WorldCast and Orban have recently issued a press release about the APTmpX codec. We do not usually respond to something like this, and let our technology speak for itself. However, their press release contains some falsehoods about the current MPX composite codec landscape, that we cannot ignore. Their claims misrepresent the capabilities and performance of our codec. As a company committed to innovation and excellence, we feel it's necessary to set the record straight and address these inaccuracies.
We will start by responding to their claims, and end with briefly comparing real-world compression results.
Their claims
The key benefits over other MPX compression methods in the market is the absolute transparent nature of the codec, being rooted in ADPCM as opposed to a psychoacoustic code base. This gives the immediate benefit of maintaining perfect sonic fidelity and precise peak control of the high-end processor from which the MPX signal has been derived. The other crucial advantage with APTmpX, thanks to the transparent nature of the algorithm, is that it will not degrade in any way the Nielsen watermarking technology - used in the USA market to validate station ratings.
We agree that ADPCM can be superior for transparency, sonic fidelity, peak control and not degrading watermarking. Which is exactly why MicroMPX has always been ADPCM based. It's a benefit of both codecs, even though we see massive differences in fidelity between the two.
The APTmpX codec is the only reduced bandwidth codec technology for distributing analog FM composite today that doesn’t negatively impact watermark encoding.
This is simply not true, as MicroMPX has been showing for years now.
[APTmpX] audio quality is spectacular and it’s virtually indistinguishable from the source.
Let’s look at some comparisons of source and compressed audio to get an idea of how one would distinguish the two.
Head to head comparison
Our initial comparisons are based on the example files that are provided by WorldCast. Those samples do not seem to contain any audio that's difficult to handle for ADPCM-based codecs, unfortunately. More in-depth comparisons will have to follow after we return from the NAB Show in Las Vegas (come visit our booth, W3322!).
Despite the simple nature of the source material, there are very clear differences. Listening to the decoded version of their recording of Tom's Diner by Suzanne Vega, we can very clearly hear a metallic sound, most audible at 300 kbit.
To test what MicroMPX would do, we ran the provided source file through Stereo Tool, adding a pilot and RDS and performing MicroMPX encoding. We then decoded it with a MicroMPX decoder and demodulated the MPX signal, giving us our own decoded recording for direct comparison. There was no metallic effect at all.