CD seek and scratching

[Daniel Schürmann]

If you seek on general purpose CD player, it just skips some rows of data, without changing the pitch. This is a usefull feature for Mixxx to search a certain place on the track while listen to this seek sound. There is no high pitch, that may make it impossible to recognize the desired spot.

Some controller have a dedicated button for it: vinyl / CD seek.
Mixxx fast forward / backward buttons, currently producing such a high pitched sound. We may consider to replace this by the CD seek sound by default.

The same is also valid for low speed. For detecting a beat, you have to scratch over it with a reasonable speed to not hear only subsonic garbage.
CD players will stick here on a single row and repeat it just again, starting at the current seek position.

A CD spins with 3.5 ... to 8 Hz this leads to a nice looping sound of 125 - 286 ms depending if the laser using an inner or an outer row.

[Daniel Schürmann (daschuer)]

Implementation hints:

This can be implemented by introducing a new EngineBufferScaleLoop subclassing EngineBufferScale like in https://github.com/mixxxdj/mixxx/blob/master/src/engine/enginebufferscalelinear.cpp

In this case, the waveforms, runs smoothly over the track while playing a repeated short loop.

[Sean M. Pappalardo (pegasus-renegadetech)]

This feature would be very difficult to use if the waveform moved along with the audio stutter. If this is implemented, only the sound should stutter. The waveform should only move when the jog/mouse drag is moved.

[Daniel Schürmann (daschuer)]

That was what I am trying to say.

[Swiftb0y (swiftb0y)]

Mixxx now uses GitHub for bug tracking. This bug has been migrated to:
https://github.com/mixxxdj/mixxx/issues/9305