Add support for track selection grooves in Vinyl Control

[daniel lopez]

In traktor on windows, their is a groove on the control vinyl that allows you to select tracks without touching your computer or even using a midi controller. When you try and use the groove in mixxx or xwax, it just plays the song at double speed. I would love to be able to have this functionality in linux at some point, if you need help testing feel free to let me know. -beelzedub

These grooves exist on Serato Scratch Live records and CDs as well. - Sean

[Sean M. Pappalardo (pegasus-renegadetech)]

Mark of xwax explained that the track select grooves are nothing more than a continuation of the same time code as the main groove. There's just a physical separation on the record for reference. This applies to MixVibes, SSL, and Traktor records (but not FinalScratch.) So we would just need to define what absolute time code position begins the track selection area for each vinyl type (or even let the user adjust it,) and when the needle is in that area, signal the TrackSelectKnob CO as appropriate.

[Sean M. Pappalardo (pegasus-renegadetech)]

It might also be interesting to trigger the track load when the needle is placed back into the main timecode area. Either that or when it's left stationary for 3s or so.

[Owen Williams (ywwg)]

This is now implemented in features_xwax2, but has only been tested with Serato vinyl. It uses the "safe" parameter inside xwax to determine where the track control track begins (> safe = track selection). The default xwax values put the safe value at the very end of the record, so those defaults need to be changed.

I tried the 3 second method, but ultimately it works much better to trigger the track load when the needle is moved back to the main timecode area. I also made sure to ignore that selection if the user uses the control track but then manually loads a track with the regular ui.

todo: need to get correct 'safe' values for other vinyl types.

[Swiftb0y (swiftb0y)]

Mixxx now uses GitHub for bug tracking. This bug has been migrated to:
https://github.com/mixxxdj/mixxx/issues/5758