4. MP3PRO mp3PRO is entirely based on traditional mp3 encoding a modified itself the biggest technological highlight is that SBR (Spectral Band Replication band replication), which is a new audio coding enhancement algorithms. It offers to improve the low rate of Under the performance of audio and speech coding possible. This method can be specified bit rate to increase the audio bandwidth or improve the coding efficiency, SBR's greatest advantage lies in low data rates to achieve a very efficient encoding. If the high data rate circumstances, SBR would be a rubber stamp. When the production of mp3PRO file, the audio encoder is divided into two parts. Part of the audio data in the low-frequency part of the separation, through the traditional mp3 encoding technology derived from the normal mp3 audio stream, this would make the mp3 encoder can focus on the low-frequency signal and thus obtain better compression quality , and the original mp3 player can also play mp3PRO files. Another part of malpractices to separate the high-frequency band signal is encoded and embedded into the mp3 stream, the traditional mp3 player will be ignored out, and the new mp3PRO player can be restored from a high-frequency signals, and the two be combined, full-bandwidth, high-quality sound. the official claim that the adoption of such technologies can make mp3PRO encoding rate of 64kbps and 128kbps for mp3 to deliver the same quality. Conventional decoder can still capture the signal stream in which decode the mp3 to the neglect of SBR signal flow, but effects and ordinary 64kbps of mp3 no different, the new mp3PRO decoder can decode all of the complete audio signal flow, of course, can also be Decoding traditional techniques encoded mp3. Low bit-rate performance of mp3PRO obviously higher than the mp3, and WMA, but it is hard to say who wins, according to some HI-FI enthusiasts evaluation, mp3pro seems slightly better than some. Because of high bit-rate MP3 technology has developed very mature, almost perfect, and has such good as Lame encoding engine, mp3pro is not the opponent.