Mobile Radio Production Tools to be Topic at NAB
Broadcast Engineering Conference

Radio remotes are a content staple, providing variety and community interest to local radio programs. A session at the upcoming NAB Broadcast Engineering Conference (BEC, April 9 – 14, 2011, Las Vegas, Nev. – see below for additional information) titled “The Future of Radio Broadcasting” includes a paper, excerpted here, which presents an overview of several new small, mobile content production and delivery tools, including the video and audio capabilities of enhanced 3G/4G smartphones which provide for recording, editing, real-time streaming and uploading from the field. “Next Generation of Radio Content Collection and Delivery Tools” was authored by Pierre Robidoux, senior engineer, CBC/Radio-Canada.

INTRODUCTION – using a phone to go on air is nothing new. What is new, though, is going on air with a portable wireless device that sounds as good as a studio system. Newer still is having a small device – a smartphone – in the palm of your hand capable of doing mobile content production and contribution for radio. This paper doesn’t endorse or promote any particular smartphone brand or IP audio codec. It merely presents the various options available to broadcast radio stations seeking IP/Ethernet-based solutions for mobile wireless audio production and collection.

WHAT IS A SMARTPHONE? – the first known use of this word was in 1997. A smartphone is often described as a cell phone with some “computing capabilities.” It can be also defined as a very small mobile computer with wireless (data) communication capability, offering (cellular) digital telephony, text messaging, Web access and a host of other applications such as still picture photography and audio/video recording. Technically, a smartphone is just another IP “end device” accessing the IP-based studio production system from the outside.

As a reference for comparison, below are some specifications for the first portable computer, manufactured by the Osborne Computer Corporation (shown in photo at right, with an early model wireless phone):

WIRELESS AND INTERNET NETWORKS – on what network is the data (or signal) produced by a smartphone (or a small portable wireless audio codec) transported? The answer is twofold:

A real-time audio stream will normally use UDP over IP or RTP/UDP over IP for transport. Also, named carriers, operators or wireless service providers offer either the CDMA/EV-DO or the GSM/HSPA (voice/data) communication protocol. It should be noted that even if these protocols offer upload bit rates in the Mbps range, streaming 256 kbps or 384 kbps is often a challenge or simply impossible. Smartphones are generally locked (i.e., the device is tied to a specific carrier) and each provider supports only a limited number of smartphones. An unlocked smartphone may be used on any carrier’s network (if supported). The new 4G protocols, LTE (Long Term Evolution) and LTE-Advanced, will offer higher bit rates and the potential for some form of quality of service (guaranteed access and minimal bandwidth).

COMPRESSION ALGORITHMS – numerous choices have to be made regarding audio data rates, modes and even packet sizes (for some algorithms). The proper choice of compression algorithm and settings will depend on the:

When digital audio signals pass through multiple encode/decode cycles, this is generally referred to as cascading. Some coding schemes are more resilient than others to multiple cascades. Audio signal degradation will be more severe when several different coding algorithms are used on the same cascade.

Mr. Robidoux will present this paper on Sunday, April 10, 2011 starting at 9:30 a.m. in room S228 of the Las Vegas Convention Center. It will also be included in its entirety in the 2011 NAB Broadcast Engineering Conference Proceedings, on sale at the 2011 NAB Show Store and available on-line (after the Show) from the NAB Store. Other papers being presented during this session include the following:

For additional conference information visit the NAB Show website.