The Mini Player shows up when you right-click on an input or output file and choose the Play context menu. It is also possible to play a file by double-clicking on it, or by selecting it and clicking the button. Playback of the file starts immediately.
The Mini Player
The Mini Player is not intended to be a full-featured audio player. In particular:
It will always play through the default audio output device, which is generally a software device that does the mixing between the audio output of different applications.
Playback will fail if the device does not support the audio file's sample rate or number of channels.
Playback will fail if another application has exclusive access to the audio device.
Seeking can be slow with compressed formats (mp3, ogg, etc.), especially on long files.
It can only play files loaded in Quantum or transformed by Quantum.
It does not have any advanced features such as effects, playlists, etc.
If you want to play a file with another player, you can use the Show in the Finder context menu. This will open the file in the
Finderand hightlight it,
so you can then open it with your favorite audio player.
This menu is always available on input files. It is only available on output files once they are fully transformed.
The Mini Player on the other hand can play an output file as soon as its transformation has started, even if it has not finished yet. It will play as much audio as has been already transformed.
In the Mini Player:
The Playback position indicates the relative position of the playback.
The slider indicates the position visually from left (start) to right (end) and the label on the right displays the current playback position in minutes and seconds.
You can drag the knob on the slider to seek through the file.
The Processing position indicates how much of the audio file has already been transformed.
The processing position is updated as the file is being transformed.
The playback is only possible up to the processing position. Once the file is fully transformed, it can be fully played.
The processing position is not shown when playing an input file as the file can always be fully played. Instead, a label with the file duration is shown.
The following shortcut keys are available in the Mini Player:
p: Toggle between playing and paused. Same as the and buttons.
s: Stop playback. Same as the button.
← and → (left and right arrows): Play previous or next file. Same as the and buttons. The up and down arrows can also be used
i: If the file currently being played is an output (transformed) file, plays the corresponding input file.
o (the letter "o"): If the file currently being played is an input file, plays the corresponding output (transformed) file (if there is any).
The i and o keys can be used to quickly toggle between the original file and the transformed file in order to compare them.
Note that the Mini Player window must be selected for these shortcuts to work. The ⌘-p shortcut can be used at any time within the Quantum application to select the Mini Player window.
The ⌘-m shortcut can be used at any time within the Quantum application to select the main window.
The ⌘-i shortcut can be used at any time within the Quantum application to select the information window (if any, see next section) and to cycle between them if many of them are opened.
4.2 The file information dialog
The file information dialog displays various properties of an input or output (transformed) file. To show it, right-click on an input or output file, and choose the Show info... context menu. You can also select an output file and click on the button.
The following figure shows the file information dialog for an output file:
The File Information Dialog for an output file
The dialog has three tabs for an output file (for an input file only the first tab is visible):
Input File: information about the input file. This is the only available tab when opened on an input file. When opened on an output file, this tab gives information about the corresponding input file.
Output File: information about the output (transformed) file.
Transformation: information about the transformation.
Note that the file information dialog only shows information that are relevant for the process of time stretching. This is not a dialog that shows the meta-data (song title, composer, etc.) of the file.
Input File
The following information are shown on the Input File tab:
Name: The name of the file. This is the name of the file on the disk, and not the song name or title. By moving the mouse over the name, the full path on the disk is shown on a tooltip.
Format: The audio file format, including encoding, number of channels and sample rate.
Duration: The duration of the input audio file.
If the file is in a compressed format (mp3, m4a, etc), the displayed value is approximate.
Size: the size of the input file on the disk.
Transformed: the number of times the file was transformed since the application started.
Output File
The following information are shown on the Output File tab:
Name: The name of the file. This is the name of the file on the disk, and not the song name or title. By moving the mouse over the name, the full path on the disk is shown on a tooltip.
Format: The audio file format, including encoding, number of channels and sample rate.
Duration: Various durations, in minutes/seconds and in audio sample frames:
The duration of the corresponding input file.
If the file is in a compressed format (mp3, m4a, etc), the displayed value is an approximation that might drift a little from the exact duration, but usually by less than a second.
Once the file is fully transformed, the value is updated to reflect the exact duration.
The current duration of the output file; this value increases as the file is being transformed.
The expected duration of the output file once it is fully transformed.
The duration of the output file will match this duration once the file is fully transformed.
When quality 1 or 2 is used, the duration of the output file might drift from a few sample frames once fully transformed. Use quality 3 or 4 to make sure the duration of the transformed file is sample-accurate.
When the demo version of Quantum is used, the current duration does not go above 30 seconds of transformed audio.
Size: the size of the output file on the disk.
While the file is being transformed, this is the size of the raw, temporary file, always in 32-bit float raw format.
When the file is fully transformed, this is the size of the file in the specified audio file format (WAVE, AIFF/AIFC or AU, in 16, 24 or 32-bit).
Time stretch ratio: the time stretch ratio as a length ratio (i.e., 2.0 means two times longer (or two times slower) and 0.5 means two times shorter (or two times faster)).
By moving the mouse over the value, the time stretch ratio is also displayed as a length change and as a speed change in a tooltip.
See chapter 3.2.1 for more information on the ways of specifying the time stretching factor.
Quality: the quality settings that was used, between 1 (fastest) and 5 (best quality). See section 3.2.2 for more.
Transient Sensitivity: the value of the transient sensitivity advanced setting used. See section 3.2.2 for more. This value is only displayed if the quality is 3 or more.
Output settings: a summary of the output settings used. See section 3.2.3 for more.
By moving the mouse over the value, the full path of the output directory is shown in a tooltip.
Transformation
The following information are shown on the Transformation tab:
Peak (Input/Output): The peak value of the input file and the peak value of the output file.
These values are computed and updated as the file is being transformed. They only correspond to the true values once the file is fully transformed.
Both values are shown in dB (where 0 dB is the digital maximum) and in parentheses as a digital value (where 1.0 is the digital maximum).
The value for the output file is the value without applying the Prevent clipping setting (see 3.2.3). If the value is above 0 dB and the Prevent clipping setting was enabled, the output file's loudness has been reduced automatically to peak at 0 dB.
Applied gain: The gain that was applied to the output file. It is given by:
The Output gain [dB] setting.
The Prevent clipping options (if it is selected).
See section 3.2.3 for more on these options.
If none of these options was specified, no gain is applied, and "0 dB (1.0)" is shown.
Status: The status of the transformation.
Processing Time: The amount of time spent transforming the file.
If the file is currently being transformed, the ETR (Estimated Time Remaining) is also shown.
Error: This is only shown if there was an error while transforming or saving the file. Possible causes of errors are:
The input file no longer exists (for instance if it has been deleted or moved).
The output file cannot be written because the disk is full, or the output directory is read-only.
4.3 Global Settings
4.3.1 Transform settings
The global transform settings can be changed by choosing the
Quantum, Preferences...
menu, and selecting the "Transform" tab (the first one).
Global Settings: Transformation settings (middle)
There, you can change the default values for the Transform Settings and the Output Settings. These values will be applied to new files.
Only the dialog (1) in the middle of the above figure shows up initially.
Clicking on the button under Default Tranform Settings opens the panel shown on the left (2) to change the default values for the advanced transform settings (discussed in section 3.2.2).
Clicking on the button under Default Output Settings opens the panel shown on the right (3) to change the default values for the output settings (discussed in section 3.2.3).
The values changed here are not applied on the files that are already opened. However, they will be used as the default settings for all files that are subsequently opened (if no input file is selected. Else the settings of the selected input file are reused for subsequent files).
Under Time Stretching Factor (in the main dialog (1)), the Default option allows you to select which time stretching option (length change, speed change, tempo from/to...) is visible by default when adding new files.
Click on to save the specified settings for this session and all future sessions (the next time you start the application)
Click on to use the specified settings for this session only. The values will not be saved for the next time you start the application.
Click on to cancel all changes.
Click on to revert all settings to the factory defaults. Note that the factory defaults are not saved until you hit or .
Note: the above buttons apply to the settings of all the three tabs.
4.3.2 Processing settings
The global processing settings can be changed by choosing the
Quantum, Preferences...
menu, and selecting the "Processing" tab.
Global Settings: Processing settings
The settings on this tab have no effect on audio aspects (quality, timbre, etc.) of the transformed files. There are more "system" settings.
The processing settings are the following:
Temporary Directory: The directory in which temporary files are placed. When an audio file is transformed, it is first written in raw 32-bit format in this directory. Only when the transformation is finished, it is saved to the output directory and deleted from the temporary directory.
By default, the default system temporary directory is used (its full path is shown in a tooltip). If the chosen temporary directory is not the system default one, you can restore it to the system default one with the button.
To change the temporary directory, click on the button.
The temporary directory must be on a disk that has sufficient space for all the audio files that are transformed at the same time. The required space depends on the length, number of channels and sample rate of the file.
Files stored in the temporary directory are in a 32-bit raw format. They are not meant to be opened or played by other applications.
Files stored in the temporary directory are deleted once the transformation is complete.
Processing threads priority: the priority of the processing threads.
Warning: choosing Normal might make the system unresponsive, especially if the Number of processing threads is set to the maximum.
You should keep the default Low setting. Quantum will always use all the available power; this setting just ensures that it does not slow down other applications.
If you feel Quantum is slowed down by other applications too much, try the Below Normal or Normal setting.
Number of processing threads: the maximum number of threads to use when transforming multiple files. This corresponds to the maximum number of files that will be transformed at the same time, and to the number of CPU cores that will be used.
The maximum value is the number of logical CPU cores.
This setting is not visible on a single-core computer.
The default value is half the number of logical CPU cores, or 2 on a dual core system. On most systems this corresponds to the number of physical CPU cores.
On Apple Silicon (M1), this usually corresponds to the number of high-performance cores.
If the number of logical CPU cores is greater than the number of physical CPU cores, setting a value greater than the number of physical cores
(or the number of high-performance cores)
will only barely improve the overall processing speed (at most by about 20%).
Using the maximum value may make the system unresponsive, especially if Processing threads priority is set to Normal.
Prevent system sleeping: when the ☐ While transforming files box is checked, Quantum will prevent the system from sleeping during the time files are being transformed.
This will prevent the system from sleeping, to ensure the processing is not interrupted before it is finished. This will not prevent the screen or harddisk from sleeping.
This will not prevent the system from sleeping when the battery is low, or when you put it to sleep manually or by closing the lid.
Click on to save the specified settings for this session and all future sessions (the next time you start the application)
Click on to use the specified settings for this session only. The values will not be saved for the next time you start the application.
Click on to cancel all changes.
Click on to revert all settings to the factory defaults. Note that the factory defaults are not saved until you hit or .
Note: the above buttons apply to the settings of all the three tabs.
4.3.3 Appearance settings
The global appearance settings can be changed by choosing the
Quantum, Preferences...
menu, and selecting the "Appearance" tab.
Global Settings: changing the application's appearance
Here you can change the appearance (or skin, theme) of the application. Choose the theme from the "Appearance" drop-down. A preview is displayed on the right.
There are light and dark themes, flat and 3D themes, a high-contrast theme and a native theme.
Notes:
You should restart the application after saving the changes; some theme colors are only applied after restart.
When selecting a theme, a small preview is displayed on the right. This preview shows dummy buttons, sliders, texts, etc. You cannot interact with it.
Themes other than the Native one may not fully comply with Apple Human Interface Guidelines.
The Quantum's icon appears a second time in the dock during a few seconds when changing the theme. This is normal and is used to create the preview.
Changing the theme will close the player and any information dialogs. While it is possible to change the theme while files are being transformed, this is not recommended.
Click on to save the specified settings for this session and all future sessions (the next time you start the application)
Click on to use the specified settings for this session only. The values will not be saved for the next time you start the application.
Click on to cancel all changes.
Click on to revert all settings to the factory defaults. Note that the factory defaults are not saved until you hit or .
Note: the above buttons apply to the settings of all the three tabs.
4.4 Command Line Version
Warning: this section is for advanced users only. If you don't know about the command line and shell scripts, you probably do not need this feature.
I'm an advanced user
A command-line version of Quantum is available, and is automatically installed together with the application. It can be included in shell scripts, and can run on headless servers or through ssh. It can do most of the things that the normal (graphical) application does.
The command-line version is named qats and is located in the Contents/CommandLine/Contents/MacOS folder inside of the app's package content. It should not be moved from this location.
To see how to use the command-line version, and all the available options, use qats -h.
Notes:
Unix pipes are not supported. The command-line version can only read and write files.
The command-line version can process multiple files in a single invocation (by specifying all files as arguments). In that case it will use multiple CPU cores like the application.
Multiple input audio files can also be specified by passing an .m3u8 playlist file. In its simplest form, an .m3u8 playlist is just a file containing a list of file paths (absolute or relative to the playlist file), one per line, with UTF-8 encoding for special characters. In that case, the same time-stretching ratio and settings are applied to all files of the playlist.
The Mac App Store version is sandboxed. As such the command-line version can only access files that are in your Music folder or subfolders.
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