A video retrieval protocol with video data prefetch and packet retransmission considering play-out deadline

Abstract

Most of current video retrieval systems use video transfer protocols such that servers simply transmit video packets in the same rate as clients play them. If any packets are corrupted during transmission, they will be lost and cannot be recovered by retransmission. In video retrieval systems, howevel; the video data are stored in servers and clients can prefetch them prior to playing. So, it might be possible for the video retrieval systems to make corrupted video packets retransmitted before play-out dead line. But the application of existing reliable protocols causes problems such that, i f a packet does not arrives before the dead line due to retransmission, the packets following it will not be delivered to the upper layer even if they have already arrived.In this papel; we proposed a new video transfer protocol for video retrieval systems over ATM network, which provides the video data prefetch, the jlow control for video buffel; the selective retransmission with skipping function for video packets late for the play-out dead line, and the resynchronaization function for video buffeel: We have implemented an experimental system using our protocol and evaluated the pelformanee. The results of performance evaluation shows that the proposed protocol decreases the number of unplayed video data to less than 1/70 compared with the conventional non-retransmission protocol when random bit errors with BER of I O p 6 are inserted in an ATM network. I~t r~d u c t i~~Recently, there are many studies on video retrieval systems, such as Video-on-Demand systems, in which clients retrieve video data stored in servers through networks. Most of these systems use a video transfer protocol such that servers simply transmit video packets in the rate corresponding to the playing rate in clients[ 1] [2]. If any packets are corrupted during the transmission, they will be lost and cannot be recovered by retransmission. The main reasons for adopting such a non-reliable protocol are as follows. First, video packets must be delivered before the play-out dead line expires, and it is considered that the retransmission will not satisfy this requirement. Secondly, it is considered that, in order to realize high speed video transfer, a simple protocol will be appropriate for reducing the processing overhead of protocols.In video retrieval systems, however, video data are stored in servers and it is possible that clients prefetch them prior to playing. This feature is different from video conference systems in which video data are generated in a real time manner. So, for video retrieval systems, it is possible to arrange time enough for the retransmission before the playout. Moreover, resulting from the progress of hardware and software technologies, some software for reliable protocols with packet retransmission attains high throughput over 100 Mbps [3]. Therefore, it is considered that video retrieval systems can recover corrupted packets by retransmission, using buffer introduced for prefetching video data. So far, there are some research ...

Cross-Layer Packet Retry Limit Adaptation for Video Transport Over Wireless LANs

“…Simply setting the retry limit of a packet according to the packet's importance without taking into account the time cost cannot achieve the optimal performance. For performance evaluation, the fixed retry-limit scheme with two different retry limits, the EDF scheme [6], the L-PQ scheme proposed in [18], and the TAR scheme proposed in [22] and [23] were also implemented and compared with the proposed method. The above schemes represent three state-of-the-art strategies of retry limit adaptation in terms of presentation deadlines of packets, packet loss rate of video layers, and frame/packet-level influence, respectively.…”

“…There have been a few research works addressing the scheduling problem of retransmitted packets. For example, a simple scheduling-oriented retransmission method which takes into account the play-out deadline based on the early-deadline-first (EDF) principle was presented in [6] and [7]. The EDF method gives priority to the lost packets with earliest play-out deadlines in transmission, which may lead to the overriding of regular packets by the retransmitted packets.…”

Prioritized retransmission for error protection of video streaming over WLANs

“…5 and 6 show PSNR performance comparisons for the two test sequences. We compare the proposed scheme with the typical Early-Deadline-First (EDF) scheme [1] and that without retransmission protection. Since the proposed scheme choose to retransmit lost packets with higher impact values by dropping regular packets of less importance, it usually can achieve better trade-offs in terms of video quality.…”

“…Packet loss may lead to serious video quality degradation or even make the video clip un-decodable. Error protection for video streaming over WLAN has been an active research topic [1][2][3][4][5]. Automatic Retransmission reQuest (ARQ) is one of the most commonly used channel coding schemes for error protection, which is particularly useful to combat against burst errors.…”

“…Automatic Retransmission reQuest (ARQ) is one of the most commonly used channel coding schemes for error protection, which is particularly useful to combat against burst errors. For example, a typical schedulingoriented retransmission method was presented in [1] which takes into account the play-out deadline based on the Early-DeadlineFirst (EDF) principle. The EDF method chooses to retransmit the lost packets with earliest play-out deadlines, which may lead to the overriding of regular packets by the retransmitted packets.…”