Quantized loops start one beat too early when being exactly on the beat

[Marco Angerer]

When your play position is exactly on the beat and you want to prepare a loop (deck is not playing) with the quantize-option activated, the beginning of the loop will be one beat too early.
This seems to happen at > 50% of all songs.

Steps to reproduce the problem:
1. Activate the quantize-option (magnet)
2. Set a HotCue on any beat
3. Go to this HotCue
4. Start a loop >= 1 -> will start one beat too early

I use Mixxx 1.12.0 alpha on Ubuntu 14.04 with an Intel Core i5

[Owen Williams (ywwg)]

oh yeah, totally annoying.

https://github.com/mixxxdj/mixxx/pull/246

[Marco Angerer (hektikr)]

GOT IT:

replace ll. 146 ff. in beatgrid.cpp with

double beatFraction = (dSamples - firstBeatSample()) / m_dBeatLength;
    double prevBeat = floorf(beatFraction);
    double nextBeat = ceilf(beatFraction);

    // If the position is within 1/100th of the next or previous beat, treat it
    // as if it is that beat.
    const double kEpsilon = .01;

    if (fabs(nextBeat - beatFraction) < kEpsilon) {
     beatFraction = nextBeat;
     //but now we have to update prevBeat
     prevBeat = nextBeat;
    } else if (fabs(prevBeat - beatFraction) < kEpsilon) {
     beatFraction = prevBeat;
     //in this case nextBeat has to be updated
     nextBeat = prevBeat;
    }

[Marco Angerer (hektikr)]

Pull Request:
https://github.com/mixxxdj/mixxx/pull/248

[Owen Williams (ywwg)]

the bug isn't committed until we accept the pr

[Marco Angerer (hektikr)]

I'm new, so: Uups ;)

When do you normally accept pull requests? When Mixxx 1.12 will be released?

[Owen Williams (ywwg)]

One of the other developers will take a look at the pull request and decide if the fix is good. I wouldn't worry about making it in to the next release.

[RJ Skerry-Ryan (rryan)]

This is still present for BeatMaps -- I'll work on it.

[RJ Skerry-Ryan (rryan)]

(I mean I have a fix in progress)

[Owen Williams (ywwg)]

@rryan any progress on the beatmap fix?

[RJ Skerry-Ryan (rryan)]

Yep, fixed in:
https://github.com/mixxxdj/mixxx/commit/a5ac1cd9477700873ae61905b2ac70b036ed6708

[Swiftb0y (swiftb0y)]

Mixxx now uses GitHub for bug tracking. This bug has been migrated to:
https://github.com/mixxxdj/mixxx/issues/7450