The Web Browser as an Audio Codec: Source-Nexus Gateway

This article is part of the Source-Nexus Gateway User Guide

The arrival of web audio in the browser has sparked development in affordable, high-quality options for audio professionals to record and monitor remotely.

Source-Nexus Gateway is a new service from Source Elements built on cutting-edge features including a new high-quality codec called OPUS.

Deciding on using a new codec is not only about whether it provides suitable audio quality but also whether it offers the features you need, and about understanding how it works so you can make good technical decisions when setting up or if things go wrong.

What features makes it good for professional audio?

• High-quality audio streaming
• Low latency for interviews and radio conversations
• Easy setup
• Built-in recorder
• Easy conferencing
• Works everywhere - a great backup option that everyone should have

What features makes it not so good for professional audio?

• Accurate gain handling is not guaranteed
• Accurate clocking is not guaranteed
• May time-stretch, making file replacement and transport locking difficult
• Does not allow for predictable network setups
• No way to mitigate the hazards and effects of high-latency connections
• Cannot specify ports, thus hard to apply "QoS" tags

Comparing platforms

Leaving aside a discussion of hardware, we will compare the differences between building "downloadable" software, and developing on top of an existing platform such as a web browser. Ultimately, developers of downloadable software have complete control over an application that is written and designed from the ground up, whereas services that are reliant on web browsers have limitations.

As low-level developers we can highly tune our software for audio performance. This allows us to design features that integrate directly with sound applications, such as Pro Tools and Adobe Audition. We make accurate sound our priority. This includes the ability to automatically fix glitches caused by bandwidth problems (even after the recording is complete), and adding special features such as syncing timelines so you can remotely work with picture or for overdubbing.

Compare that to a web browser which is first and foremost a generic tool written to be run by millions of people to browse the entire Internet. Web browsers are used for email, Facebook, Internet Banking, watching Netflix and many more tasks. The new media features supported in Chrome (and soon in Firefox and iOS) are simply one of many exciting capabilities. So we keep in mind that while web browsers are not primarily designed for professional audio use we have engineered a product with the available media features to be as useful as possible in a professional audio context.

Benefits of using the Web Browser as an Audio Codec

There is strong demand for an accessible, affordable means of streaming high quality audio. New capabilities added to Google Chrome allow us to start building professional and sophisticated services. The web browser is a very familiar platform for many users: it is everywhere and already installed in many cases. As web developers we can innovate quickly and release amazing features that don't require dongles or serial numbers. It 'just works' and for many users is suitable for their needs.

Source-Nexus Gateway is Source Elements' browser-based codec that takes full advantage of the benefits of building on the browser. The Source-Nexus Gateway is easily extendable to allow future features such as video conferencing. It currently allows advanced features such as audio conferencing, built-in recording, Talkback, and better-than-ISDN bit-rates for excellent sound quality. But perhaps the most exciting feature is that because everyone has access to a web browser you can quickly connect to anyone in the world. All of this allows us to take advantage of the ubiquity of the browser to offer free services, including broadcast-quality streaming at 128kbps.

Challenges when using a Web Browser as an Audio Codec

Favors intelligibility over accuracy

While it may be accessible and at low cost, using a web browser for audio is essentially like using Skype: it favors intelligibility over accuracy. It will timestretch and lower the audio quality when bandwidth issue arise. Because the time factor is not consistent there is no reliable way to accurately sync to picture, overdub, or build features such as Source-Connect's Auto Restore and Replace. Most importantly, there is no guarantee that the remotely recorded file will fit in the exact same time space as the file recorded locally. 

So, a browser based codec is best for a "what you hear is what you get" workflow, and it's great for monitoring. It's not perfect for recording if you want to do detailed edits based on the stream and later "replace" the streamed recording with the original files: the editor might have issues if time stretching occurs. In extreme cases the time stretching can actually affect the way a performance is perceived by the producer; it can affect the performance by exaggerating the length of pauses or the speed at which you read copy.

No direct access to Audio Hardware settings

Further, because Chrome is managing the audio devices, we can't guarantee the exact handling of your audio hardware. You may experience sample-rate conflicts or level differences in the volume as the audio gets delivered. For example, Chrome may lower the level of audio to preemptively prevent any clipping.

Limited ability to work on strict networks

Connections using this browser-based method may fail if the network doesn't allow standard traffic; there are no ports or settings that the IT department can configure if problems arise. This is because this type of connection was developed to work in "almost all cases". So if your client's IT department or network has strict traffic rules there may be few to no options to get it to work, whereas dedicated software such as Source-Connect conforms to industry IT standards with available settings such as port forwarding, port binding, dedicated IP permissions and VPN networks.

No access to computer systems outside of browser

We must also consider the sandboxed nature of a web browser: developers access is limited for security purposes. For example, they have little to no access to the local file structure or direct control over the audio hardware attached to the computer.

No control over exact features

Browser developers, e.g.. Google or Mozilla, may disable features without warning. They may also not choose to implement key features at all: for example Apple and Microsoft are yet to build these new media technologies into Safari and Internet Explorer, let alone iOS. So as developers this leaves us unable to affordably provide services on all platforms.

Summary

Knowing these limitations will help you know what codec to use given the situation. The web browser codec is an excellent choice for wild reads, basic recording, radio and podcast interviews, monitoring, review and approval, and anything else that is not dependent on accurate time - "what you hear is what you get".

The future of web audio at Source Elements

Source Elements has been developing software and services for audio over the internet since 2003, beginning with Source-Connect that was released to the public in 2005. Since then, we have been in constant development: every year a new major upgrade has been released to take advantage of new operating system and DAW capabilities. We are already extending browser-based systems with software such as Source-Nexus I/O for recording and better integration in Pro Tools and which will soon be able to work with VST and AudioUnits hosts.