OSARA: Open Source Accessibility for the REAPER Application

OSARA is a REAPER extension which aims to make REAPER accessible to screen reader users. It was heavily inspired by and based on the concepts of the abandoned ReaAccess extension. It runs on both Windows and Mac.



OSARA requires REAPER 6.44 or later. The latest stable release of the SWS/S&M EXTENSION is highly recommended, as OSARA supports several useful actions from this extension.

OSARA is tested with NVDA and VoiceOver screen readers during development. However, on Windows, OSARA uses Microsoft Active Accessibility (MSAA) and UI Automation (UIA) to communicate information, so it should work with any screen reader which supports this correctly.

Download and Installation

You can download the latest OSARA installer from the OSARA Development Snapshots page.


Once you have downloaded the installer, simply run it and follow the instructions.

Note that if you previously copied the OSARA extension into REAPER's program directory manually (before the installer became available), you must remove this first. The installer installs the extension into your user configuration, not the program directory.

If you wish to completely replace your existing key map with the OSARA key map (recommended to make sure you have the most recent mappings), answer yes when prompted. If the installer does replace the key map, a safety backup of your existing key map will be made in Reaper's KeyMaps folder.


Because OSARA is an extension (not a standalone application) and also needs to install a key map, the installation process is a little different to most Mac applications. Please follow these instructions to install it:

  1. Open the OSARA disk image file you downloaded.
  2. Open the "Install OSARA.command" file. On macOS Catalina and later, you have to choose open from the context menu, accessed with VO+Shift+M.
  3. Follow the instructions. If you wish to replace the existing key map with the OSARA key map (which is recommended), answer yes when prompted. A backup of your existing key map will be made in Reaper's KeyMaps folder.
  4. The installer leaves a terminal window open. It can be closed with Command+Q.
  5. Press Command+E to eject the disk image.

Key Map

Even if you chose not to replace your existing key map with the OSARA key map, the OSARA key map will be copied into your REAPER "KeyMaps" folder so you can import it manually from the Actions dialog later if you wish. This is particularly useful if you wish to merge new additions with your existing key map, rather than replacing it. Note that all keyboard commands described in this document assume you are using the OSARA key map.

For users who previously used ReaAccess, the OSARA key map is similar to that provided by ReaAccess, though there are some differences. You can see the full key map by selecting Key bindings and mouse modifiers from the Help menu.

Additional Documentation

The sections below document all functionality specific to OSARA. However, they do not attempt to explain how a screen reader user can best understand and use REAPER. REAPER is a fairly complex application and most of the existing documentation is very much targeted at sighted users. For more complete, in-depth documentation and guides on using REAPER with OSARA, please consult the REAPER Accessibility Wiki.


Supported REAPER and Extension Actions

OSARA supports reporting of information for the following actions. Most of these are actions built into REAPER, but a few are useful actions from the SWS extension.

Track Navigation/Management

Adjusting Track Parameters

Edit Cursor Movement




Markers and Regions

Time Signature/Tempo Markers










Project Tabs


Alternative Key Map Layers (requires Reaper 7.0 or newer)

MIDI Editor

Media Explorer

Context Menus

There are several context menus in REAPER, but some of them are difficult to access or not accessible at all from the keyboard. OSARA enables keyboard access for the track input, track area, track routing, item, ruler, envelope point and automation item context menus.

To open the context menu for the element you are working with, press the Applications key or Shift+F10 on Windows, or Control+1 on Mac. For example, if you have just moved to a track, it will open the track input context menu for that track. If you have just moved the edit cursor, it will open the context menu for the ruler.

For tracks, there are three context menus:

  1. Track input: Allows you to set the input to use when recording, etc. You access this by pressing the Applications key or Shift+F10 on Windows, or Control+1 on Mac.
  2. Track area: Provides options for inserting, duplicating and removing tracks, etc. You access this by pressing Control+Applications or Control+Shift+F10 on Windows, or Control+2 on Mac.
  3. Routing: Allows you to quickly add and remove sends, receives and outputs without opening the I/O window. You access this by pressing Alt+Applications or Control+Alt+Shift+F10 on Windows, or Control+3 on Mac.

Parameter Lists

OSARA can display a list of parameters for various elements such as tracks, items and effects. You can then check and change the values of these parameters. This is useful for parameters which are tedious or impossible to access otherwise.

Track/Item Parameters

To access the parameter list for a track or an item, select the track or item you wish to work with. Then, press Alt+p (OSARA: View parameters for current track/item/FX (depending on focus)).

FX Parameters

Many effects are unfortunately either partially or completely inaccessible. However, most effects make their parameters available for automation in a standard way. This can also be used to make them at least partially accessible. Thus, the FX parameter list is particular useful and is the only way to access some effects.

To access it:

  1. Select a track or item that has at least one effect instantiated. Then, press P (OSARA: View FX parameters for current track/take).
  2. Alternatively, to access FX parameters for the master track, press Shift+P (OSARA: View FX parameters for master track).
  3. If there is more than one effect instantiated on the track or item, OSARA will present choices in a menu that you can navigate with Up and Down arrows. Hit Enter on the desired effect to reach its parameters. If there are input or monitoring FX instantiated on the track, these will also be included in the menu with an appropriate suffix.

You can also access the FX parameter list from the FX chain dialog. To do this, select the effect in the FX chain list box and then press Alt+P (OSARA: View parameters for current track/item/FX (depending on focus)).

Note that some effects expose easily readable values, while others expose only percentages. When effects do expose easily readable values, these will be reported when focus is on the slider. The editable text is an internal number and probably won't correspond to the readable value on the slider.

Using Parameter Lists

Once you have opened a parameter list dialog, you can select a parameter from the Parameter combo box and check or adjust its value using the Value slider. For parameters which support it, there is also an editable text field which allows you to edit the value textually.

For a few parameters, there is a context menu with additional options related to the parameter. You access this using the More button after the value slider, which will only be available if the parameter provides a context menu. Alternatively, on Windows, you can press the Applications key or Shift+F10 while on the Parameter combo box or Value slider.

The Filter field allows you to narrow the list to only contain parameters which include the entered text. For example, if the full list contained "Volume" and "Pan" parameters and you type "vol" in the Filter field, the list will be narrowed to only show "Volume". Clearing the text in the Filter field shows the entire list.

As an alternative to using the Parameter combo box, you can press control+tab or control+shift+tab anywhere in the dialog to move to the next or previous parameter, respectively.

Some effects expose a lot of unnamed parameters which can make finding useful parameters challenging. The Include unnamed parameters check box may help with this. When unchecked, unnamed parameters are excluded from the parameter list. Currently, this means parameters with completely empty names, the single character "-", a name like #001 or a name like P001.

When you are done working with parameters, press the Close button. Alternatively, you can press enter or escape.

Reading Current Peaks

OSARA allows you to read the current audio peak for channels 1 and 2 of either the current or master tracks. You do this using the following actions:

Peak Watcher

Peak Watcher allows you to be notified automatically when a level exceeds a specified value. It can also hold the level until it is manually reset or for a specified time, allowing you to catch peaks that might otherwise be missed when manually checking the current peak. Two "watchers" are provided, enabling you to watch two different levels and configure settings independently. Beyond simple peak levels, various types of levels are supported for tracks and track effects, including LUFS, RMS and gain reduction.

To use Peak Watcher:

  1. Navigate to the track or track effect you want to watch. To watch a track effect, open the FX chain for the track and select the desired effect.
  2. Press Alt+w (OSARA: Configure Peak Watcher for current track/track FX (depending on focus)).
  3. From the context menu, choose which of the two watchers you want to configure. If a watcher is already configured, information about the configuration will be included in the menu. Choosing a watcher which is already configured will reconfigure the watcher for the track or effect you focused in step 1.
  4. From the Level type combo box, select the type of level you want to use: peak dB, several LUFS options, loudness range LU, several RMS options, true peak dBTP or gain reduction dB.
  5. Peak dB is measured post-fader.
  6. The LUFS, RMS and true peak options use the JS: Loudness Meter Peak/RMS/LUFS (Cockos) effect, which is included with REAPER. OSARA will add the effect to tracks automatically and remove it when it is no longer required. These levels are measured pre-fader due to the reliance on the JS effect.
  7. Gain reduction is only supported for track effects which expose this information.
  8. If you are watching a track, you can check the Follow when last touch track changes option to watch whatever track you move to in your project.
  9. If you want to be notified when the level of channels exceeds a certain level, in the "Notify automatically for channels:" grouping, check the options for the desired channels and enter the desired level.
  10. The Hold level grouping allows you to specify whether the highest level (or lowest level for some level types) remains as the reported level and for how long. Holding the highest/lowest level gives you time to examine the level, even if the audio level changed immediately after the highest/lowest level occurred. There are three options:
  11. disabled: Don't hold the level at all.
  12. until reset: Hold the level until the Peak Watcher is reset.
  13. for (ms): Allows you to specify a time in milliseconds for which the level will be held.
  14. Press the Reset button to reset the reported peak levels if they are being held.
  15. When you are done, press the OK button to accept any changes or the Cancel button to discard them.
  16. Alternatively, you can press the Disable button to disable this watcher. If you have configured another watcher, that watcher will continue to watch levels.

At any time, you can report or reset the levels for either of the watchers using the following actions:

You can also quickly pause Peak Watcher using OSARA: Pause/resume Peak Watcher. While paused, Peak Watcher won't notify you of any level changes. You can later use the same action again to resume automatic reporting.

Peak Watcher settings are saved with the project. To configure default settings to use for new projects, you can save them in a project template and configure this template to be used as the template for new projects in the Project section of REAPER Preferences.

Shortcut Help

It is possible to have REAPER list all shortcuts and to search for individual shortcuts in the Action List. However, it is sometimes convenient to be able to simply press a shortcut and immediately learn what action it will perform. This is especially useful if you have forgotten an exact shortcut but do have some idea of what it might be. You can achieve this using OSARA's shortcut help mode.

You can turn shortcut help on and off by pressing F12 (OSARA: Toggle shortcut help). While shortcut help is enabled, pressing any shortcut will report the action associated with that shortcut, but the action itself will not be run. In addition, OSARA will report any MIDI notes received via a MIDI input if the current track is armed. Note that OSARA cannot prevent MIDI notes from being handled, so if you're recording, any notes received will still be recorded.

Noncontiguous Selection

Usually, selection is done contiguously; e.g. you might select tracks 1 through 4. Sometimes, it is desirable to select noncontiguously; e.g. you might want to select tracks 1, 3 and 5.

You can do this as follows:

  1. Move to the track or item you want to start with.
  2. Optionally, select some other contiguous tracks or items.
  3. Press Shift+Space (OSARA: Enable noncontiguous selection/toggle selection of current track/item) to switch to noncontiguous selection.
  4. Move through tracks/items leaving other tracks/items selected; e.g. using Shift+DownArrow and Shift+UpArrow to move through tracks. These tracks/items will not be selected automatically as you move over them, but any previously selected tracks/items will remain selected.
  5. When you reach a track/item you want to select, press Shift+Space (OSARA: Enable noncontiguous selection/toggle selection of current track/item). You can also use this if you want to unselect a previously selected track/item.

Selection will automatically revert to contiguous selection the next time you move to a track/item without leaving other tracks/items selected.

If you want to select noncontiguous items on several different tracks, the procedure is exactly the same. However, it's important to remember that you must move between tracks without affecting the selection; i.e. using Shift+DownArrow and Shift+UpArrow. Otherwise, selection will revert to contiguous selection.

Accessing Controls for Sends/Receives/Outputs in the Track I/O Window

In the Track I/O window, there are various controls for each send, receive or hardware output. Unfortunately, these controls cannot be reached with the Tab key and it is tedious at best to access these with screen reader review functions.

When you tab to the Delete button for a send/receive/output, the name of the send/receive/output will first be reported. You can then press the Applications key or Shift+F10 to access a menu of additional options.

Manually Moving Stretch Markers

REAPER includes actions to snap stretch markers to the grid. However, sometimes, this is not sufficient and it is useful to be able to manually move stretch markers to a specific position.

To do this:

  1. Select the desired item.
  2. Go to a stretch marker; e.g. using Control+' (Item: go to next stretch marker). Ensure that OSARA reports the stretch marker.
  3. Move the edit cursor to the position to which you wish to move the stretch marker.
  4. Press Control+Alt+M (OSARA: Move last focused stretch marker to current edit cursor position).

Accessing FX Plug-in Windows

Some FX plug-ins can be controlled with keyboard commands, but you can't reach them by tabbing through the FX Chain dialog. In these cases, you can press F6 when focus is in the FX chain list to have OSARA attempt to focus the plug-in window.

Automation Items

An envelope can contain one or more automation items positioned along the timeline. With OSARA, you move to automation items as follows:

  1. Select an envelope using Alt+L or Alt+Shift+L (OSARA: Select next track/take envelope (depending on focus)).
  2. Now, use the normal item navigation commands; i.e. Control+RightArrow and Control+LeftArrow (Item navigation: Select and move to next item, Item navigation: Select and move to previous item). Multiple selection is also possible using Control+Shift+RightArrow and Control+Shift+LeftArrow (OSARA: Move to next item (leaving other items selected), OSARA: Move to previous item (leaving other items selected). Noncontiguous selection is done the same way described above for tracks and items.
  3. The item navigation commands will revert back to moving through media items (instead of automation items) when focus is moved away from the envelope. For example, moving to another track and back again will again allow you to move through the media items on the track.

Once you move to an automation item, the commands to move between envelope points such as Alt+K and Alt+J (OSARA: Move to next envelope point, OSARA: Move to previous envelope point) move between the points in the automation item. The points within an automation item can only be accessed after moving to that automation item; they cannot be accessed from the underlying envelope. To return to the points in the underlying envelope, simply move focus back to the envelope by selecting it again with Alt+L or Alt+Shift+L (OSARA: Select next track/take envelope (depending on focus), OSARA: Select previous track/take envelope (depending on focus)).

Notes and Chords in the MIDI Editor

In the MIDI Editor, OSARA enables you to move between chords and to move to individual notes in a chord. In this context, a chord is any number of notes that are placed at the exact same position. If there is only one note at a given position, it will be treated as a chord.

You move between chords using the Left and Right arrow keys (OSARA: Move to previous chord, OSARA: Move to next chord). When you move to a chord, the edit cursor will be placed at the chord and the new position will be reported. The notes of the chord will be previewed and the number of notes will be reported. The notes in the chord are also selected so you can manipulate the entire chord. For example, pressing Delete will delete the chord.

Once you have moved to a chord, you can move to individual notes using the Up and Down arrow keys (OSARA: Move to previous note in chord, OSARA: Move to next note in chord). When you move to a note, that note will be previewed and its name will be reported. The single note will also be selected so you can manipulate just that note. For example, pressing Delete will delete only that note.

When a chord or a note within a chord is being previewed, you can cancel the note preview by pressing the Control key.

You can select multiple chords or multiple notes in a chord. To do this, first move to the first chord or note you want to select. Then, use Shift+DownArrow or Shift+UpArrow to add the next or previous chord or note to the selection. For example, if you've moved to a chord and also want to add the next chord to the selection, you would press Shift+RightArrow.

Noncontiguous selection is also possible. You do this in the same way described above for tracks and items. That is, press Shift+Space (OSARA: Enable noncontiguous selection/toggle selection of current chord/note) to switch to noncontiguous selection, move to other chords/notes with Shift+Arrows and press Shift+Space to select/unselect the current chord/note.

Note Preview in the MIDI Event List (Windows Only)

When the MIDI Editor is set to Event List mode, REAPER presents a list with all the events in the current MIDI item. When a note gets focus in the list, OSARA will play a preview of the focused note. To cancel a note preview, press the Control key.

Navigating FX Presets Without Activating Them (Windows Only)

REAPER's FX preset combo box doesn't allow keyboard users to move through presets without activating them. Sometimes, you need to be able to examine or search the available presets without activating each one. OSARA provides a dialog to facilitate this.

You activate this dialog by pressing Alt+DownArrow when focused on REAPER's FX preset combo box. The dialog displays the preset list and allows you to navigate without presets being automatically activated. The Filter field allows you to filter the list to show only presets containing the entered text. Pressing the OK button activates the preset that's currently selected in the list.


OSARA provides a Configuration dialog to adjust various settings. You can open this dialog by pressing Control+F12 or Control+Alt+Shift+P (OSARA: Configuration).

The dialog contains the following options:

When you are done, press the OK button to accept any changes or the Cancel button to discard them.

There is also an action to toggle each setting; e.g. OSARA: Toggle Report position when scrubbing. These do not have keyboard shortcuts mapped by default, but you can add shortcuts in the Actions dialog (hit F4 to go there).

Although there is no option in this dialog to configure whether OSARA should automatically check for updates when REAPER starts, OSARA respects the setting for REAPER updates. You can configure this via the "Automatically check for new versions of REAPER on startup" option in the General section of REAPER Preferences.

Miscellaneous Actions

OSARA also includes some other miscellaneous actions.

Main section of actions list

Midi Editor section of actions list

MIDI Event List Editor section of actions list

Actions that report, but are not directly mapped to keyboard shortcuts

OSARA will report any native REAPER or SWS toggle action that exposes its state with a generic reporting style. The actions listed in this section are ones where some effort has been made for reports to be more dynamic, or productivity has been refined in some way. While these actions aren't directly on the key map, typically they're used as part of providing context sensitive workflows, custom or cycle actions instead. This list is worth referencing when making your own key map additions, assigning actions to control surfaces where reporting is desirable or assembling custom actions, as everything included here should report productively.

Unmapped in Main section

Unmapped in MIDI Editor section

Unmapped OSARA actions

Muting OSARA Messages in Custom/Cycle Actions

The action "OSARA: Mute next message from OSARA" can be used in custom/cycle actions to mute OSARA feedback for the next action. It should be placed before each action to be muted. If using this as part of custom actions that you'll be distributing, please test thoroughly to ensure that its placement won't suppress important reports.


If you need help, please subscribe to the Reapers Without Peepers discussion group and ask your questions there.

Reporting Issues

Issues should be reported on GitHub.


This section is for those interested in translating OSARA into their language.

OSARA can be translated using gettext PO files. If a REAPER language pack is installed, OSARA will attempt to load a translation based on the name of the REAPER language pack. OSARA can only load PO files in the UTF-8 encoding.

Translations are managed on Crowdin. With Crowdin, you can translate entirely online on the web, upload and download translations as .po files or directly sync your translations using Poedit.

If you'd like to translate OSARA, you will first need to sign up for a Crowdin account. Then, please file a GitHub issue and include these details:

If you'd like to test your translation before it is included in OSARA, you can copy it into the osara/locale folder inside your REAPER resource folder . If you don't know where the REAPER resource folder is, use the Show REAPER resource path action in REAPER. The file should be named with the same name as the REAPER language pack you are using, but with a .po extension. For example, if you have installed German.ReaperLangpack, rename the file to German.po. You will need to restart REAPER for any translation changes to take effect.


This section is for those interested in building OSARA from source code.

Getting the Source Code

The OSARA Git repository is located at https://github.com/jcsteh/osara.git. You can clone it with the following command, which will place files in a directory named osara:

git clone --recursive https://github.com/jcsteh/osara.git

The --recursive option is needed to retrieve Git submodules we use. If you didn't pass this option to git clone, you will need to run git submodule update --init. Whenever a required submodule commit changes (e.g. after git pull), you will need to run git submodule update. If you aren't sure, run git submodule update after every git pull, merge or checkout.


To build OSARA, you will need:


Mac OS

How to Build

To build OSARA, from a command prompt, simply change to the OSARA checkout directory and run scons. The resulting installer can be found in the installer directory.