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Cassette to MP3 Converter

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  • bill rowe
    http://www.shopxscargo.com/product_catalogue/cat_product_details.asp?category_id=6&product_code=33289&sub_category_1_id=14&category=Audio No idea if these
    Message 1 of 13 , Jul 10, 2013
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      Cassette Converter

      http://www.shopxscargo.com/product_catalogue/cat_product_details.asp?category_id=6&product_code=33289&sub_category_1_id=14&category=Audio

      No idea if these would work well enough for recovering data from our old cassettes but I had never seen the idea before so I thought I would pass it on.  $19.98 at xs cargo in canada.
    • Egan Ford
      ... My experience with Apple II cassettes as MP3 has been not very successful. I am 100% successful with WAV or AIFF (uncompressed formats). I wrote a tool to
      Message 2 of 13 , Jul 10, 2013
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        > http://www.shopxscargo.com/product_catalogue/cat_product_details.asp?category_id=6&product_code=33289&sub_category_1_id=14&category=Audio
        >
        > No idea if these would work well enough for recovering data from our old
        > cassettes but I had never seen the idea before so I thought I would pass it
        > on. $19.98 at xs cargo in canada.

        My experience with Apple II cassettes as MP3 has been not very
        successful. I am 100% successful with WAV or AIFF (uncompressed
        formats).

        I wrote a tool to take Apple II binaries and disk images and convert
        to perfectly clean WAV files and then created a site so that from your
        browser or mobile phone you could download directly into memory or
        disk. I cannot think of any reason you could not do the same for ELF
        data.

        To recover old data from tapes I'd recommend a very good tape player
        and Audacity (freeware) to record it, then write a small C program to
        convert to binary.
      • joshbensadon
        Hi Egan, Off topic but are you familiar with Apple 2 DOS 3.2 (or earlier?). I m specifically looking for the 5/3 nibble routine. I already have the DOS 3.3
        Message 3 of 13 , Jul 11, 2013
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          Hi Egan,

          Off topic but are you familiar with Apple 2 DOS 3.2 (or earlier?).
          I'm specifically looking for the 5/3 nibble routine.

          I already have the DOS 3.3 (6/2 nibble routine).

          Thanks,
          Josh



          --- In cosmacelf@yahoogroups.com, Egan Ford <datajerk@...> wrote:
          >
          > > http://www.shopxscargo.com/product_catalogue/cat_product_details.asp?category_id=6&product_code=33289&sub_category_1_id=14&category=Audio
          > >
          > > No idea if these would work well enough for recovering data from our old
          > > cassettes but I had never seen the idea before so I thought I would pass it
          > > on. $19.98 at xs cargo in canada.
          >
          > My experience with Apple II cassettes as MP3 has been not very
          > successful. I am 100% successful with WAV or AIFF (uncompressed
          > formats).
          >
          > I wrote a tool to take Apple II binaries and disk images and convert
          > to perfectly clean WAV files and then created a site so that from your
          > browser or mobile phone you could download directly into memory or
          > disk. I cannot think of any reason you could not do the same for ELF
          > data.
          >
          > To recover old data from tapes I'd recommend a very good tape player
          > and Audacity (freeware) to record it, then write a small C program to
          > convert to binary.
          >
        • somaspack
          MP3 is lossy, maybe ok for music but bad for must-have bits. Scott
          Message 4 of 13 , Jul 11, 2013
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            MP3 is lossy, maybe ok for music but bad for must-have bits.

            Scott

            --- In cosmacelf@yahoogroups.com, Egan Ford <datajerk@...> wrote:
            >
            > My experience with Apple II cassettes as MP3 has been not very
            > successful. I am 100% successful with WAV or AIFF (uncompressed
            > formats).
          • Egan Ford
            ... No, but if you go to comp.sys.apple2 or http://www.applefritter.com/forum/84 and ask you ll get a rapid response. Heavy traffic in both places.
            Message 5 of 13 , Jul 11, 2013
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              > Off topic but are you familiar with Apple 2 DOS 3.2 (or earlier?).
              > I'm specifically looking for the 5/3 nibble routine.

              No, but if you go to comp.sys.apple2 or
              http://www.applefritter.com/forum/84 and ask you'll get a rapid
              response. Heavy traffic in both places.

              Alternatively you can try Beneath Apple DOS. DOS 3.1 - 3.3 is covered
              in there (http://asciiexpress.net/files/docs/).

              Cheers,

              Egan
            • joshbensadon
              HI Egan, Thanks! I ll go try applefritter. I ve already read Beneath Apple DOS . Very good book on the floppy disk software, but falls a little short in the
              Message 6 of 13 , Jul 12, 2013
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                HI Egan,

                Thanks! I'll go try applefritter.

                I've already read "Beneath Apple DOS". Very good book on the floppy disk software, but falls a little short in the ordering of the 5/3 nibbilizer. I also read "Understanding the Apple II" by Jim Sather. It does a fantastic job at explaining the hardware and Woz's floppy controller. Woz essentially built his own microcoded state machine.

                In "Beneath Apple DOS" they show you where to nibbilize the first 5 bytes but not the next 5, so you have to still "Guess" the pattern. Guessing isn't the sort of thing you like to do when writting code.

                But thanks again for the great advice!

                :)J


                --- In cosmacelf@yahoogroups.com, Egan Ford <datajerk@...> wrote:
                >
                > > Off topic but are you familiar with Apple 2 DOS 3.2 (or earlier?).
                > > I'm specifically looking for the 5/3 nibble routine.
                >
                > No, but if you go to comp.sys.apple2 or
                > http://www.applefritter.com/forum/84 and ask you'll get a rapid
                > response. Heavy traffic in both places.
                >
                > Alternatively you can try Beneath Apple DOS. DOS 3.1 - 3.3 is covered
                > in there (http://asciiexpress.net/files/docs/).
                >
                > Cheers,
                >
                > Egan
                >
              • Kevin
                ... MP3 is garbage for music too. ;)
                Message 7 of 13 , Jul 12, 2013
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                  > MP3 is lossy, maybe ok for music but bad for must-have bits.

                  MP3 is garbage for music too. ;)
                • Ray Sills
                  True, MP3 is lossy. But, that may not matter when you are trying to record or reproduce two tones that are frequency shift keyed to designate encode a
                  Message 8 of 13 , Jul 13, 2013
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                    True, MP3 is lossy. But, that may not matter when you are trying to
                    record or reproduce two tones that are frequency shift keyed to
                    designate encode a sequence of 1s and 0s. You certainly do not -
                    need- to "compress" (data reduce) the content for a 4K binary file.
                    Even using AIFF or WAV files won't create very large files, especially
                    by today's standards where 4K is the smallest size file stored on a
                    modern HD... at least on my iMac.

                    The FSK tones usually used are well in the normal voice frequency
                    (telephone quality) spectrum. And, the tape format is normally quite
                    tolerant of frequency variations caused by wow and flutter or off-
                    speed that might be expected in a cheap cassette machine. I know that
                    the RCA VIP used frequencies of 800 Hz and 2000 Hz to differentiate
                    the data 1s and 0s. The VIP tape format output 4 seconds of 2000 Hz
                    tone as a header to synchronize the tape read routines, followed by
                    2.5 seconds of varying tones per 256 byte block (page). Bytes always
                    start with a 1 start bit, followed by 8 data bits, and end with a
                    parity bit.. (odd parity).

                    So, my take on it is that while MP3 offers no huge advantage, it
                    should be OK for saving and loading data. That said, I have not tried
                    it, and it would be an interesting experiment to see how it might work
                    or not work.

                    73 de Ray



                    On Jul 11, 2013, at 3:38 PM, somaspack wrote:

                    > MP3 is lossy, maybe ok for music but bad for must-have bits.
                    >
                    > Scott
                  • bill rowe
                    My original thought was that this thing probably depended on pc software for the mp3 conversion and you could maybe get it to save a wav file instead for input
                    Message 9 of 13 , Jul 13, 2013
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                      My original thought was that this thing probably depended on pc software for the mp3 conversion and you could maybe get it to save a wav file instead for input to richard's conversion tool.

                      On 2013-07-13, at 12:45 PM, "Ray Sills" <raysills3@...> wrote:

                       

                      True, MP3 is lossy. But, that may not matter when you are trying to
                      record or reproduce two tones that are frequency shift keyed to
                      designate encode a sequence of 1s and 0s. You certainly do not -
                      need- to "compress" (data reduce) the content for a 4K binary file.
                      Even using AIFF or WAV files won't create very large files, especially
                      by today's standards where 4K is the smallest size file stored on a
                      modern HD... at least on my iMac.

                      The FSK tones usually used are well in the normal voice frequency
                      (telephone quality) spectrum. And, the tape format is normally quite
                      tolerant of frequency variations caused by wow and flutter or off-
                      speed that might be expected in a cheap cassette machine. I know that
                      the RCA VIP used frequencies of 800 Hz and 2000 Hz to differentiate
                      the data 1s and 0s. The VIP tape format output 4 seconds of 2000 Hz
                      tone as a header to synchronize the tape read routines, followed by
                      2.5 seconds of varying tones per 256 byte block (page). Bytes always
                      start with a 1 start bit, followed by 8 data bits, and end with a
                      parity bit.. (odd parity).

                      So, my take on it is that while MP3 offers no huge advantage, it
                      should be OK for saving and loading data. That said, I have not tried
                      it, and it would be an interesting experiment to see how it might work
                      or not work.

                      73 de Ray

                      On Jul 11, 2013, at 3:38 PM, somaspack wrote:

                      > MP3 is lossy, maybe ok for music but bad for must-have bits.
                      >
                      > Scott

                    • joshbensadon
                      ... Hi Ray, I feel the same way, but, like you, I have not experimented with it so I don t know for sure. I agree with your basic argument which is these
                      Message 10 of 13 , Jul 13, 2013
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                        --- In cosmacelf@yahoogroups.com, Ray Sills <raysills3@...> wrote:
                        >
                        > So, my take on it is that while MP3 offers no huge advantage, it
                        > should be OK for saving and loading data. That said, I have not tried
                        > it, and it would be an interesting experiment to see how it might work
                        > or not work.

                        Hi Ray,

                        I feel the same way, but, like you, I have not experimented with it so I don't know for sure. I agree with your basic argument which is these compilations are nothing more than ONE signal of two alternating tones. I can't see how MP3 can mess that up. Now here comes the big "BUT". The human ear is very forgiving, in fact, I'm sure we can still hear a song playing even after you turn off the audio (or are those just the voices in my head?). My point is, perhaps MP3 at some point starts adding new transitions on the signal? It might be convenient to skip a phase transition just to create a pattern. That skip might not be heard by the human ear, but apparently ELF ears are much keener.

                        It would definitely be a fun experiment, I will also conduct the same one here... some day. MP3 comes in different degrees of compression, so that will likely have an impact?

                        Up to now, I've heard the masses on line saying it doesn't work, so I have to bow to those pioneers that have already tried it.

                        :)J
                      • Egan Ford
                        ... The tones are not relevant, at least that is the case for the Apple II. All that is measured is the number of cycles between zero crossings. The default
                        Message 11 of 13 , Jul 13, 2013
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                          > True, MP3 is lossy. But, that may not matter when you are trying to
                          > record or reproduce two tones that are frequency shift keyed to
                          > designate encode a sequence of 1s and 0s.

                          The tones are not relevant, at least that is the case for the Apple
                          II. All that is measured is the number of cycles between zero
                          crossings. The default for the Apple II is 1000 Hz for a 0 and 2000
                          Hz for a 1. It's up to the programmer to count the cycles to
                          determine 0 or 1 (and there is always a + or - to consider).

                          > So, my take on it is that while MP3 offers no huge advantage, it
                          > should be OK for saving and loading data. That said, I have not tried
                          > it, and it would be an interesting experiment to see how it might work
                          > or not work.

                          I've download and used MP3s that work just fine with the Apple II,
                          OTOH the ones that I have created have been hit or miss (probably some
                          setting). I speculate that the lossy compression may alter the
                          waveform and skip some of the zero crossings. Depending on how
                          tolerant the programmer was with ranges for 0 and 1 may determine if
                          they work. The 1000 Hz/2000 Hz range is fairly tolerant to issues
                          with different tape players, volume, tape stretch, etc... so I agree
                          is might work.

                          For my asciiexpress.net project I created my own audio code using 6000
                          Hz/12000 Hz to up the default 1333 bps to 8000 bps (I also threw in
                          compression to get 2x more on average). On some machines I can push
                          the native rate to 9600 bps, but it does not work on all machines--I
                          think have reached the tolerances of the HW design. MP3 for this
                          higher frequency download code hasn't worked out. Between data
                          compression and using higher frequency the AIFF/WAV files are smaller
                          as well further reducing any advantage of MP3 size.

                          I think another issue I may have encountered with MP3 was the player
                          and how the player did the D2A. It's been about 2 years since I
                          explored MP3 as an option, but I recall getting different results with
                          different players. AIFF/WAV have universally worked. I didn't take
                          very good notes, I was just trying to get results.

                          Lastly, I wonder if taking an original tape with all of its analog
                          glory and doing tape to MP3 may work better. I wonder if that is how
                          most of the MP3s that have worked for me were created. I create my
                          own files as "perfect" waveforms using a tool I wrote to convert
                          binary code to audio. That audio when converted to MP3 was
                          problematic. Again it could just be my tight 8000-9600 bps
                          requirements. And again, poor note taking.

                          Cheers,

                          Egan
                        • bill rowe
                          asciiexpress.net is very cool. You can select any of a bunch of apple programs and stream them into the cassette port of your apple from your phone.
                          Message 12 of 13 , Jul 13, 2013
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                            asciiexpress.net is very cool. You can select any of a bunch of apple programs and stream them into the cassette port of your apple from your phone.


                            On 2013-07-13, at 7:12 PM, "Egan Ford" <datajerk@...> wrote:

                             

                            > True, MP3 is lossy. But, that may not matter when you are trying to
                            > record or reproduce two tones that are frequency shift keyed to
                            > designate encode a sequence of 1s and 0s.

                            The tones are not relevant, at least that is the case for the Apple
                            II. All that is measured is the number of cycles between zero
                            crossings. The default for the Apple II is 1000 Hz for a 0 and 2000
                            Hz for a 1. It's up to the programmer to count the cycles to
                            determine 0 or 1 (and there is always a + or - to consider).

                            > So, my take on it is that while MP3 offers no huge advantage, it
                            > should be OK for saving and loading data. That said, I have not tried
                            > it, and it would be an interesting experiment to see how it might work
                            > or not work.

                            I've download and used MP3s that work just fine with the Apple II,
                            OTOH the ones that I have created have been hit or miss (probably some
                            setting). I speculate that the lossy compression may alter the
                            waveform and skip some of the zero crossings. Depending on how
                            tolerant the programmer was with ranges for 0 and 1 may determine if
                            they work. The 1000 Hz/2000 Hz range is fairly tolerant to issues
                            with different tape players, volume, tape stretch, etc... so I agree
                            is might work.

                            For my asciiexpress.net project I created my own audio code using 6000
                            Hz/12000 Hz to up the default 1333 bps to 8000 bps (I also threw in
                            compression to get 2x more on average). On some machines I can push
                            the native rate to 9600 bps, but it does not work on all machines--I
                            think have reached the tolerances of the HW design. MP3 for this
                            higher frequency download code hasn't worked out. Between data
                            compression and using higher frequency the AIFF/WAV files are smaller
                            as well further reducing any advantage of MP3 size.

                            I think another issue I may have encountered with MP3 was the player
                            and how the player did the D2A. It's been about 2 years since I
                            explored MP3 as an option, but I recall getting different results with
                            different players. AIFF/WAV have universally worked. I didn't take
                            very good notes, I was just trying to get results.

                            Lastly, I wonder if taking an original tape with all of its analog
                            glory and doing tape to MP3 may work better. I wonder if that is how
                            most of the MP3s that have worked for me were created. I create my
                            own files as "perfect" waveforms using a tool I wrote to convert
                            binary code to audio. That audio when converted to MP3 was
                            problematic. Again it could just be my tight 8000-9600 bps
                            requirements. And again, poor note taking.

                            Cheers,

                            Egan

                          • jdripper
                            ... And _Beneath Apple DOS_ is flat-out wrong when they claim that there are clock bits between the bits of the nibble. The whole point of using GCR is that
                            Message 13 of 13 , Jul 15, 2013
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                              --- In cosmacelf@yahoogroups.com, "joshbensadon" <joshbensadon@...> wrote:
                              > I've already read "Beneath Apple DOS". Very good book on the floppy disk software, but falls a little short in the ordering of the 5/3 nibbilizer.

                              And _Beneath Apple DOS_ is flat-out wrong when they claim that there are clock bits between the bits of the nibble. The whole point of using GCR is that it is self-clocking, so it doesn't need to throw away half the bandwidth on clock bits the way that normal single-density (FM) encoding does. That's why Apple gets 13 or 16 256-byte sectors per track where competing systems using single density only got 10 256-byte sectors.

                              The 4+4 nibblization of the address mark contents is FM, a degenerate case of GCR.

                              Normal double-density (MFM) encoding is even more efficient that Apple's GCR, for a given channel bandwidth, but requires more hardware than the Apple design, and more precise discrimination of the time between flux changes. To be any good, MFM requires a phase-locked-loop for recovery. The state machine of the Apple floppy controller includes a crude state machine, but not good enough for reliable MFM.

                              For many years, hard drives usually used (1,7) or (2,7) RLL, which is a form of GCR that is even more efficient than MFM, but requires an even better data separator. Now most hard drives use even more complex coding than that.

                              Eric
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