When the spot block ends, the Orban card is signaled to resume using the program source coming from digital input 1 and thereafter it feeds the common program (heard by over-the-air users as well as stream-only users) to the inputs of all the encoders.

Our traffic department schedules the spot blocks for streaming media, just as it does for the spot blocks that run over the air on the associated radio station.

Some of the over-the-stream spots have visual elements associated with them. Metadata from the stream-only spots is forwarded (via our WAN) to our corporate streaming headquarters in Cincinnati, signaling servers there to add the visual elements by way of the Flash player used by the desktop-only streaming clients. Mass redistribution of the streams is handled by Akamai's CDN.

A hybrid approach

Figure 2. Sell and traffic stream-only ads using Ando Media’s ad insertion software in conjunction with the system (in this case, Enco). (Click image to enlarge.)

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I spoke with my friend Bryan Hubert, the chief engineer of Crista Ministry's radio stations in Washington state about its hybrid approach to streaming audio ad-insertion.

Crista wanted to sell and traffic all the stream-only ads itself, and it recognized the capabilities of Ando Media's ad-insertion software, so the group decided to use Ando in conjunction with its Enco system.

The system consists of two logs running in Enco, each with an associated audio output. A Broadcast Tools audio switcher is used to switch between sources, and that output is routed to the CPU where the Ando software resides (see Figure 2). This same CPU has an output that gets routed to a PPM encoder and then back. A streaming encoder then takes that PPM encoded source and sends it off to the Streamguys CDN for distribution to the end users.

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