Adaptive Streaming of Combined Audio/Video Content over Wireless Networks

Abstract

Abstract. This paper describes a method for robust streaming of combined MPEG-2 audio/video content over in-home wireless networks. We make use of currently used content distribution formats and network protocols. The transmitted bit-rate is constantly adapted to the available network bandwidth, such that audio and video artifacts caused by packet loss are avoided. Bit-rate adaptation is achieved by using a packet scheduling technique called I-Frame Delay (IFD), which performs priority-based frame dropping upon insufficient bandwidth. We show an implementation using RTP and an implementation using TCP. Measurements on a real-life demonstrator set-up demonstrate the effectiveness of our approach.

Adaptive Streaming of MPEG-based Audio/Video Content over Wireless Networks

“…The algorithm is characterized by the following: 1) buffer fullness is indicated by the number of frames currently in the buffer (not the number of bytes), 2) less important frames (B-frames) are dropped in favor of more important frames (I-and P-frames), 3) the transmission of I-frames is delayed when conditions are bad but as little as possible omitted, even if they are out-of-date w.r.t. the display time, because they can still be used to decode subsequent interpredicted frames 1 . The IFD mechanism is based on two parts: 1) during parsing and packetization of the stream into network packets, the stream is analyzed and the packets are tagged with a priority number reflecting the frame type (I/P/B) 2 scheduler when the bandwidth is insufficient.…”

“…This paper is an extension of earlier publication submitted to IFIP/IEEE International Conference on Management of Multimedia and Mobile Networks and Services [1]. Additional work included here covers extension of the demonstator server and presented algorithm to handle also the streams encoded with MPEG-4/H.264 codec (in Section III-E), results of experiments for streams with H.264 content previously done only for streams with MPEG-2 content (in Section IV) and evaluation of picture quality delivered by our algorithm (in Section IV-C).…”