Abstract


With the increasing deployment of Internet P2P/overlay streaming systems,
more and more clients use mobile devices,
such as smart phones, PDAs, to access these Internet streaming services.
Compared to wired desktops,
mobile devices normally have smaller screen size, less color depth,
and lower bandwidth and thus cannot correctly and effectively render
and display the data streamed to desktops.

To address this problem, in this study, we propose PAT
(Peer-Assisted Transcoding) to enable effective online transcoding
in P2P/overlay streaming. PAT has the following unique features.
First, it leverages active peer cooperation without demanding
infrastructure support, such as a transcoding server. Second, as
online transcoding is computationally intensive while the diverse
devices used by participating nodes may have limited computing power
and related resources (e.g., battery, bandwidth), an additional
overlay, called metadata overlay, is constructed to instantly share
the intermediate transcoding result of a transcoding procedure with
other transcoding nodes to minimize the total computing overhead in
the system. The experimental results collected within a realistic
simulated testbed show that by consuming 6% extra bandwidth, PAT
could save up to 56% CPU cycles for online transcoding.