Feature-Request: turntablist transcription visualization

We could create a visualization similar to this by drawing the carrier wave (on the time-coded vinyl) on a frequency versus time graph (spectrogram).

The larger issue would be where to actually show the visualization, screen real-estate is precious.

I'm not sure what the vertical axis of the plot is. It's not quite rate, it's not carrier wave, and it's not just timecode.

I can't scratch so I can't really compare a recording of the carrier wave to this. One thing I noticed that's different for sure, is when he cuts the cross-fader in and out it alters the thickness/visibility of the wave, this corresponds to the db on the master, but that posses some really obvious problems.

Those problems are why I think those visuals are really contrived. Notice how there's not a second deck? That's because in order to get just the carrier wave an still get those cross-fader cuts they had to use the master channel. Playing another track would completely distort that output.

The best we can do is get the lines but without the cuts it doesn't really give a good visual representation.

From http://jklabs.net/projects/visualscratch/description.html
"We capture turntable velocity using Ms. Pinky and fader position using an Ecler Nuo 4. The scratching sound is generated in Max/MSP. Then we scale the control data (turntable and fader) to ±1.0, the range of digital audio signals. The control data is saved to one audio file, and scratch audio to another.

With the two sound files as input, the graphics are generated in Processing, using the incredibly helpful Ess, PDF and MovieMaker libraries. The y-axis position reflects the velocity of the turntable, color is based on the frequency content of the scratch audio, and the thickness of the line is based on the volume."

They're actually able to grab the fader position, we have no way of grabbing the position of an external fader in Mixxx, best we could do use the master channel to grab db.

grab the fader position from a midi crossfader.

Getting it to work for those that only have midi crossfaders seems a bit wasteful considering the work required.

Granted, we could do this pretty easily for those who use controllers in general. My point is, the setup shown in the videos wouldn't really work for Mixxx.

it is a laborious task to write down turntablist transcription and most djs don’t do it.
and even if a dj writes it down, its a idealized representation.
because of that it is harder to reproduce or learn complicated scratches.
this would be change if the software dose this task for you.
not only you get an exact representation of the turntablist transcription, you also get visual feedback in realtime.
the usability of this visualization is for educational purposes, for scratch djs to understand the different scratch techniques.
so i think it would be a unique addition and if you can only use a midi fader it would be a good compromise and no waste of work.