SlowPlay

SlowPlay is a simple audio player with speed/pitch change capabilities, based on GStreamer. It is meant to help music students/teachers transcribe music and play along with it.

Made by a musician for musicians

Inspiration

This software is heavily inspired, although not forked, by Play It Slowly by Jonas Wagner.

I've been using Play It Slowly as my music classes companion for ages, but unfortunately it is no longer mantained and I started experiencing problems since I've updated my laptop OS, so I decided to rewrite it.

Thank you Jonas for your work.

Features

• Speed and pitch change on the fly
• YouTube audio extraction from URL
• Loop a range of the song, with fine adjustment of boundaries
• Modified audio export in MP3 or WAV audio format
• No nonsense keyboard shortcuts
• ...and more!

Speed and pitch change:

SlowPlay can speed down/up songs or change their pitch independently "on the fly". You can import all the most common audio files format (mp3, wav, flac, aif...).

Speed change is made by moving the slider which will change it in 5% steps, or by entering the precise percentage value in the edit box (eg 87%).You can transpose your song up and down by semitones or fine adjust the pitch by cents, in case the song is not in tune with your instruments. For your convenience, SlowPlay offers several numeric keypad shortcuts. Please take a look at the shortcut list further on in this document.

YouTube audio extraction:

SlowPlay can extract audio from YouTube videos and treat it like a regular audio file. Please follow these steps to operate on YouTube videos:

• Click on the YouTube button to open the YouTube dialog
• Paste a valid YouTube URL in the upper box and click on the YouTube icon next to it
• The dialog will search for the specified URL and show the video info and its thumbnail
• If that's the video you are looking for, click on "Open" button on the dialog to import it and get back to the main window (downloading and extracting audio can take a little time, meanwhile the app might be unresponsive. Please wait until done)

Audio extracted from YouTube are marked with a leading "(YT)" on the title.

Note To enable this feature, you need install the latest version of yt-dlp and ffmpeg. Make sure yt-dlp it is present on your execution path. If yt-dlp is not found on your system, you will get an error.

Loop A/B:

This function allows you to loop playback a section of the song. Click on the "Loop control" tab to access all the loop related controls.

Use the "Set loop start" (shortcut "A" or num keypad divide) and "Set loop end" (shortcut "B" or num keypad multiply) buttons while playing to mark the loop boundaries. Toggle the "Enable loop" switch (shortcut "L") to engage/disengage loop playing. You can reset the A/B point using the reset buttons or pressing "Ctrl+A" and "Ctrl+B" on your keyboard.

To achieve maximum execution precision, you can fine adjust the loop points by moving them left and right by 10 or 100 milliseconds using the associated buttons. NOTE: Please keep in mind that there can be very short silence gap when restarting the loop. This is normal and it can't be avoided

Export modified audio:

It is possible to export modified songs by using the "Save as..." button. You can save your files either in mp3 or wav format, based on the extension of file to be saved. Currently saved audio files are in the format of 44.1K 16bit stereo. Mp3 are saved as constant bitrate 192k. Volume setting and metadata are ignored in the export operation.

Optimized keyobard shortcuts:

If you use SlowPlay for music practicing, you probably want access its functions without using the mouse or both hands, which is why most important shortcuts are assigned to the numeric keypads.

• Numbers in the left column (1, 4, 7) move the song position back by 5, 10 and 15 seconds. Numbers on the right column (3, 6, 9) move it forward accordingly. You can reach the song position you want to reharse in a bit.

• Speed controls are assigned to the central column. Numbers 2 and 8 change speed by -5% and +5% respectively, while number 5 resets the speed to normal.

• Plus and minus keys transpose the song by semitones

• Loop start and loop end can be set using the Divide and the Multiply keys respectively

• Number 0 start and pause the playback while the Dot stop and rewind.

I highly recommend taking some time to familiarize yourself with these keyboard shortucts, as they will save you a lot of time in the long run! Personally, I've been using this key combination for my music classes for a while now, and I can't think of anything better.

See the shortcuts section for a more complete key reference.

Other features:

• Recent files list: To access the recent files list use the Ctrl+R shortcut, or right-click on the "Open" button. SlowPlay keeps track of the last 16 played files and all the playback parameters (speed, pitch, cents and volume), which are restored as you load the song again. If the software is launched without specifying any media in the command line, it attempts to reopen the last played track. If the last played song was extracted from a YouTube video, the app will not automatically open it to prevent unwanted downloads. You can dwonload it again by accessing the recent files dialog.

• Drag-n-drop: you can drop audio files straight from your file manager or from other applications.

• gstreamer audio sink: you can specify a different gstreamer sink for particular needs by supplying the --sink option from the command line. Example: the following command will send output to JACK audio slowplay --sink jackaudiosink

Installation

There are a couple of options to install SlowPlay depending upon your Linux distribution.

NOTE: currently SlowPlay is only available for the Linux operating system.

Debian derivative distributions (Debian, Ubuntu, Mint etc...)

Please download the slowplay[version-num].deb from this repository latest release and install it with your package manager.

You can also install it from the command line. Here's an example, assuming you have downloaded the .DEB file into your home folder:

dpkg -i ~/slowplay[version-num].deb

Other distributions

For other distributions, you can manually install the app. Here are the steps to follow:

• Download the compressed file slowplay[version-num].tar.gz from the latest release.
• Extract it on a folder present your system path (tipically /opt or ~/.local/bin)
• Run the executable file slowplay

Optionally, you can integrate SlowPlay into you desktop environment using a menu editor or by creating a .desktop file into ~/.local/share/applications. The detailed procedure on how to integrate the app into your DE is beyond the scope of this manual. Please refer to your distro documentation.

Shortcuts

SlowPlay offers the following shortcuts:

General operations:

• Ctrl+O: Open a file
• Ctrl+R: Open recent files list
• Ctrl+Y: Open YouTube search dialog
• Ctrl+Q: Quit application

Playback controls:

The following commands are all assigned to the numeric keypad. Refer to the drawing below for visual help.

• 0 or spacebar: Toggle Play/Pause

• . (numeric pad dot): Stop and Rewind

• HOME: Rewind to the start of song, or to the start of loop when engaged

• 1 or left arrow: Rewind 5 seconds

• 4: Rewind 10 seconds

• 7: Rewind 15 seconds

• 3 or right arrow: Forward 5 seconds

• 6: Forward 10 seconds

• 9: Forward 15 seconds

• 8: Increase speed by 5%

• 2: Decrease speed by 5%

• 5: Reset speed to 100%

• +: Transpose +1 semitone

• -: Transpose -1 semitone

Loop controls:

• L: Toggle loop playing

• A or Keypad Divide: Sets the start loop point to the current playing position

• Ctrl+A: Resets the start loop point to the start of the song

• B or Keypad Multiply: Sets the end loop point to the current playing position

• Ctrl+B: Resets the end loop point to the end of the song

(please make sure none of the input boxes have the focus. Click on an empty area of the app to take the focus back from an input box)