It's Like Faroudja for Compressed Audio
If you don't know what Faroudja processing does for video, it takes a lower bitrate video source de-interlaces it and reconstitutes it as a high-def, depending on the device, 480 or 720 progressive scan image with all the chunks smoothed out as far as the algorithm can work out. This works incredibly well, I can attest as I recently bought the InFocus ScreenPlay 4805 with Faroudja built in. Everything looks great on this projector, even old s-video input.
Anyway, that is Faroudja. The new thing is that a company called Coding Technologies has created an improved audio codec by combining old technologies like AAC which builds on MP3 by using MPEG4 instead of the old MPEG2 standard, which increases encoding efficiency with very little percieved loss, and proprietary technology called SBR and PS to achieve multi-channel capable compressed audio at excellent quality all the way down to 48kbps. I found out about this newer codec when I downloaded the new Winamp and saw that it supported AACPlus. I have only heard two or three songs encoded in this format, but they sounded outstanding. When listening to the new format, except for the fact that there were several channels, it was difficult to hear the difference between this and the songs I usually listen to, but then I noticed that the bitrate was 48kbps. Then it blew me away. I usually encode at 160, and I couldn't hear the difference here.
The proprietary stuff is the SBR and the PS. Parametric stereo is cool, it is like VBR but for stereo. Most of a stereo signal is really mono, so the encoder figures out what is the same between the channels, compressing it into a mono stream, while the differences are encoded separately. This greatly reduces the stream's footprint. I can tell you from listening that the quality is excellent. SBR is like the old Dolby HX Pro for tapes, but put to use in compressed audio. Everyone has heard MP3s that were overcompressed and had lost their high-end. SBR takes those recordings and with only a little encoding on the coder's end, can extrapolate and reproduce the highs. It too sounds really good. These technologies have me pretty excited about the future of compressed music. It would be awesome to be able to compress all my songs and have them fit into 10 GB instead of 40 GB. Check out the new Winamp if you are on a PC, and if you are on a Mac, pressure Apple to start using the new stuff!