[admin]

Someone sent a private message asking the best MP3 file encoding bit-rate to use when creating files that will be uploaded to the foro. I thought others might be interested in my answer, so I decided to post a revised version of it here.

In general, the higher an MP3 encoding bit-rate, the higher the sound quality listeners will hear. (That isn't unconditionally true in all cases, because of some complex technical issues, but the statement is generally true.) Also, the higher the encoding bit-rate, the larger the size of a resulting file. Considering only audio quality, it is best to use the highest encoding bit-rate that results in a file less 9MB in size, because there is 9MB foro upload file size limit.

However downloading time is another important consideration. It takes 30.79 minutes to download 9MB with a 56K dial-in modem under ideal (full-speed) connection conditions. Actual dial-in modem download times are nearly always longer than that (sometimes twice that long or more). Though the number of internet users with wide-band connections has been increasing, a significant number still use dial-in accounts, so it is important to keep files small if you want all visitors to be willing to download them.

These encoding guidelines show quality/file-size trade-offs for three popular MP3 stereo audio encoding bit-rates:

256Kb/s bit-rate
Approximates CD sound quality
Compresses to approximately 20% of wave file size.

128Kb/s bit-rate
Approximates FM broadcast radio sound quality
Compresses to approximately 10% of wave file size.

64Kb/s bit-rate
Approximates AM broadcast radio sound quality
Compresses to approximately 5% of wave file size.

-Bob

[Exitao]

It should also be pointed out that there are three common types of encoding for MP3s:

CBR - constant bit rate; the kbps is constant all the way through.

VBR - variable bit rate; the encoder determines what bit rate to use at which point, this way parts with less audio detail can have a very low bit rate (e.g.spaces between notes), and parts with much higher detail get a higher bit rate, making for a good compromise with compression:quality. 128kbps VBR can be smaller and better than than 128kbps CBR, especially for something like solo guitar.

ABR - average bit rate; is similar to VBR, but has hard upper and lower limits, so it's a compromise between CBR aqnd VBR.

CBR is the safest bet to work with any MP3 audio device (e.g. ipods and such), but now most players can handle any of the 3 and on WiMP, Winamp or any PC software player will handle them.