part of data in case of video streaming transmission over simplex channel and directions in domain of their solving are developed. It is shown that forward error correction (FEC) is the most general approach to error protection within the scope of the given task. A number of works in the given field are analyzed and necessity of new FEC method development is shown. The method should be independent of video coding scheme, with varying redundancy ratio for each data element and a speed of calculations sufficient for using in real time on modern computers

ChitChat: Making Video Chat Robust to Packet Loss

Video chat is increasingly popular among Internet users. Often, however, chatting sessions suffer from packet loss, which causes video outage and poor quality. Existing solutions however are unsatisfying. Retransmissions increase the delay and hence can interact negatively with the strict timing requirements of interactive video. FEC codes introduce extra overhead and hence reduce the bandwidth available for video data even in the absence of packet loss. This paper presents ChitChat, a new approach for reliable video chat that neither delays frames nor introduces bandwidth overhead. The key idea is to ensure that the information in each packet describes the whole frame. As a result, even when some packets are lost, the receiver can still use the received packets to decode a smooth version of the original frame. This reduces frame loss and the resulting video freezes and improves the perceived video quality. We have implemented ChitChat and evaluated it over multiple Internet paths. In comparison to Windows Live Messenger 2009, our method reduces the occurrences of video outage events by more than an order of magnitude