[Coco] [Color Computer] Re: Other WAV2CAS

[James the Animal Tamer]

> I had some tapes that wouldn't load so I started to look into 
writing
> a program to deal with it.

Yeah, I've had to do that for some systems for which none had 
previously existed, most notably the Panasonic JR-200U.

> Tape files are stored in blocks with headers, checksums, etc.

Yup.  Most systems use a simple checksum.  The Aquarius, 
unfortunately, has absolutely no quality-of-data check whatsoever.  
The VZ has one simple checksum over the whole file.  Most other 
systems store them in blocks and have a one byte simple checksum per 
block.  Damn, I wish they'd done a real 16-bit CRC.

> Most programs just try to load one save of a program and that's it 
or
> try noise reduction which can also kill the actual data.

Yup, done that, had to go back and massage the waves by hand to fix.

> A lot of the commercial tapes have multiple copies of the program
> stored on them.

Yup, usually I grab the tape and digitize both sides in both bays of 
my cassette deck, stereo.  Then I separate the tracks and process 
everything.  Then I compare the results, and the "most likely" which 
is consistent with the checksum, if any, is what I archive.

> The program loads the blocks from one save of the program, detects
> which blocks are bad and then loads another save and it combines the
> good blocks from the multiple saves.  As long as there are errors 
and
> more saves the program can attempt to recover more blocks.  If you
> have multiple tapes... it could even try from other tapes.

Yeah, I've been doing this procedure manually.  Works quite well;  
I've recovered everything for the Panasonic JR-200U except Winnie The 
Pooh's Lucky Letter Game.

> Those were the ideas anyway.

The problem facing me now is old copies of Alice cassettes (same tape 
file format as MC-10, which is close enough to CoCo format so that 
they can load each other's tapes).  And I do mean copies -- they were 
apparently copied by holding a microphone from a cassette recorder up 
to the speaker of a cassette player;  I can hear people talking in 
the background on some of the cassettes.  Attempting to load them 
gives me I/O error.  It's pretty crazy.  There's a "smart converter" 
for the Sinclair Specu... er, Spectrum;  I was hoping that the CoCo 
would have one too.  If not, I'll have to figure out where the 
problems are and massage the WAVs manually.  Time consuming!






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