Mp3PRO is forward- and backward-compatible with MP3 and extends upper frequency response, Thomson said.
When recorded at a 64kbps datarate, for example, a standard MP3 file's frequency response goes up to about 8.7kHz. An mp3PRO file at 64kbps, in contrast, delivers response up to 16kHz, Thomson said.
As for compatibility, Mp3PRO decoders will be able to play back standard MP3 files with MP3 quality, Thomson said.
In addition, content encoded in mp3PRO can be played back in all traditional MP3 players with traditional MP3 sound quality, the company said. A 64kbps mp3PRO file, for example, would sound like a 64kbps MP3 file when played through an MP3 decoder.
Texas Instruments technologist Randy Cole, however, isn't so sure, but in any case, he said, "most people probably won't notice the difference." He explained it this way:
If a consumer creates a 64kbps mp3PRO file, "some of the 64kbps is used for mp3PRO information [high-frequency information] that only a PRO decoder knows how to handle, so a standard MP3 decoder has less than 64kbps to work with," Cole explained. However, the amount is "relatively small," he said.