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Wav 2 Cas of Salmon Run


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#26 Allan OFFLINE  

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Posted Sun Jun 24, 2018 2:13 PM

After making sure the cassette would load on my 410, I did number one and two with Space Chase.

 

Hopefully it helps. I will go back and try them on some of the cassettes that would not record well.

 

Allan

 

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#27 Kr0tki OFFLINE  

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Posted Tue Jun 26, 2018 2:13 AM

Great quality recording, zero problems when converting.
 

It would seem that developing a utility for recovering of data from cassettes and let others to use it is just a very small first step.
The second step is becoming an expert on tape restoration. The third step is using your own tool to restore the data in an expert manner.
 
What to say, Kr0tki? Amazing job with the A8CAS project and tape restoration in general!

Well, thank you, that's kind of you. Me being the most proficient user of A8CAS should not surprise anyone, considering I still haven't motivate myself to write detailed enough documentation for other to use ;-)
 

Does the existing Wav2Cas and similar software do a comparative analysis to detect and compensate for tape stretch?
 
Given that we're only dealing with 2 frequencies it shouldn't be something that's too hard to do.

This feature is not yet included in any CAS converter, but it's doable.

But in reality, in all those years I haven't yet encountered a tape that showed any symptoms of stretching. In the quite rare cases of warping, it was always caused by a problem with the tape deck. Considering that such recordings do not qualify for preservation purposes anyway, the best solution in such cases is to re-dump the tape using a better tape player. So, while this feature is on my to do list, its priority is very low.

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Edited by Kr0tki, Tue Jun 26, 2018 2:13 AM.


#28 Allan OFFLINE  

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Posted Tue Jun 26, 2018 7:39 AM

Thank you, again, Kr0tki.

 

Your cassette/CAS skills are amazing.

 

Allan



#29 80s_Atari_Guy OFFLINE  

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Posted Tue Jun 26, 2018 9:04 AM

I love reading this stuff. I have many old tapes on many different platforms (Including Synthesizers) and have always wondered how to do this reliably.

 

 

 

Given that we're only dealing with 2 frequencies it shouldn't be something that's too hard to do.

 

Are they still 2 distinct frequencies once they're converted to digital ? In the analogue domain, you would have 1 frequency for the recording, and one from a mechanical problem. In the digital domain, would software be able to tell which is which ?

Genuinely interested.



#30 Allan OFFLINE  

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Posted Tue Jun 26, 2018 5:31 PM

I re-recorded Player Generator after cleaning the pad and rewinding it with a pencil a few times. I was able to load the wav file into Altirra without a problem. 

 

Allan

 

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#31 Kr0tki OFFLINE  

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Posted Tue Jun 26, 2018 6:26 PM

Yup, the recording is good enough now. The warping has not been completely eliminated, as there remains some rapid speed fluctuation, and the overall pitch gets progressively lower the closer to the tape's end, but the issue not severe enough to pose a big problem. With some manual help, the conversion ended successfully.

The version number and date in the filename are taken from comments in the BASIC listing.

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#32 Kr0tki OFFLINE  

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Posted Tue Jun 26, 2018 6:33 PM

Are they still 2 distinct frequencies once they're converted to digital ? In the analogue domain, you would have 1 frequency for the recording, and one from a mechanical problem. In the digital domain, would software be able to tell which is which ?
Genuinely interested.

Not sure if there's some misunderstanding. Atari programs are stored on tape as a single sine wave with frequency alternating between two values, 5327 Hz and 3995 Hz, to represent digital ones and zeroes, respectively. Conversion to digital form does not destroy this signal.

#33 80s_Atari_Guy OFFLINE  

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Posted Wed Jun 27, 2018 4:05 AM

What I meant was, if you are getting a 2nd frequency from problems with the equipment, or the recording, would software (used to correct the recordings) recognize the two frequencies ?

Sorry if it sounded confusing, I was just interested. I do lots of VHS restoration, and when you capture VHS recordings, if you also capture noise (a separate frequency) once digital it's no longer noise, just pixels. So you can no longer separate the noise from the recording, only use plug-ins to smooth-over the noise which then slightly blurs the final recording.



#34 Kr0tki OFFLINE  

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Posted Thu Jun 28, 2018 5:40 PM

I'm still confused. The speed issues in the tape recorder do not introduce any second frequency into the signal. They cause the original sine wave to shift its frequency lower. That frequency shift can be determined algorithmically without much problem.

#35 80s_Atari_Guy OFFLINE  

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Posted Thu Jun 28, 2018 6:59 PM

I wasn't talking about tape speed, which I'm fully aware wouldn't introduce a second frequency. I was talking about hum, buzzing, noise, etc.. generated by the analogue audio equipment. The second frequency would be the hum, buzz, noise, etc..

 

Don't worry about it. I know what I was on about, and this is now way off topic.



#36 Allan OFFLINE  

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Posted Sat Jun 30, 2018 3:38 PM

I've been working on making some Flac recordings. Here's APX Downhill. I got the wav to load in Altirra.

 

Allan

 

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#37 Allan OFFLINE  

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Posted Sat Jun 30, 2018 5:43 PM

I made one of Buried Bucks and it seems to have some issues. Any suggestions by looking at the recording? I pencil-rewinded about five times but it still looks like it has issues. I did a couple more but they are over 50MB so I will have to post them somewhere else.

 

Allan

 

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#38 Fred_M OFFLINE  

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Posted Mon Jul 2, 2018 2:52 AM

Here is downhill.

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Edited by Fred_M, Mon Jul 2, 2018 2:53 AM.


#39 thorfdbg OFFLINE  

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Posted Mon Jul 2, 2018 7:11 AM

This feature is not yet included in any CAS converter, but it's doable.
 

 

Actually, this is included in my wav2cas converter. It automatically selects the filter pair that provides the best recognition rate, evaluating the recording with all possible filter pairs available. This is also necessary to a certain degree as tape speed (not so much tape stretching) varies over time.



#40 Allan OFFLINE  

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Posted Mon Jul 2, 2018 7:13 AM

Here is downhill.

Thanks, Fred_M.

 

Allan



#41 thorfdbg OFFLINE  

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Posted Mon Jul 2, 2018 7:13 AM

I wasn't talking about tape speed, which I'm fully aware wouldn't introduce a second frequency. I was talking about hum, buzzing, noise, etc.. generated by the analogue audio equipment. The second frequency would be the hum, buzz, noise, etc..

 

Don't worry about it. I know what I was on about, and this is now way off topic.

The wav2cas decoder, similar to the real-world decoder, depends on two band-pass filters. As long as the noise is additive, such noise will typically be filtered out by the band-pass filter pair anyhow, so it should not matter. It becomes more complicate if the nosie is of a different nature and interference creates alias frequencies in the same frequency range than the two tones.



#42 Allan OFFLINE  

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Posted Mon Jul 2, 2018 8:48 AM

My mistake. Ignore if anyone saw the previous post I made. Downhill works fine.

 

On another note. I just did Let's Play by PDI but it's a two-track program with voice. It's too big to post here so I will post it somewhere else and include a link.

 

Allan



#43 Allan OFFLINE  

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Posted Mon Jul 2, 2018 10:06 AM

I took some screen shots from Let's Spell.

 

http://www.atarimani...spell_2971.html

 

I just have to record the other side.

 

Allan



#44 Fred_M OFFLINE  

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Posted Mon Jul 2, 2018 1:28 PM

I made one of Buried Bucks and it seems to have some issues. Any suggestions by looking at the recording? I pencil-rewinded about five times but it still looks like it has issues. I did a couple more but they are over 50MB so I will have to post them somewhere else.

 

Allan

 

 

Between 2:01 and 2:02 there is a small drop in the audio. I cannot fix that, but maybe Kr0tki can. Also between 3:46 and 3:48 is a big audio loss. Looking at the audio, it is possible that the program ends at 3.46 and the rest is a different program. But I cannot check that, because the audio drop at 2:01 makes the file unreadable for me.

 

Your audio files are a bit low in volume by the way  ;)



#45 Allan OFFLINE  

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Posted Mon Jul 2, 2018 6:04 PM

 

Between 2:01 and 2:02 there is a small drop in the audio. I cannot fix that, but maybe Kr0tki can. Also between 3:46 and 3:48 is a big audio loss. Looking at the audio, it is possible that the program ends at 3.46 and the rest is a different program. But I cannot check that, because the audio drop at 2:01 makes the file unreadable for me.

 

Your audio files are a bit low in volume by the way  ;)

I had the audio out on my deck almost cracked to the highest and the input volume on Audacity at 93. I will turn them even more to see if that helps.

 

Allan



#46 Allan OFFLINE  

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Posted Mon Jul 2, 2018 7:29 PM

I made another copy of Buried Bucks after 'Pencil-rewinded' a few more times and turned up the volume.

 

Allan

 

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#47 Fred_M OFFLINE  

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Posted Tue Jul 3, 2018 4:42 AM

Here you are Allan,

 

This time success! As I expected, the part after 3.46 is a different recording (luckily!). I enhanced the volume in Audacity and now Buried Bucks is loading :-)

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#48 Allan OFFLINE  

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Posted Tue Jul 3, 2018 3:12 PM

Thank you again, Fred_M.

 

Allan



#49 Mclaneinc OFFLINE  

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Posted Wed Jul 4, 2018 3:44 AM

Hey Fred, the Downhill, tried on Altirra as I don't have a cassette for the real Atari and no easy way to even make a tape :)

 

 

I only tried XL mode and after the main boot and it got past the CLOAD and the run it gave a couple of errors...Just to save me looking, is it 800 mode or awkward about basic version?

 

Cheers...Normally I'd check but I seem to have a whirlwind life of looking after every one I know, love doing it but I'm busier than I can cope with :)



#50 Fred_M OFFLINE  

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Posted Wed Jul 4, 2018 8:41 AM

Hey Paul,

 

You are right. I CLOADed the program and it loading fine. I never saw that it tries to load a second stage. I will have to take a look at it, to see what it is trying to do.






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