GSoC 2022 Ideas

Student Project Ideas for Google Summer of Code 2022

This page lists the suggested tasks to build a 175 hour (medium sized) or 350 hour (large project) for Google Summer of Code 2022. The ideas are already assigned to a example project, but feel free to use them for building your own project adding your own ideas, to make it suit perfectly to you, your skills and your time line.

If you are interested in applying to GSoC, read GSoC Advice before applying or getting involved. Only students that are active members of the Mixxx community are accepted. If this is not the case yet, just say hello at https://mixxx.zulipchat.com and discuss your Ideas and use cases with us.

Spin-Up/Spin-Down effect

Some Controller mappings have implemented a Spin-Up/Spin-Down to mimic the inertia of a turn table. This should be moved into the engine, so that it is accessible without a controller.

Part of the project is to record the spin up of a real turn table to get to know of the real acceleration curve and model this via software. You may also deal with the BPM sync feature, in a way that the spin up and down integrates faultlessly into a mix.

https://bugs.launchpad.net/mixxx/+bug/1692261

• Expected Outcome: A flawlessly working spin up and down effect accessible without controller
• Skills: Good understanding of sound processing, C++
• Possible Mentor: Owen Williams
• Difficulty: Medium
• Size: 350 h

Scratch smoothing.

Our scratching algorithm suffers from jitter noise created by the latency of the midi messages. It also suffers from a so called sticker drift, an incrementing offset shifting away form the original scratch sample. Part of this project is to filter the discrete messages from the controller in a way that you can either "play" the track without much wobbling by turning the jog wheel, and keep the position during scratching.

We may also make use of the time stamps of the midi messages. https://bugs.launchpad.net/mixxx/+bug/1157573

The required controller can be provided as a loan.

• Expected Outcome: Wobble fee scratching using a joggwheel
• Skills: Good understanding of real time processing, C++
• Possible Mentor: Daniel Schürmann s
• Difficulty: Hard
• Size: 350 h

Sharp Scratching

Currently crossfader changes are stretched on audio buffer time to avoid pop sounds. This is too long for some scratching styles. During this project you need to dive into the audio engine code find the code that is responsible for crossfading and make it independent from the audio buffer size.

https://bugs.launchpad.net/mixxx/+bug/1703475

• Expected Outcome: Cut type Crossfader curve, suitable for scratching.
• Skills: Good understanding of sound processing, C++
• Possible Mentor: Daniel Schürmann
• Difficulty: Medium
• Size: 175 h

Resample options

Mixxx uses a linear resample when scratching. This is blazing fast, but the sound can be improved. Here Mixxx should provide more resample options. https://bugs.launchpad.net/mixxx/+bug/1775164

Graceful recovery of controllers

If a controller is accidentally unplugged it has to be manually reconfigured, which is a party stopper. Mixxx should do it automatically. This project has two stages, fist behave like a real DJ: fix the issue but faster. So the the time of silence on the dance floor is kept short. The advance stage of this project is to implement real Hot Plug And Play. In order to that you likely need to touch the low level inside third party libraries.

Graceful suspend/resume support:

Mixxx should be able to continue playing after cumming back from the suspend state of the PC. https://bugs.launchpad.net/mixxx/+bug/1744641

Auto Updater for Windows and MacOs

Mixxx should look up our download page and automatically update itself in case an update is available.

Track suggestion feature

Mixxx shall suggest compatible tracks matching the current playing one. The feature may use existing meta data like bpm genre and key or tab online resources like LastFM and similar. https://bugs.launchpad.net/mixxx/+bug/889898

Transpose / Pitch shift effect

There should be an independent effect for pitch shifting. In addition to our main pitch shift feature this should be implemented as an independent effect with a wider range of parameter values. https://bugs.launchpad.net/mixxx/+bug/1299035

Something Else!

As always with Summer of Code, you aren't limited to the suggestions we've made here. If you've got a great idea for a project involving Mixxx then we're looking forward to hearing about it. We recommend spending more than a few days using Mixxx and participating in the community to develop a better understanding of areas where Mixxx could use improvement. Our bug tracker is full of wishlist bugs and other ideas scattered throughout, so if you browse through it, you may find many more ideas for GSoC projects.

IMPORTANT: You should contact us first to get feedback if you're going to submit a proposal for your own project idea! We very rarely approve ideas students propose. If you're not already experienced with DJ equipment, we recommend sticking with one of the ideas above.