Using Pulse Density Modulation for 8-bit PCM

[+scorpio_ny]

1 hour ago, ivop said:

Thanks. Here's a song that more clearly has a higher fidelity in 8-bits. On Altirra it definitely sounds better, but on real hardware I was not so sure. But I have terrible speakers, even normal Pokey doesn't sound that clear, so I was wondering what others with better hardware think.

 

More files are here: https://github.com/ivop/atarisid/tree/master/atarisid7/xex

 

 

as6s-cn.xex 7.01 kB · 1 download as7s-cn.xex 8.49 kB · 1 download

Hi @ivop,

 

Do these examples work with NTSC and PAL machines or does it only work with PAL?

 

[ivop]

42 minutes ago, scorpio_ny said:

Hi @ivop,

 

Do these examples work with NTSC and PAL machines or does it only work with PAL?

 

The emulation runs perfectly fine on NTSC, but I have not catered for 60Hz so the C64 player gets called 60 times per second, hence the songs play too fast. I might look into that later if there's demand. It's not that hard to wait a little longer than one frame on NTSC before calling the player again.

 

Edit: It just occurred to me that it might be that some players take too much CPU time and don't work on 60Hz.

Edited October 29, 2023 by ivop

[+MrFish]

1 hour ago, ivop said:

...hence the songs play too fast. I might look into that later if there's demand.

I'm interested in NTSC versions.

 

[ivop]

4 hours ago, MrFish said:

I'm interested in NTSC versions.

Try here: https://github.com/ivop/atarisid/tree/master/atarisid7/xex-ntsc

 

Have tested around ten of them (quick players and notoriously slow ones) and they all seem to play fine with altirra /ntsc foo.xex

 

Note that some songs fare better with only four levels of volume than others. I'm considering a rewrite that works with register dumps á la SAP-R but for SID, already massaged to values for the softsynth engine, and analyzed which waveforms it uses. So instead of including all possible combinations (like now) I can only include the waveforms that are needed and fill the rest of the memory with more waveforms for more volume levels and more granularity in the pulse waveforms. That should greatly improve some songs that are now a little meh...

Edited October 29, 2023 by ivop

[+MrFish]

39 minutes ago, ivop said:

Try here: https://github.com/ivop/atarisid/tree/master/atarisid7/xex-ntsc

 

Have tested around ten of them (quick players and notoriously slow ones) and they all seem to play fine with altirra /ntsc foo.xex

Thanks. Good to hear them at the right speed now.

 

I tried a handful on real hardware and they worked fine.

 

BTW, is there any way to download a whole directory on Github? I couldn't see any. I know there is on SourceForge (or at least always has been in the past; haven't done it recently).

 

[ivop]

11 minutes ago, MrFish said:

BTW, is there any way to download a whole directory on Github? I couldn't see any. I know there is on SourceForge (or at least always has been in the past; haven't done it recently).

If you mean an automatically generated tarball or zip file, there is none at github. But you can easily clone the whole repo with git clone https://github.com/ivop/atarisid

 

The official client: https://git-scm.com/downloads

Windows GUI clients: https://git-scm.com/downloads/guis

 

I believe TortoiseGIT is nice. Never used it myself though. I use the command line or the builtin git support of Qt-Designer or Visual Studio on Windows if I really have to.

 

EDIT: Oh, there actually is an automated zip file! https://github.com/ivop/atarisid/archive/refs/heads/master.zip

It's under the Code menu (green button).

 

Edited October 29, 2023 by ivop

[+MrFish]

5 minutes ago, ivop said:

If you mean an automatically generated tarball or zip file, there is none at github. But you can easily clone the whole repo with git clone https://github.com/ivop/atarisid

Thanks, that works.

 

5 minutes ago, ivop said:

The official client: https://git-scm.com/downloads

Windows GUI clients: https://git-scm.com/downloads/guis

 

I believe TortoiseGIT is nice. Never used it myself though. I use the command line or the builtin git support of Qt-Designer or Visual Studio on Windows if I really have to.

I'll check it out sometime.

 

[+scorpio_ny]

1 hour ago, ivop said:

Try here: https://github.com/ivop/atarisid/tree/master/atarisid7/xex-ntsc

 

Have tested around ten of them (quick players and notoriously slow ones) and they all seem to play fine with altirra /ntsc foo.xex

 

Note that some songs fare better with only four levels of volume than others. I'm considering a rewrite that works with register dumps á la SAP-R but for SID, already massaged to values for the softsynth engine, and analyzed which waveforms it uses. So instead of including all possible combinations (like now) I can only include the waveforms that are needed and fill the rest of the memory with more waveforms for more volume levels and more granularity in the pulse waveforms. That should greatly improve some songs that are now a little meh...

Thank you for NTSC version and link to the combined downloads. Makes it a lot easier.

 

By the way: any chance that some of the songs were written to support a stereo or quad pokey setup? I have Pokeymax installed in a couple of my systems and I am looking for music that really take advantage of this setup.