Manual: Frequently Asked Questions

From OpenMPT Wiki
Jump to navigation Jump to search

Audio and MIDI[edit]

OpenMPT does not output any sound[edit]

Check your sound device setup. A common problem are ASIO drivers that cannot share the audio interface, such as ASIO4All. If you use ASIO4All (or a WASAPI / WDM-KS driver in exclusive mode) and have another application running that makes use of that sound device (such as a web browser, instant messenger, media player, ...), OpenMPT will not emit any sound. In that case, switch to another sound driver in OpenMPT’s settings.

Vice versa, it is also possible that another program occupies the sound device in exclusive mode, for example using an exclusive WASAPI driver. In that case, this program restricts other applications from accessing the sound device.

While OpenMPT is active, all other programs are muted[edit]

This is for the same reason as above. If your ASIO or WASAPI driver works in exclusive mode, other programs cannot output any sound on the same sound device while OpenMPT accesses the device.

Can I use OpenMPT to interact with external MIDI gear?[edit]

To be able to record MIDI Input and send MIDI data to external gear, you first have to set up MIDI in OpenMPT.

MIDI Record icon

MIDI Input does not work[edit]

  • Have you clicked the MIDI Record icon? Hint: If you make frequent use of the MIDI record functionality, you may want to set the Enable MIDI recording when launching OpenMPT option in the MIDI setup options.
  • Verify that no other application is accessing the MIDI port. Standard MIDI drivers only allow one application at a time to access a MIDI port.
  • Verify that other applications do actually receive incoming MIDI data. More often than not, MIDI devices are not set up properly to send MIDI data to a computer. A light-weight application that can be used for checking is SendSX.

Can you add ReWire support to OpenMPT?[edit]

No. The ReWire technology is only licensed to companies. OpenMPT is not created by a company, but by a few individuals spread across the world.

Why do old modules and chiptunes sound muffled in OpenMPT?[edit]

Because OpenMPT uses a high-quality resampler by default, and the theoretical goal of a good resampling filter and the practical low fidelity of many old module samples do not mix very well.

OpenMPT must resample all samples to a common mix sample rate (which is typically 44.1 or 48 kHz). This resampling step can be done using filters (interpolation) of varying quality. A perfect filter would not add any frequencies to the output signal that were not in the input signal. But such a perfect filter does not exist, and OpenMPT instead offers several filters of varying quality and speed (higher quality filters stress the CPU more than lower quality filters).

If modules were only using high-quality samples that already contain enough high-frequency content, i.e. samples that are being played close at the mix sample rate, you could always just use OpenMPT’s highest-quality resampling filter and everything would sound bright and nice. However, many modules rather use samples that use a much lower sample rate, which means that these samples theoretically do not contain any high-frequency material. But when using a low-quality resampling filter (e.g. linear resampling, as it was used in many trackers in the 1990s), the cheap algorithm cannot prevent ghost frequencies (so-called aliasing) from occurring, so these low-quality samples end up sounding much brighter than they should in theory — this is a wanted effect in many legacy modules. On the other hand, using a high-quality resampling filter will suppress these aliasing frequencies better and the module will in return sound muffled.

This is why older modules and chiptunes typically sound better with “worse” resampling filters, while a high-quality module with good samples will sound better with OpenMPT’s best resampling filters. For Amiga module formats, you may enable the Amiga Resampler for accurate reproduction of the Amiga’s sound characteristics.

Pattern Editor[edit]

How can I change the length of a pattern?[edit]

In the Pattern Editor, either click the yellow question mark icon or the pattern number in the upper-left corner of the pattern (labelled #0 or similar) to open the Pattern Properties window. Note that this feature is not available for MOD and S3M files, you will have to use pattern break commands in those formats to shorten patterns.

How can I change the playback speed of a pattern?[edit]

You can use Tempo and Speed change commands to change the playback tempo of a pattern. The actual interpretation of those commands depends on the Tempo Mode that is used.

The input cursor automatically moves after I have entered a note[edit]

You have probably accidentally enabled edit step in the pattern editor. Setting the edit step to 0 will keep the cursor from advancing to the next pattern row.

There is a volume command in the pattern that I cannot delete[edit]

OpenMPT shows the default volume (that is, the volume at which the note is going to be played if it is not explicitly overridden by the user) next to notes as a semi-transparent volume command. Since this command does not actually exist in the pattern, it can also not be deleted. Display of the default volume can be disabled by unchecking the “Show default volume commands” option.

What do those +++ patterns do?[edit]

Actually, they do not do anything. They are just separators which you can use to keep your sequence tidy. You can for example add them after every few patterns to visually highlight a group of patterns. If such a pattern is encountered while playing, OpenMPT simply skips over it.

The pattern display is laggy during playback[edit]

If you have “Follow Song” enabled, but the pattern display scrolls only in coarse steps, you have probably set the update period too high. Try setting this value as low as possible. However, if it is too low, audio output might distort with MME drivers, in which case you have to lower the latency as well. Generally you want both your latency and update interval to be as small as possible, but the lowest possible values always depend on the available drivers and CPU power.

I want a score of my module music[edit]

OpenMPT does not natively support a staff view. However, you can export your work to MIDI and then use for example Frescobaldi or LilyPond to produce sheet music.

Pattern drawing is slow[edit]

OpenMPT normally optimizes pattern drawing to be very fast. However, these optimizations are turned off on Wine for compatibility reasons, which can slow down pattern drawing considerably. Similar issues can be observed on some multi-GPU setups on Windows. There is currently no solution for this problem.

Sample Editor[edit]

Where can I get samples?[edit]

Have a look at our top picks site for various interesting sample sources. The Waveworld and KIArchive collections in particular offer a fairly complete set of samples that covers most types of sounds you will need to get started.

How can I load just the left or right channel of a WAV file?[edit]

You can use the context menu in the sample editor to keep just one of the channel of a stereo sample, or to split the two channels into two separate samples.

You can also split up a WAV file into its individual channels by opening it as a module rather than a sample. Every channel is then loaded into a separate sample slot. This way, you can also load multi-channel WAV files with more than two channels.

I cannot load any AAC / MP4 / ... samples[edit]

OpenMPT supports various audio codecs through Media Foundation on Windows 7 and newer. On older systems and Wine, Media Foundation is not available.

On some Windows systems, Media Foundation may be supported but not installed. This most commonly applies to “N” editions (Windows without Media Player) and Windows Server. Depending on your Windows version, you can install one of the following packages to enable Media Foundation codecs:


How can I apply more than one plugin to a channel or instrument?[edit]

By chaining the output of one plugin to the input of another plugin. See next question:

How can I route the output of a plugin to another plugin?[edit]

It is possible to route the audio and MIDI output of a plugin to another plugin. To enable plugin chaining, choose a plugin from the “Output To” list in the plugin’s mix settings.

My plugin (jBridge, Synful Orchestra, ...) crackles and clicks[edit]

Some plugins do not like if the plugin host sends varying amounts of audio data to be processed by them. While sequencers usually always send the same amount of data to plugins to process, this is not the case with most trackers, including OpenMPT, Psycle and Renoise (if its static plugin buffer is disabled). If you encounter such a plugin, please notify the plugin authors of the problem so that they can make the plugin compatible with hosts like OpenMPT. Note that the problem in jBridge should have been fixed, so if you still experience it, try upgrading to the latest version.

Can I load 64-Bit VST plugins into OpenMPT?[edit]

Yes, OpenMPT comes with its own plugin bridge that can load 32-bit plugins into 64-bit OpenMPT and vice versa. OpenMPT will automatically use this plugin bridge when required, but it can also be enabled manually in the Plugin Manager to sandbox troublesome plugins.

After updating OpenMPT, all plugins stutter or freeze[edit]

This may happen when switching from running the 32-bit version of OpenMPT to 64-bit or vice versa. If you use lots of legacy 32-bit plugins, do not use 64-bit OpenMPT, as it will have to run all your plugins in a bridge process (sandbox), which is much slower than running plugins directly in OpenMPT.

When restarting playback, the remnants of VST effects and instruments are heard[edit]

This is not a bug in OpenMPT, but in the plugins. Traditional DAWs, unlike OpenMPT, do not stop rendering audio when pressing the stop button, so in those DAWs reverb tails and fading notes from plugins would fade out over time. OpenMPT, on the other hand, really stops any audio rendering until playback is resumed. It then asks those VST plugins to clear their playback buffers, but some plugins do not adhere to this request (probably because this situation is rarely observed in traditional DAWs), causing some leftovers from the previously playing notes to be heard.

Module Formats[edit]

Which module format should I use?[edit]

See the manual section on module formats.

My module sounds different when played in other trackers[edit]

Please read the hints on compatible playback.

When converting to MOD, all samples sound strange[edit]

The frequency of the middle-C is fixed to about 8 kHz in the MOD format. OpenMPT tries to compensate for that by transposing notes in the patterns. In some corner cases, this will fail. Also keep in mind that the MOD octave range is limited, so some samples might have to be downsampled before they can be transposed without loss of note information.

My files do not open in MikMod / FMOD / name your player here[edit]

Some less compliant module libraries will fail to load perfectly valid XM / IT files. You can try re-saving those files with Fasttracker 2 or Impulse Tracker if necessary, or just avoid using those libraries. Note that if you want to use an old Winamp version (5.666 or older) to play module files, you should use the OpenMPT input plugin for Winamp instead of the built-in one to be able to play those files.

Can you add support for SID / SNDH / AHX / other formats?[edit]

As a general rule of thumb, we will not add support for file formats that do not contain pattern data (like SID / SNDH), that require a bytecode interpreter for specific hardware (SID / SNDH), sample synthesis (AHX) or any other kind of chip emulation (SID / SNDH). These formats are way too different from how tracked music is handled internally by OpenMPT, and there are already far better solutions out there.

Why is the Amiga Resampler not available for my MOD file?[edit]

The Amiga Resampler is only available for MOD files that conform to Amiga hardware limitations. That is, the file should have exactly four channels, and pattern notes must not exceed the range C-4 to B-6. If a file contains too many E0x (Set Filter) effects, the Amiga Resampler is also deactivated as it is unlikely that they were intentionally placed to toggle the Amiga′s output filter.


Why is previously usable Feature X unavailable in the latest version of OpenMPT?[edit]

Over the years, various people have added features to the IT and XM format without considering that other trackers or players would not support them. Having new features is of course a nice thing, but they should not be hacked into existing file formats. That is why they are gradually removed from the IT and XM formats to be exclusively available in the MPTM format. Of course, these features are still available when importing an old IT or XM file made with previous versions of OpenMPT, but you cannot use them in newly created files.

Examples of previously supported features are Tempo Mode, Envelope Release Node, Pitch / Tempo lock, etc.. If you want to access those features, use the MPTM format. You can convert existing songs to this format using the Song Properties dialog.

Can I sell the music I have created with OpenMPT?[edit]

Yes, you are absolutely free to do whatever you want with the music you create with OpenMPT.

Is OpenMPT portable?[edit]

Yes, it can be configured to be fully portable.

Is it safe to run OpenMPT from a USB or network drive?[edit]

In general yes, but — as with any other software — you must not disconnect or remove the drive while OpenMPT is running. The operating system will avoid loading parts of OpenMPT’s executable into memory that are currently unused, but as soon as some previously unused part of the OpenMPT code is required to run, OpenMPT will crash. Running OpenMPT from a network drive is thus only recommended if the network connection is completely stable. Do not disconnect USB drives while OpenMPT is running on them.

Where can I get samples and plugins?[edit]

We have compiled a list of free samples and plugins where you can find several websites to download freebies from to get your production process started.

OpenMPT crashed but did not create a memory dump[edit]

Some crashes prevent OpenMPT from creating its own memory dump. In that case, you can open the task manager and right-click the crashed instance of OpenMPT.exe in the process list and select Create Dump File.

Alternatively, you can use ProcDump. Find out the PID of the crashed instance of OpenMPT.exe through tasklist.exe on the command prompt or by using the task manager (the PID column in the process list might be hidden by default), then run procdump PID. Note that you can also run procdump -e PID before the actual crash happened. If ProcDump has the chance of catching the exception, it will automatically write a crash dump then.

I found a module that does not sound right when played in a loop. Is this a bug?[edit]

Probably not! Many modules are not written with song looping in mind, so they will sound different (slower, faster, louder, quieter, …) on their second iteration. Some are even made specifically to sound different after they loop (e.g. a lead instrument that was not heard at first may be heard after the song looped once). That said, if you want to make sure that your own modules sound correct when played in a loop, you should reset at least the following properties on the first pattern if they ever change during the song: Tempo, speed, global volume, channel volume, channel panning, filter settings, and any plugin parameters modified through parameter automation (PC events or MIDI macros).