Help with broken BASIC blocks

jpablo

Hi,

Could anyone help me in recovering two broken BASIC blocks?:

http://webmail.unizar.es/upload/download.php?file=1247602759.invitado.php5kQ4az&name=Didacticiales-BadBlocks.voc.zip

They both belong to a Spanish MIA called Didacticiales (http://www.worldofspectrum.org/infoseekid.cgi?id=0023509) which is extremely difficult to find. The rest of the tape was successfully preserved.

There seems to be missing information, so it should be a matter of guessing what's lost...

Andrew Barker

Ah, I see there's a signal dropout at around 2:48.960 for around 21ms :-(.
Nuno is usually the master at recovering such things, he's helped us on a number of occasions.
If anyone can he can :-).

I assume no-one has a snapshot knocking around that we could potentially recover the data
from, or whether Side B contains anything ?

Cheers

Andy.

jpablo

First, thanks for your help, Andy :)

Andrew Barker wrote: »

Ah, I see there's a signal dropout at around 2:48.960 for around 21ms :-(.

Yes, there is :-(

Andrew Barker wrote: »

Nuno is usually the master at recovering such things, he's helped us on a number of occasions.
If anyone can he can :-).

Does he usually read the forums?

Andrew Barker wrote: »

I assume no-one has a snapshot knocking around that we could potentially recover the data
from, or whether Side B contains anything ?

There's no snapshot, I'm afraid, since it is a very rare commercial tape (just have a look at the inlay and you'll realise there must exist just a few of these).

Side 1 and side 2 are different, but the blocks I posted are the only ones that fail (due to signal dropouts). Block 1 belongs to side 1, and block 2 belongs to side 2. I just glued them together, just to make a lighter download :)

netraider

jpablo wrote: »

Does he usually read the forums?

I usually do ;)

This one seems like a good 'candidate' :D
Let's see what can be done..

zxbruno

Ahhh, I had no idea a fellow Portuguese helped with preservation efforts. :)

jpablo

Thank you very much, Nuno!

(fingers crossed) :-)

zxbruno

Juan, you could also ask McLeodIdeaFix at Speccy.org. He knows how to do these things with Soundforge.

andregiax

Hi ,
over 2:48.963
I found also data stream interruption at:

0:21.754
4:46.863

Bye

zxbruno

Is it completely interrupted? If there's low audio we might be able to raise the volume in those sections.

jpablo

Yep, I'm afraid it is. Or that's what it seemed to my untrained eye! ;)

Quickie

Dear all,

Below you'll find a new recording of didacticiales side-B:

http://rapidshare.com/files/247850919/Didacticiales-B.rar.html

Hope this could help to recover the missing info, but I'm afraid it will be a difficult job.

As I told to Juan, I tried to record it about 20 times, changing volume, frequency, applying filters... unfortunately with no success.
So it looks like that the tape is missing the pulses...

Best regards,

Ra?l

P.D: Felicidades Juan!! :D

netraider

Hey!

Back with some excellent news :)
Every byte has now been fully recovered, and another tape saved from oblivion!

I'm rewriting some of the text I've sent to jpablo earlier.

(boring bit follows)

After having some free time, I had a look at the first supplied VOC.
As there was only one small gap in the first basic block it was 'easily' fixable.

With the second one things wouldn't be so simple..
After closer study there were actually 7-8 corruptions in the audio. What's 'interesting' is that only 2 were actually silent gaps, the others seemed to be a case of a few bytes (5 or so) being clipped in each section. So, in order to reconstruct the block we would have to 'guess' those missing bytes.
I managed to find out most of the missing bytes (although they could not be 100% correct), but there were 2 (in the variables part) that would be very hard to recover.
At the time I wasn't sure how this happened, but it would be have been nice to have another recording made to be sure that the problem was in the source tape and not in the recording procedure.

Now, with this latest recording from Ra?l, everything was made clear!
The main problem with the missing bytes was actually in the recording process. Either that or the conversion from WAV to VOC..
There's still a gap in the recording, which was quickly fixed, but there are no cropped bytes in this second wav!
If only I had this to begin with, it would have saved me a few hours of work :roll:
Ra?l, your extra work paid up in the end ;)

So, expect to see this available to all soon on the next archive update.

Remember, never bin a mia or unlisted tape if you think it's beyond recovery...there's always hope that something can be done to resurrect it :)

NR

zxbruno

I also tried to magnify the bad sections and it looks pretty bad. :(
I hope you can find the author. :)

edit: Completely missed the above post. Nice!

Quickie

netraider wrote: »

Hey!

Back with some excellent news :)
Every byte has now been fully recovered, and another tape saved from oblivion!

I'm rewriting some of the text I've sent to jpablo earlier.

(boring bit follows)

After having some free time, I had a look at the first supplied VOC.
As there was only one small gap in the first basic block it was 'easily' fixable.

With the second one things wouldn't be so simple..
After closer study there were actually 7-8 corruptions in the audio. What's 'interesting' is that only 2 were actually silent gaps, the others seemed to be a case of a few bytes (5 or so) being clipped in each section. So, in order to reconstruct the block we would have to 'guess' those missing bytes.
I managed to find out most of the missing bytes (although they could not be 100% correct), but there were 2 (in the variables part) that would be very hard to recover.
At the time I wasn't sure how this happened, but it would be have been nice to have another recording made to be sure that the problem was in the source tape and not in the recording procedure.

Now, with this latest recording from Ra?l, everything was made clear!
The main problem with the missing bytes was actually in the recording process. Either that or the conversion from WAV to VOC..
There's still a gap in the recording, which was quickly fixed, but there are no cropped bytes in this second wav!
If only I had this to begin with, it would have saved me a few hours of work :roll:
Ra?l, your extra work paid up in the end ;)

So, expect to see this available to all soon on the next archive update.

Remember, never bin a mia or unlisted tape if you think it's beyond recovery...there's always hope that something can be done to resurrect it :)

NR

Wow!!! Excellent job Nuno!!

I'm sorry for not posting a second recording before and make you loose some valuable time :(

Anyway we have a happy ending here ;)

Best regards,

Ra?l

jpablo

Nuno, you're really a master! :-)

Thank you very, very, very much. Also lots of kudos to Ra?l for spending his time in so many re-recordings of the tape.

The TZX image will be available in the next SPA2 update. You can however download it now if you want to have a look:

http://webmail.unizar.es/upload/download.php?file=1246443742.invitado.phpqSjwXQ&name=Didacticiales.zip

The link will expire after a week.

PS: Ra?l, thanks for your greeting!

Ivanzx

Thanks for your effort guys ;)

Andrew Barker

Great teamwork folks ! Hats off to Nuno once again for coming to the rescue and everyone who played a part in recovering this.