A Reliable Scheme for Synchronizing Multimedia Data Streams under Multicasting Environment

Abstract

An emerging requirement in multimedia applications over the Internet is the provisioning of synchronized play out of multimedia streams on all the ultimate receivers. Most multimedia applications use real-time transport protocol/real-time control protocol (RTP/RTCP) to transport multimedia data over the internet. Internet Protocol (IP) network incurs a loss and/or delay of media packets resulting in distortions at receivers that can be perceived by the user. These distortions need to be removed before data is presented to the end user. To handle such issues inter-stream and intra-stream synchronization algorithms were developed by the researcher using RTP/RTCP protocols. These schemes could not work under multicasting environment properly. In this paper, we have presented an algorithm based on RTP/RTCP protocol that achieved synchronized playout of multimedia data under multicasting environment. The proposed scheme offers a modification in RTCP and usage of the Network Time Protocol (NTP) as a source of the common clock to achieve synchronized playout of multimedia data on multiple devices at the same time. We have implemented and tested our algorithm in Ericson Research Corporate Unit, Lulea, Sweden. Implementation results show that the proposed algorithm delivered accurately synchronized playout of multimedia data under all the possible scenarios defined in the experimental setup.

Keywords

• synchronization
• multimedia
• multicasting
• time stamping
• playout
• streaming