View Issue Details

IDProjectCategoryView StatusLast Update
0001732OpenMPTPlayer input plugins (xmp-openmpt, in_openmpt)public2023-10-25 18:35
ReporterBluemax Assigned To 
Status newResolutionreopened 
Platformx86 / x64OSWineOS Version(version plz)
Product VersionOpenMPT / libopenmpt 0.7.3 (upgrade first) 
Summary0001732: Oktalyzer - Missing voice/notes (Grundlagen Demo Song.okt)

The Oktalyzer example song (Grundlagen Demo Song.okt) seems to be incorrectly rendered on in_openmpt. At least one voice is missing compared to Oldsk00l rendering. See attached video for comparison (bug occurs at song position 00:30s).

Arch Linux 6.5.6
Wine 8.17
Winamp v5.666 x86

Grundlagen Demo Song.okt:

Oldsk00l plugin for WinAmp:

TagsNo tags attached.
Attached Files
in_openmpt_oktalyzer_bug.7z (3,348,571 bytes)
Has the bug occurred in previous versions?yes
Tested code revision (in case you know it)


Saga Musix

Saga Musix

2023-10-11 17:25

administrator   ~0005787

Last edited: 2023-10-11 17:25

This isn't a bug, but a peculiarity how Oktalyzer's 8-channel mode works (paired channels require 7-bit samples but the sample playing on that channel is an 8-bit sample). You will also not hear that voice in Oktalyzer itself. I was in contact with an Oktalyzer user when I implemented this in OpenMPT (at his request, actually), and we both theorized why the demo song was released like that; Based on the name (Grundlagen = fundamentals), we think that it might be because it was supposed to teach the basics of how the program works, to show the user that 8-bit samples don't work on paired channels.

Saga Musix

Saga Musix

2023-10-11 18:14

administrator   ~0005788

Checking the video, I just realized you are referring to the other demo song, which doesn't have the paired channel issue. Instead, it uses Oktalyzer's extended arpeggio effects which are currently not supported by OpenMPT.



2023-10-11 21:01

reporter   ~0005789

I could finally manage to get the original Oktalyzer v1.57 up and running and i can confirm the corresponding voice has 'A57' effects.
So, as you already know the bug feel free to handle the ticket (keep/close).


Saga Musix

Saga Musix

2023-10-11 21:02

administrator   ~0005790

I'll keep it open as a reminder but it's unlikely that there will be an immediate fix (new effect commands need to be implemented).

Saga Musix

Saga Musix

2023-10-25 18:35

administrator   ~0005799

As of r19869, the missing arpeggio commands are worked around by transposing the notes in a way so that they still sound acceptable with standard MOD arpeggio. We may still add Oktalyzer-style arpeggios later, but this at least makes the track almost sound as intended. Test builds including this fix will be available from within a few hours.

I'll keep this issue open as a reminder to implement proper effect commands for this.

Issue History

Date Modified Username Field Change
2023-10-10 21:59 Bluemax New Issue
2023-10-10 21:59 Bluemax File Added: in_openmpt_oktalyzer_bug.7z
2023-10-11 17:25 Saga Musix Note Added: 0005787
2023-10-11 17:25 Saga Musix Note Edited: 0005787
2023-10-11 17:34 Saga Musix Status new => closed
2023-10-11 17:34 Saga Musix Resolution open => no change required
2023-10-11 18:14 Saga Musix Status closed => new
2023-10-11 18:14 Saga Musix Resolution no change required => reopened
2023-10-11 18:14 Saga Musix Note Added: 0005788
2023-10-11 21:01 Bluemax Note Added: 0005789
2023-10-11 21:02 Saga Musix Note Added: 0005790
2023-10-25 18:35 Saga Musix Note Added: 0005799