Flexilink: A unified low latency network architecture for multichannel live audio (original) (raw)

Next-generation audio networking engineering for professional applications

2012

This paper presents an overview of the present and the future of audio networking and its needs, and focus on a light-weight generic architecture that we had experienced on multichannel spatial sound streamed to multiple recipients, in the context of 3D multimedia environment, and which should fit all the current and future requirements of professional audio applications.

Buffer management for streaming real time audio in IP networks

Real time audio transmission over the internet has become increasingly popular in many application areas, in particular in the commercial and entertainment sectors. However, the most challenging problem of end-to-end delay over an IP network needs to be addressed and is a topic of current ongoing research. In this paper various issues related to streaming real time audio in an IP network including the protocols used, problems faced in transmission and reception have been reviewed. A new scheme to evaluate the effect of buffer size during reception of an audio transmission in order to achieve an optimized playback is developed and tested. This method can be used to optimize the reception quality with respect to time and provide a way to reduce the noise effects at the receiver. It helps to stress out the factors affecting audio playback performance for the consumer.

A low-latency full-duplex audio over IP streamer

2006

LDAS (Low Delay Audio Streamer) is software for transmitting full duplex high-quality multi-channel audio with low end-to-end latency over IP networks. It has been designed and implemented as a tool for research into distributed multimedia interaction and quality of service in telecommunications. LDAS runs on Linux, using the ALSA sound drivers and libraries. It uses UDP as its transport protocol. A flow control scheme is used to keep the sender and receiver synchronised and to deal with transmission errors. Tests have shown end-to-end latencies (from analog input to analog output) down to around five milliseconds over a minimal network.

Latency in Audio Ethernet Networks

PREPRINTS-AUDIO ENGINEERING SOCIETY, 2003

In a time when several audio Ethernet networking solutions are being studied and developed, the analysis of the latency introduced by theses networks is fundamental. This analysis is the subject of the present paper, and is necessary not only to enable the identification of the factors that can be optimised, but also to support the decision about the possibility or not of the inclusion of in-band synchronism signalling.

Low-Latency Audio on Linux by Means of Real-Time Scheduling

In this paper, we propose to use resource reservations scheduling and feedback-based allocation techniques for the provisioning of proper timeliness guarantees to audio processing applications. This allows real-time audio tasks to meet the tight timing constraints characterizing them, even if other interactive activities are present in the system. The JACK sound infrastructure has been modified, leveraging the real-time scheduler present in the Adaptive Quality of Service Architecture (AQuoSA). The effectiveness of the proposed approach, which does not require any modifiction to existing JACK clients, is validated through extensive experiments under different load conditions.

Possibilities in network transport protocols to audio stream application context

Audio streams have always been seen as a kind of network application that don't care about the packet loss or data integrity. In the same way, it always appears as a latency-sensitive application. However, different scenarios may be mapped from different uses of these resource onto a network data distribution. Although many applications are using UDP protocol, there are some possibilities of transport protocol to the thiscenario. Thus, this paper will present four different transport protocol on the TCP/IP stack: TCP, UDP, STCP and DCCP. Theoretical comparison will present the protocol features and a minimal protocol transport socket implementation as a Pure Data external will be presented to send multi channel audio through network. This research stands implementation of Medusa-a distributed sound environment.

JackTrip: Under the Hood of an Engine for Network Audio

Journal of New Music Research, 2010

The design of a platform for bi-directional musical performance using modern WAN networks poses several challenges that are different from related applications, e.g., synchronous LAN studio systems or uni-directional WAN streaming. The need to minimize as much as possible audio latency and also maximize audio quality requires specific strategies which are informed, in part, by musical decisions.

A simplified approach to high quality music and sound over IP

COST-G6 Conference …, 2000

Present systems for streaming digital audio between devices connected by internet have been limited by a number of compromises. Because of restricted bandwidth and "best effort" delivery, signal compression of one form or another is typical. Buffering of audio data which is needed to safeguard against delivery uncertainties can cause signal delays of seconds. Audio is in general an unforgiving test of networking, e.g., one data packet arriving too late and we hear it. Trade-offs of signal quality have been necessary to avoid this basic fact and until now, have vied against serious musical uses.

Best Practices in Network Audio - AES WHITE PAPER

J. Audio Eng. Soc, 2009

Analog audio needs a separate physical circuit for each channel. Each microphone in a studio or on a stage, for example, must have its own circuit back to the mixer. Routing of the signals is inflexible. Digital audio is frequently wired in a similar way to analog. Although several channels can share a single physical circuit (e.g., up to 64 with AES10), thus reducing the number of cores needed in a cable. Routing of signals is still inflexible and any change to the equipment in a location is liable to require new cabling. Networks allow much more flexibility. Any piece of equipment plugged into the network is able to communicate with any other. However, installers of audio networks need to be aware of a number of issues that affect audio signals but are not important for data networks and are not addressed by current IT networking technologies such as IP. This white paper examines these issues and provides guidance to installers and users that can help them build successful networked systems.