OpenMPT Issue Tracker - Issues

0001772: Move MIDI output off audio thread

Sat, 18 Apr 2026 23:16:18 +0000

While working on [Beyond](https://sagamusix.de/download/beyond/) my ASIO driver was struggling due to the MIDI driver taking its time to process outgoing MIDI messages to seven different devices. I modified the MIDI code locally to run on a separate thread (one per device actually), but that solution is not quite in a merge-able state yet (there are still some random deadlocks when closing a module). But the direction is right and should be used for more stable MIDI output.

0001966: sizeof(chunk) in SetChunk() measures span object size instead of PluginChunk size on 64-bit

Fri, 17 Apr 2026 16:04:35 +0000

In DigiBoosterEcho.cpp:210 and SymMODEcho.cpp:244, the SetChunk() function uses sizeof(chunk) where chunk is a const ChunkData& (i.e. mpt::const_byte_span&). On 64-bit platforms, sizeof(mpt::const_byte_span) is 16 bytes, but the target m_chunk (PluginChunk) is only 8 bytes (verified by static_assert in the header).
This causes the condition chunk.size() == sizeof(chunk) to require 16 bytes of input data, and the subsequent memcpy(&m_chunk, data, chunk.size()) writes 16 bytes into an 8-byte struct, overflowing 8 bytes into adjacent class members.
The correct check should be chunk.size() == sizeof(m_chunk), which is already used correctly in RestoreAllParameters() in the same file (line 98).
Affected files:
- soundlib/plugins/DigiBoosterEcho.cpp line 210
- soundlib/plugins/SymMODEcho.cpp line 244
Note: On 32-bit platforms sizeof(span) may happen to equal sizeof(PluginChunk) (both 8), masking the bug.

0001964: Vst3Shell 1.4 not working in OpenMPT

Sat, 11 Apr 2026 22:15:44 +0000

I installed a plugin called Misstortion2, and installed it via the installer that you get when you download it from a website. It only comes in Vst3 and I found out OpenMPT doesn't support Vst3 after failing to load Misstortion2 directly. So I do some looking and decide to try Vst3Shell as it looks the simplest and easiest to use as I like keeping things minimal.
I have Misstortion2 installed to C:\Program Files\Common Files\VST3, and all of Vst3Shell's components installed to C:\Program Files\Common Files\VST3\vst3shell_v1.4, however when I add Vst3Shell to OpenMPT as a plugin (after scanning the vst3shell_v1.4 folder in OpenMPT for new plug-ins) the "Editor" button is grayed out and I can't open it or use it.
Nothing happens afterwards, I installed my plugins into what I believe is the standard location, I don't know what I'm doing wrong.

Thanks for the help, means a lot

0001962: VS code generation bug leads to crash in plugin editor

Wed, 08 Apr 2026 07:17:31 +0000

I'll try to use one plugin called 'SQ8L' and for some reason when I select the 2nd option on it on my PC and as soon as I press a button. It suddenly crashes and shows window I have a screenshot of.

0001929: Main toolbar spin buttons disappear when locking PC on Windows 11

Mon, 30 Mar 2026 16:22:22 +0000

This somehow doesn't happen on Windows 10, but I see it on Windows 11. After coming back to OpenMPT from the Windows lock screen, the main toolbar's spin buttons disappear. They re-appear when moving / adjusting the toolbar. This is new in OpenMPT 1.32 and doesn't happen when not setting the corresponding edit fields as buddy controls.

It would be nice if this could be fixed without having to back to not setting buddy controls, as this looks better and is more correct.

0001960: crash with read-only mptrack.ini

Tue, 24 Mar 2026 11:54:23 +0000

If simply upgrade OpenMPT Tracker to latest version and leave mptrack.ini from previous version , so OpenMPT Tracker not runing , process in task manager available , but work window does not appear

0001953: UltraTracker 16-bit sample loops clamped incorrectly

Sun, 22 Mar 2026 18:17:53 +0000

Hi )
In UltraTracker available bug , very short samples in this melody

0001957: libopenmpt API for MIDI output data

Sat, 21 Mar 2026 13:11:40 +0000

It might be desirable to, in addition to the rendered PCM output, provide access to realtime MIDI data that would be sent to external devices or unavailable plugins.

0001017: Tick boundary rendering (was: Provide access to next play position)

Sat, 21 Mar 2026 12:55:40 +0000

PoroCYon asked on IRC if it's possible to retrieve the next play position (row/pattern). We already have this information, but it is currently not exposed.

0001952: Retrigger note volume adjustment is not applied to MIDI velocity

Sat, 21 Mar 2026 11:34:04 +0000

As the title states, using Qxx with a value other than Q0x on a MIDI instrument does not impact the velocity of the outputted notes with each re-trigger.

0001951: Keep loop pattern on when using Space to play song

Wed, 11 Mar 2026 22:11:26 +0000

When using Space to play a track with Loop Pattern turned on, the loop keeps disabling. There's some more information here: https://www.reddit.com/r/OpenMPT/comments/1k16k60/comment/o1q6o7y/?context=1 - as explained, if using pause instead of stop, the loop pattern doesn't turn off, but there should be a way to force Loop Pattern to stay on persistently.

0000925: Support for external samples in libopenmpt

Mon, 23 Feb 2026 17:03:49 +0000

libopenmpt does currently not support sample data (or any other kind of data) outside the user-provided module file. There are several multi-file formats supported by OpenMPT:

* MPTM (external samples)
* MT2 (external samples)
* ITP (external instruments)
* Startrekker FLT/EXO modules (external synthesized instruments)
* Symphonie Pro (external samples)
* Face The Music (external samples)
* Graoumf Tracker 2 (external samples)
* SoundSmith (external samples)

In the future, we may also support:
* TFMX (external samples, no plans to support this format at the moment)
* Other formats

Apart from the fact that someone may simply want to play such modules using a libopenmpt-based player, there is also the possibility of someone wanting to use external samples e.g. for saving space when composing music for a game.

There are also security implications when accessing external files, and the feature should probably be opt-in (and possibly fully backwards-compatible with previous library versions, e.g. by using a ctl value for providing the module file path).

0001950: have an all modules (without wav and midi) and all supported files (including WAV and MIDI) selection seperately

Fri, 20 Feb 2026 20:31:17 +0000

for the module file open thing in openmpt add an option for all modules and seperately one for all files

like one option that covers all but also not wav and midi cuz i always have to manually filter them out �

0001530: CLAP plugin support

Mon, 16 Feb 2026 10:12:01 +0000

A new plugin format that several well-known plugin and host manufacturers want to commit to.

https://www.kvraudio.com/forum/viewtopic.php?t=574861
https://github.com/free-audio

0001366: LV2 support

Mon, 16 Feb 2026 10:12:01 +0000

LV2 support would be really nice. there are a lot of really good open-source plugins - and more being released all the time - that unfortunately i can't yet use with openmpt. presumably these would have better performance as well, being native code that doesn't have to go through wine?

i haven't seen an issue for this yet, so i figured it might as well be me.

0000783: cross-platform OpenMPT

Mon, 16 Feb 2026 09:27:09 +0000

This is a meta-issue, collecting various other issues related to making OpenMPT itself cross-platform.

0001559: Don't use WinAPI functions for INI reading/writing

Sun, 15 Feb 2026 09:10:06 +0000

Currently OpenMPT uses `ReadPrivateProfile*` / `WritePrivateProfile*`functions provided by Windows for reading and writing its settings files. This has several issues

- It's relatively slow, which is why we only write setting that we know have changed
- It requires hacks to enforce writing unicode files

As a consequence of the first point, it's possible that one OpenMPT instance takes a long time to shut down, and a newly launched instance may not see the settings as saved by the previous instance. One particularly worrying example is the following scenario:

1. Fresh OpenMPT installation, user sees the Welcome dialog and unchecks automatic update checks
2. User closes OpenMPT. This is the first time the INI file is written, so it takes quite a while to write out all settings.
3. User immediately reopens OpenMPT. It may now try to search for updates because the old instance might not have finished writing the settings yet.

A custom INI implementation should avoid this scenario. While the file is being written, other OpenMPT instances should wait until the file is no longer locked, rather than reading incomplete settings.

0001947: problem : Tracks melted on MIDI export when same instrument is played on several channels

Wed, 11 Feb 2026 19:58:28 +0000

Let's take a lead instrument, which generally in a vst is played legato, but this instrument has two voices which are splitted into two différent channels in a module file. When exported to MIDI, both channels of this same instrument will be in the same MIDI track, this is unworkable when this instrument has to be played legato.

User should be able to use an option, kinda like in the stream export feature, where, to be short, any instrument on any channel would generate a new track

0001946: Note-off events missing when exporting MOD or S3M to MIDI

Tue, 10 Feb 2026 21:31:36 +0000

Seems like some MIDI messages are missing in the latest versions of openMPT, particularly the "note off" message or something similar. the thing is extremely easy to reproduce and the same problem happened to any of the module files i've tried and it happens whichever the options I choose, just watch the capture I joined : on top is the track exported with openmpt1.31 : notes have a duration , on bottom is the track exported with openmpt 1.32.06 : all notes continue until next "note on on same key".

0001940: Higher quality sinc

Sat, 31 Jan 2026 18:18:12 +0000

Hi. The max level of sinc interpolation in OpenMPT is 8 points. It's not bad. But plenty of modern day DAWs can render 32-point sinc in real time, and even up to 512-point (or higher in some DAWs) in offline rendering. I think OpenMPT should catch up if the codebase allows it, and if it won't break too many things. I want the audio file renders that come out of the DAW to be as high quality as possible, with as few imaging artefacts as possible but still with as much frequency content as you can possibly pull out of the sometimes rather lo res samples in tracks from the 80s and 90s. r8brain interpolation for renders would also be a nice option, as it's already used in resampling of individual samples, and Reaper has it as an option for offline rendering of whole tracks.
Thanks in advance

0001943: Show hex and decimal for both volume and panning.

Tue, 27 Jan 2026 19:06:15 +0000

I just noticed this now, but panning is in decimal and not hex.

Instead of showing hex for volume and decimal for panning, why not show both hex and decimal for volume and panning? That way it would be more consistent and cleaner looking as well.

0001945: Most instrument editor shortcuts are not configurable

Tue, 27 Jan 2026 18:16:13 +0000

Since OpenMPT 1.32.01.00 all keyboard actions except "Duplicate Instrument" are missing from the "Instrument Editor" category of keyboard settings.

0001942: Parameter Control Events issue relating to VST's with paramaters that can go over the value of 999 .

Thu, 15 Jan 2026 13:00:30 +0000

You can set a higher parameter via the note properties menu, but it won't carry via copy-pasting.
Relates to plugins such as this one: https://dsp56300.wordpress.com/ostirus/

0001586: Skinning and/or Dark Mode

Thu, 08 Jan 2026 11:26:21 +0000

There's not too much to it, i just want dark mode, or maybe even being able to change the background colors without limitation instead of just black and white.

0001937: force non-UTF8 locale for OpenMPT

Wed, 07 Jan 2026 13:18:56 +0000

See <https://devblogs.microsoft.com/oldnewthing/20220531-00/?p=106697>.