pyTardis

A demo Python project using PySimpleGUI, PIL and VLC

Background

Some time ago, as an Arduino and 3D printing hobbyist, I created a model of the Doctor Who TARDIS ¹ with flashing LEDs and a speaker playing short clips from the show. Some day I expect to make a GitHub project detailing how I made it, but in the meantime you can see a video of it in operation on YouTube.

In order to further my understanding of Python in general, and to possibly create a "prototyping" mechanism for further updates to the Arduino code, I created this project. This involved using several packages to:

• Display a GUI (PySimpleGUI)
• Create and display animated images (Pillow)
• Play sounds (python-vlc) [requires VLC app be installed]
• package it all up for publication (GitHub, MarkDown)

I had already written several utilities for myself with minimal UIs using PySimpleGUI (and this application isn't that complicated, either) so I stayed with that package for the UI.

I was having difficulty creating and using animated GIFs for the UI, so I dug into Pillow for file creation and display. The end result was not 100% satisfactory: both Pillow and tkinter (which PySimpleGUI relies upon) have a history of issues with transparent GIFs, so I went the "animated PNG" (APNG) route. The AnimatedImage class included here was created to access the individual frame durations available in both GIF and APNG for slightly more nuanced animations, to handle "loop" counts > 0, and to optionally use the "default image" specified for APNG (which I implemented with duration=0 initial frames) for items like GUI image buttons that are static until clicked. I originally tried to simply hook into the PySimpleGUI.Image members via a subclass that overrode Image.update_animation(), but then went completely separate from it in case the implementation changes.

For the audio, I investigated numerous Python sound packages. Many offered limited sound file format support (.wav only), blocked the GUI while playing, or couldn't interrupt a song while playing. The first workable package I used was PyObjC and AppKit.NSSound for macOS which supports a callback when a track has finished, but of course this isn't cross-platform. I ended up using the python-vlc package since I already had the VLC player installed on my machine, and implemented the "playback complete" callback it provides.

Operation

The application is very straight-forward. The buttons will: switch to the previous track, play the curren track (or stop the current track if it is already playing), go to the next track, or exit the program. The track list may be clicked on to select a specific clip.

The volume may be changed with the slider². Note this is moderated by your machine's sound system settings: full volume is just your normal desktop level; all lower values are quieter than normal.

Clicking on "Demo Mode" will cause the tracks to play continuously in succession.

The code

This code requires the Python packages listed in the requirements.txt file. It also requires that the VLC Media Player application be installed on your machine.

• tardis.py - the "main" script with the PySimpleGUI event loop; drives the whole app.
• tracks.py - "data" file that lists the sound clips and their associated animations.
• tardis_controller.py - called from the GUI to control audio and animations from the tracks list.
• video_player.py - animates the TARDIS, which is actually 2 PySimpleGUI.Image elements (the beacon and the TARDIS body windows) based on the tracks settings. I could have split his into 3 parts (beacon, windows and static body), but I was getting RSI re-editing images in my photo editor.
• animated_image.py - updates PySimpleGUI.Image elements to display the animation frames.
• audio_player.py - uses the VLC player to play the tracks-specified sound files.
• timed_print.py - utility class that can be used to prefix print output with "ss:mmm".
• images/* - contains all the static and animated images used (and some unused ones, too).
• audio/* - contains all the sound files played.

I spent ("wasted") a lot of time learning how to edit images to replicate the LED animations in my model, as well as creating several styles of media control buttons. The final result was simply shrinking/expanding button images from the PySimpleGUI demos. The results, as well as a number of hacky scripts to "auto-generate" some files, are not included in the repository. References to an "./imagery" folder in test secitons of code may still be present.

Credits

Beside the afore-mentioned Python packages, I made of use:

• subpng.com/png-24lvw3 - app icon
• subpng.com/png-6zn8ai - full TARDIS image
• subpng.com/png-fv1r47 - weeping angel (blink and you'll miss it)
• acegif.com/wp-content/gifs/fire-102.gif - flames animation
• PySimpleGUI ButtonGraphics - control buttons

Don't Blink

Footnotes

1. Sydney Newman (Creator). (1963-1989, 2005-present) Doctor Who [Television series]. BBC. ↩

2. "These go to eleven" - Reiner, R. (Director). (1984). This is Spinal Tap [Film]. Goldcrest Films International. ↩