Audip-tape archiving script

[Mike Keithley]

I have updated my audio-tape archiving script.  If you'd like a copy, reply
to this message privately.

This script was inspired by the wish to archive NLS books on CDs so that I
could get them back to the library faster and read them at leisure.  It's
also very handy archiving all those old NLS magazines I'd like to listen to
some time but haven't the space to store the tapes.

The script can:
1.  Handle one complete tape per session.

2. archive normal (Phillips) format (generating two sides) or NLS format
(generating four sides).  The side-names are dependent on the tape-number
being archived.  For example, the second cassette of a book generates
file names 05 06 07 and 08 with an extention dependent on the
output-file-format chosen.

3.  Output-format is currently mp3, wav or cdr.

4.  It can trim silence from the beginning and ends of files if the tape
isn't too noisy and there are no transients.

5.  Lets you set a low-pass filter cut-off so that the bassiness of some
tapes can be lessened.

6.  It can record at speed, twice-speed or four-time-speed meaning
that one pass of an NLS tape (assuming you can get your cassette deck to
run at 3-3/4 IPS) will take 24 minutes.

7.  Output can be set up for sampling from 16k to 128k in mp3 format or 16k to
44k for wav format.

8.  The System is menu-driven with help being part of most menus.

This scripts needs sox version 12.17.4 though earlier versions can be used
if the script is edited to include the pick effect.  It also needs the
lame encoder (I think the latest version is 3.91).

Because wav format is used internally, a considerable amount of disk-space
is needed--in the range so 800 megabytes for a c90 NLS tape
recorded at four-times-speed with output at 32k.  It will use less disk
space if you can tolerate slower sampling.  Temporary files are removed
when the script complete leaving only the output.

A good tape-deck for this kind of work is a "dubbing deck" where there are
two parts--a playback transport and a play/record transport.  Often this
kind of machine has a dubbing mode where the tapes run at two-times speed
(3-3/4 IPS).  This mode can be used by using a cassette shell meant as a
coupler to make a CD player work in a car-stereo that has a cassette-player.
These shells have a continuous loop of tape so the record/play portion of the
dubbing-deck is happy and you take the signal from the playing deck
(from the output jacks of the unit) to your
sound card.  For this to work well, your sound-card has to deliver
frequencies upwards of 20 kHz.