spaper20 - Adjusting Forward Error Correction with Temporal...

Info iconThis preview shows pages 1–2. Sign up to view the full content.

View Full Document Right Arrow Icon
Adjusting Forward Error Correction with Temporal Scaling for TCP-Friendly Streaming MPEG HUAHUI WU, MARK CLAYPOOL, and ROBERT KINICKI Worcester Polytechnic Institute New TCP-friendly constraints require multimedia Fows to reduce their data rates under packet loss to that of a conformant TCP Fow. To reduce data rates while preserving real-time playout, temporal scaling can be used to discard the encoded multimedia frames that have the least impact on perceived video quality. To limit the impact of lost packets, ±orward Error Correction (±EC) can be used to repair frames damaged by packet loss. However, adding ±EC requires further reduction of multimedia data, making the decision of how much ±EC to use of critical importance. Current approaches use either inFexible ±EC patterns or adapt to packet loss on the network without regard to TCP-friendly data rate constraints. In this article, we analytically model the playable frame rate of a TCP-friendly MPEG stream with ±EC and temporal scaling, capturing the impact of distributing ±EC within MPEG frame types with interframe dependencies. ±or a given network condition and MPEG video encoding, we use our model to exhaustively search for the optimal combination of ±EC and temporal scaling that yields the highest playable frame rate within TCP-friendly constraints. Analytic experiments over a range of network and application conditions indicate that adjustable ±EC with temporal scaling can provide a signi²cant performance improvement over current approaches. Extensive simulation experiments based on Internet traces show that our model can be effective as part of a streaming protocol that chooses ±EC and temporal scaling patterns that meet dynamically-changing application and network conditions. Categories and Subject Descriptors: C.2.m [ Computer-Communication Networks ]: Miscellaneous General Terms: Performance, Design Additional Key Words and Phrases: Multimedia networking, MPEG, forward error correction, TCP-friendly 1. INTRODUCTION As the number of active Internet users continues to grow and streaming media applications become more commonplace, the number of Fows and the volume of data traversing the Internet is increasing quickly. The sheer number of possible users and applications at any point in time raises the probability of streaming multimedia Fows encountering congestion problems. To overcome short-term congestion and avoid long-term congestion collapse, the Internet relies upon the congestion control mechanisms in Transmission Control Protocol (TCP), the current dominant transport protocol on the Internet. While streaming Fows have traditionally selected UDP over TCP [Mena and Heidemann 2000; Wang et al. 2001], there is a growing consensus that all Internet applications must be TCP-friendly. A Fow is TCP-friendly if its data rate does not exceed the maximum data rate from a conformant TCP con- nection under equivalent network conditions. There are proposed approaches to detect and restrict the bandwidth of non-TCP-friendly Fows [Mahajan et al. 2001]. Thus, networking researchers have
Background image of page 1

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon
Image of page 2
This is the end of the preview. Sign up to access the rest of the document.

Page1 / 23

spaper20 - Adjusting Forward Error Correction with Temporal...

This preview shows document pages 1 - 2. Sign up to view the full document.

View Full Document Right Arrow Icon
Ask a homework question - tutors are online