cklicking on the woverwiew for a now position produces audible pops

[Daniel Schürmann]

When I click on the Woverwiew. To jump to a new position while the track is playing I can sometimes hear a pop.
The cursor seems to jump to a random position before it final jumps to the click position.
It hears like the audio output does the same.

[RJ Skerry-Ryan (rryan)]

I put a printline in EngineBuffer::slotControlSeek and I only see one seek per click on WOverview.

Is it a full engine under-run? I.e. do you hear other tracks skip as well as the seeking track? If so then the most likely explanation is that the seek blocked the callback by locking m_engineLock in setNewPlaypos. This is fixed in the engine-control-refactor branch which prevents any thread other than the engine thread from touching EngineBuffer and gets rid of these locks.

[Daniel Schürmann (daschuer)]

After some investigations, things are getting clear.
This issue are mainly two:

* Jumping cursor: It is caused by a play position update which might be delayed on a queue from before the seek.
* The pops my caused by a race condition between EngineBuffer::setNewPlaypos and EngineBuffer::process.
The are called from different threads but are both using non thread save EnginebufferScale.

Unfortunately I have no test for to proof the last one.

The attached patch is more a hack to check it out. It is on Top of Bug #1094149 patch.
But I can still hear pops with the wav from test folder.

[RJ Skerry-Ryan (rryan)]

we now crossfade

[Swiftb0y (swiftb0y)]

Mixxx now uses GitHub for bug tracking. This bug has been migrated to:
https://github.com/mixxxdj/mixxx/issues/6794