This paper aims to inform, educate and stimulate interest in the possibilities and challenges in the area of audio-over-IP for multi-player interactive gaming. It draws on the expertise of many audio engineers in the fields of broadcast and telecom to bring together the reasons and rationale behind the problems and issues.
It also aims to bring to the table information that may well be the solution to some of the problems and prepare the industry for a full interactive audio experience across IP networks.
Viable distribution of Multi-channel
Audio-over-IP for Live and Interactive "Voice
Talent" based Gaming using High-quality,
Low-latency Audio Codec technology
a technical white paper
by APTX
www.aptx.com
ABSTRACT
The delivery of multi-channel audio - from mono to surround sound - in real-time over public IP networks
for the purpose of interactive crowd-participant gaming presents a significant design engineering challenge
to games developers, console manufacturers, ISPs and CDNs. Leveraging expertise gained in professional
broadcasting and recording studio post-production, APT has developed a robust and scalable audio codec
technology that meshes with popular gaming systems to realize low-latency distribution of high-quality
audio for immersive, instantaneous audio experiences in massively multi-player online games involving
interactive audience responses.
INTRODUCTION
This paper aims to inform, educate and stimulate interest in the possibilities and challenges in the area of
audio-over-IP for multi-player interactive gaming. It draws on the expertise of many audio engineers in the
fields of broadcast and telecom to bring together the reasons and rationale behind the problems and issues.
It also aims to bring to the table information that may well be the solution to some of the problems and
prepare the industry for a full interactive audio experience across IP networks. THE STATE OF AUDIO-OVER-IP FOR GAMING
Bringing an immersive, interactive audio experience to a vast number of discreet users geographically
dispersed across the world creates a unique set of challenges to be overcome. As technology has improved
and bandwidth has increased, so the quality of games and user expectation has increased. The present and
next generation of gamers see the potential of the IP networks that surround everyone to be used for
interactive experiences. Whilst demonstrations of these technologies can be seen and heard across smaller
networks, the challenges for larger networks remain.
The geographical distribution of the participants and audience places challenges in the path of interaction.
Whilst IP networks provide almost unlimited connectivity to the most inaccessible places on the planet, and
the most technically congested at bandwidths that can support higher and higher quality content, it remains
a challenge to use these networks for interactive transfer of audio. Systems such as CobraNet [1] and
EtherSound [2] distribute audio over local area networks very efficiently with minimal latency.
To try and summarise the problems: . Delay/Consistency: This comes from the characteristics of a packet network. The flexibility that
packet based networks bring also beings challenges for consistency of delivery. The staggered and
inconsistent arrival times, Jitter, of the packets, requires that end points buffer enough audio to
mask the longest arrival time.
. Delay/Throughput: Transferring a packet over a large geographic area, through congested regions
produces challenges for network providers. The ability to have a fair and reasonable approach to all
users, opposes the need in real-time systems for guaranteed bandwidth availability. . Delay/Audio compression: Today there are some great technologies for compression audio to bit rates that can be realistically transferred across even the most restrictive bandwidth circuits. The difficulty faced by these algorithms that the analysis of audio to reduce it to the bandwidths required often creates delays that prohibit its use in real time environments. . Delay/P... [download for more]
