With "bitrate" he probably meant the amount of bits that audio data is encoded on the audio CD. Without knowing enough details about it the audio bitrate on an audio CD determines how much artificial noise will be generated due to (bad) interpolation. Generally audio encoded at 16bit 44,1kHz is good enough to be compared to CD audio. Audio encoded in this format has about 96dB SPL, meaning on a perfect recording, you'll be able to record a pin or needle falling on the floor, while at the same time you can record a 4 cylinder engine with hood opened revving up. Audio encoded at 24bit 44,1kHz is similar to audio DVD's, cinema audio, and studio audio. Audio encoded in this format, has a dynamic range of about 144dB SPL. In a recording like this you'll be able to record a needle falling to the floor, as well as standing 200 feet from an F16 jet airplane landing track, and recording a jet take off or land. Music recorded at 24 bit is the highest dynamic range of volume that a human could ever perceive. Music recorded at 32 bit is a much higher quality, often for use in the studio. Music and audio recorded at this bitrate are being recorded for processing the audio waves. Example: One of the most intensive of simple effects is a reverb. If a reverb is 16 bit, while regular audio encoded at 16 bit seems kind of flawless to us, a reverb is actually not only reverbing the 'nearly' perfect audio, but also the oversampling (the artifacts, the errors). A 16 bit reverb sounds cheap. A 24 reverb can still be perceived as a cheap reverb. A 32 bit reverb is the only reverb where the sound is interpolated so well, that audio artifacts are not audibly amplified (or repeated); thus the only reverb that sounds convincing is 32 bit. Reverb is one of the few effects, together with a phaser (and perhaps a chorus), as well as pitch up/down, where choosing a higher bitrate makes a lot of sense. Concerning MP3 bitrate, yes, this is the compression magnification in which audio is compressed. A lower bitrate results in a smaller filesize, with loss of quality from the input signal. Some codecs like WMA (in lower bitrates <48kbps), OGG(higher bitrates >88kbps), and AAC (across the whole spectrum), and flac (lossless, but usually comparable to >320kbps), can record higher quality data per same filesize, or, record same (or better) quality for a (way) lower bitrate setting. Those are considered better encoders than the age old MP3 format, which is over 15 years old and should be put to rest.

2011-04-28 08:27:57