Fall back on AnalyserBPM if AnalyserBeats fails to load VAMP plugin

[RJ Skerry-Ryan]

Now that beat detection can possibly fail due to plugin issues we have to fall back on AnalyserBPM if the VAMP plugin is not present. This will be required for the app-store at least since we may not provide the QM plugin with the app store.

[Sean M. Pappalardo (pegasus-renegadetech)]

The only problem with this is that we'll still be getting complaints about how the BPM detection sucks. Some will have great experiences, others not so. This means we still need to try to improve AnalyzerBPM.

[Max Linke (max-linke)]

This patch checks if the vamp-plugin can be loaded. Falls back to AnalyserBPM if this is not the case

[Daniel Schürmann (daschuer)]

Hi Max,

thank you for the patch. It looks good to me.
Please add a debug message that is falls back to old analyzer when it is the case.

Further we should reflect this state in the preference GUI.
I think currently all settings are grayed out, but some are needed for the old analyzer as well.

Kind regards
Daniel

[Max Linke (max-linke)]

thanks for your comments.

I've seen that we have completely other preferences for the old analyser(dlgPrefBpm) and the vamp-plugin(DlgPrefBeats).
Which one is loaded depends on preprocessor directives. Should I load the old one in case the vamp-plugin could not be loaded?

What is the best way to inform the user that the plugin can't be loaded. Just a warning message each time mixxx is started or also a warning in the BPMDetection preferences?

[RJ Skerry-Ryan (rryan)]

Hm, good point about the dialog. I think for consistency we should keep the new-style dialog and delete the old dialog. We should make the legacy analyser an option in the algorithm dropdown box.

[Max Linke (max-linke)]

should the dialog then show different options depending on the choosen analyser? So that we kind of combine the old and new dialog?

[RJ Skerry-Ryan (rryan)]

I think we should keep only the new dialog and just grey out the constant and offset detection box. The other options (re-analyse, fast-detection, min/max bpm).

Now that I think about it, this is from before we had much experience with VAMP and I was worried we would have plugin loading issues. Now that we've had very few reports of this I think the main driver here is the case where we can't provide the QM plugin. If you look at the plugin definition in vamp-plugins/libmain.cpp, the old analyser is already built into the plugin and you can just uncomment the line to define it in the plugin manifest.

Maybe this bug is unnecessary and we should really just be figuring out how to represent whether offset-detection and fixed-tempo features are available with your selected plugin.

[Max Linke (max-linke)]

I commented out the three lines in libmain.cpp. Mixxx then crashes with the following message

./mixxx: symbol lookup error: /home/kain88/Documents/FOSS/Mixxx-Dev/beta/1.11/mixxx/lin64_build/vamp-plugins/libmixxxminimal.so: undefined symbol: _ZN17MixxxBpmDetectionC1Ef

[Max Linke (max-linke)]

I activated the soundtouch bpm detection.

With this patch the soundtouch analyser is shown if qm is not found. The problem ist that when I tried to analyse
a song with the st-analyser mixxx crashes

./mixxx: symbol lookup error: /home/kain88/Documents/FOSS/Mixxx-Dev/beta/1.11/mixxx/lin64_build/vamp-plugins/libmixxxminimal.so: undefined symbol: _ZN10soundtouch9BPMDetectC1Eii

I guess that there is an error in building libmixxxminimal.so but I can't find it in the SConscript

[Max Linke (max-linke)]

I just found that in mixxxbpmdetection.cpp we do ' #include "BPMDetect.h" '. I can't find that file I think that is the reason for the lookup error

the problem is in line
http://bazaar.launchpad.net/~mixxxdevelopers/mixxx/release-1.11.x/view/head:/mixxx/vamp-plugins/plugins/MixxxBpmDetection.cpp#L205

[Max Linke (max-linke)]

This patch will use QM as default but will fallback to ST in case it is not found. All this happens in dlgprefbeats.
thanks to rryan's help scons now builds libmixxxminimal correct with ST.

I can also grayout some options if this is wanted but from what I can see they are all specific to both analysers or just to analyserbeats.*

[Max Linke (max-linke)]

this patch would remove the old analyser completely(hope I found it all) from mixxx and only leave the port in vamp-plugins.

[Max Linke (max-linke)]

also grays out constant and offset detection box.

[RJ Skerry-Ryan (rryan)]

Great! Looks good, please commit.

[Swiftb0y (swiftb0y)]

Mixxx now uses GitHub for bug tracking. This bug has been migrated to:
https://github.com/mixxxdj/mixxx/issues/6440