When weighing codecs for any purpose, RF Specialties advises broadcasters to consider four important algorithm characteristics: bandwidth, delay, robustness, and cost. The type of application will greatly influence the trade-offs for each.
Live programming, for example, generally is not suited to algorithms with high delay. Low-delay algorithms such as apt-X and G.722, which is an international telephone standard probably used in more production houses than any other algorithm, are more suited to this application. However, G.722 is limited to 7.5kHz audio bandwidth, so it is not suitable for high-bandwidth applications.
Conversely, apt-X is capable of 20kHz stereo, depending on the data rate used, and is highly immune to transcoding artifacts. These characteristics make this algorithm an ideal candidate for high-quality audio production and STLs. This algorithm's drawback, unfortunately, is its high transmission overhead.
ISO/MPEG Layer 2, a popular algorithm with newly upgraded sample rates and an improved acoustical model, is an ideal candidate for full 15kHz over two low-cost 56kbps or 64kbps (SW56 or ISDN) lines. Its drawbacks: low immunity to transcoder artifacts and high delay.
These algorithms can be found in a number of products, including codec units by AEQ, CCS, Comrex, and RE America. Call RF Specialties before making a decision.
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