Re: Robust tape decoders anywhere?

From: Groepaz (groepaz_at_gmx.net)
Date: 2003-05-19 08:52:46

On Sunday 18 May 2003 20:13, Marko Mäkelä wrote:
> I have some old Commodore 64 tapes from 1985 that are in rather bad
> condition. Few of the standard format programs can be loaded correctly, and
> it is hopeless to try to load any of the programs that are in the 64'er
> Turbo Tape format.
>
> Last December, I tried archiving these tapes with a modified 1530, where I
> rewired the internal card edge connector, so that a C2N232 device could be
> plugged in.  Tonight, I tried reading a couple of tapes with Andreas
> Andersson's TAPir program, which samples the audio from a sound card.  It
> didn't produce better dumps than those I already have.
>
> Are there any robust tape decoder tools that apply some sort of a search
> algorithm in order to read almost-unreadable tapes?  Do they require a
> loopback to the pulse detection algorithm, or can they work on pulse
> streams (TAP format)?

a) i take it that the head alignment is considered ok? in the old days i used 
a nice program from input64 for that stuff (very accurate, other than most 
other of these programs).... i am sure you checked that marko :) but there's 
however a small chance you can still improve it :)

b) i once rescued some old audio tascam "tapes" (4 track crap :=P) by playing 
and rerecording (sampling with the pc) them in 1/4 their original speed, and 
then averaging out the original data with a simple 4to1 cubic 
interpolation.... i could get rid of the one or other small pop this way. 
maybe this could be useful for you aswell... (i dont know how to let the 
datasette play the tape at exactly 1/2 or 1/4 speed though :=P)

gpz

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