rad0,

Do you mean "bit-rate" when you mention resolution?  The bit-rate
determines how much memory an MP3 takes (plus the ID3 tags).  Basic formula
(for constant bit-rate) is:
Memory(bytes) = Length of song or voice clip (seconds) * bit-rate (kilobits
per second) / 8 (bits per byte).    Plus a few measly hundreds of bytes for
tags (ignoring all the evil new extensions like embedded images such as
album covers, embedded lyrics etc!)
E.g.  for a 5-minute song (300 seconds), encoded at 192kbps, you get
roughly (pedants forgive me if the "kilo" is 1024):
7,200,000 bytes = 300 * 192,000 / 8     i.e. about 7 MB (megabytes - note
that often hardware memory is specified in megaBITS, 8 times smaller than
you think!)
The same applies for ABR (see below).  With plain VBR you can't really
calculate how much memory you'll need, except for maybe an upper limit
(encoding can't ever go above 320kbps maximum MP3 bitrate, so calculate
above formula using that as a CBR and you've got absolute worst-case VBR
memory consumption!  But you can sometimes limit the upper bitrate of VBR
encoding too, so take that with a grain of salt.)

What is your application?  If you are recording voice, don't use MP3, use a
voice-specific codec.  If you are recording music, decide the quality you
want, and whether you will be recording using a constant bit-rate (CBR) or
variable bit-rate (VBR).  Average bit-rate (ABR) is VBR that's guaranteed
to take a similar amount of memory as an equivalent CBR encoding, but with
the quality advantages of VBR.  I can explain these further if you wish.
For reasonable quality music (non-archival quality!) use about 192kbps CBR,
or VBR.  Do you intend making / using a hardware encoder in realtime?  If
so, VBR or ABR might not be available.  Also note that the higher your
bitrate, the harder your hardware / software that buffers the output of the
encoder to your storage (memory, disk, whatever) has to work!

Er, have I said enough yet?  I'm happy to help with further info if I can.
Please note the capital "OT" in the subject-line too (for some people's
email filters).

Cheers,
-Dave.




                    rad0
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                    Sent by: pic         Subject:     [ot]: mp3 memory required per minute??
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                    12/06/01 08:05
                    PM
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hello,

I would like to know if anyone knows how much memory is required
per minute for using an mp3 recorder?

If you have any info on this, please let me know, and could you please
let me know the resolution of your mp3 recording?

Thanks

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