Thomson announced on Thursday the release of a newly developed, backwards-compatible, lossless MP3HD format. Thomson had a hand in developing the digital MP3 audio format, but unlike MP3, the MP3HD format is lossless, meaning none of the audio information is lost though the files will naturally be slightly larger in size. The MP3HD format is backwards compatible with the original MP3 format, which is compatible with lossless audio codecs including FLAC, HD-AAC and Windows Media lossless.

A spokesman for the company said regular MP3 players will be capable of reproducing the MP3HD file as a generic MP3 file, as the new format contains both the regular MP3 track and added information in the ID3 tag that has thus far kept data such as track name, album and artist information.

The new format supports bitrates between about 500Kbps to 900Kbps and the main disadvantage is the resulting file size, as a four-minute song encoded at the highest bit rate will take up about 26MB. Reducing the bitrate will shrink sizes down to about 18MB.

As for royalty fees to interested partners, Thomson charges 75 cents for each PC software decoder, and between $2.50 and $5 for each codec, while a hardware decoder is 75 cents and a hardware codec costs $1.25. Thomson had no announcements as to any hardware partners that have committed to supporting the new format, though expects to do so in the near future. Strong hardware support is seen as necessary if the format is to be adopted, however.

Users can visit either All4MP3 or MP3HD to download an encoder that will let them create MP3HD files from 16-bit, 44.1KHz-encoded stereo WAV files. They can then play back the new, higher quality MP3HD audio tracks thanks to a WinAmp plug-in for Windows. [via PCMag]