Withdraw stored analysis if the track sample count changes

[Daniel Schürmann]

This may happen if the track was cut or in case of seek decoding issues (still in 1.12 alpha).
Currently the waveform does not fit to the samples and the sync feature will fail is such a case.

[joe (joseph-chilcott)]

Hi, I am new to the Mixxx project and as thought I would try and tackle this as my first bug. Would I be able to get more information on this bug and how to replicate it? When you refer to stored analysis, is this the pre-view wave form that appears after dragging a track onto one of the decks?

Thanks,
Joe

[Daniel Schürmann (daschuer)]

Thank you for offering you help.

Reproduce:
* play a track in Mixxx
* close Mixxx
* cut some samples from the beginning of the track (using e.g. Audacity)
* Play this track again

What happens:
Beatgrid and waveform have an offset, (still match the old track)

What should happen:
Mixxx should detect this and reanalyze the track.

I think the same will happen if you replace the track with a completely different one.

Todo:
* setup a powerful development environment.
* Analyse why it happens.
* I think we have already some code to detect some of these situation in Library scanner. Check how this can interact with this issue.
* Propose a solution.
* Code it.

This will help to start:
http://www.mixxx.org/wiki/doku.php/bugfix_workflow

And ... Ask, if you get stucked.

[joe (joseph-chilcott)]

Hi Daniel,

Many thanks for the information. Just one thing, when you say 'close Mixxx' do you mean minimise mixxx or exit mixxx? The reason I ask is, mixxx does not seem to retain a previous session once closed. If I do close mixxx and then reload the edited track, the waveform is updated and represents the edited version of the track. Sorry if this is a newbie question :)

[Daniel Schürmann (daschuer)]

I mean: Exit Mixxx.

I have just tested this:
I have started Mixxx, played Two tracks, closed Mixxx, switched the names from the tracks.
After restart. The first track contains the audio from the second track and vice verse. The waveform is not reanalysed.

[Ferran Pujol (ferranpujol)]

Would this work?

1-Store in the database the last time when Mixxx modified a track file.
2-When the track is loaded, compare the database last modified time with the OS last modified time. If Mixxx is not the last app to modify the track, re-analyze it.

[joe (joseph-chilcott)]

Hi Ferran,

Have you been able to replicate this issue, I am still having problems.
When I restart Mixxx, it never remembers what I have cued up on either
deck. Therefore I do not see this problem as I am forced to reload the
track each time. This could be a newbie thing (I have looked through the
mixxx documentation and config but could not see anything that would help.

If you were able to to replicate this issue can you tell me what the Git
commit ID was that you are building against when you see this issue? (
*Daniel- can you tell me the Git commit ID that you are also building
against when you see this issue?)*
I cannot comment in much depth on the solution you have proposed, however
it seems reasonable. Would this solution work if the user loaded a track
in mixxx, minimized Mixxx, edited the track and then maximized Mixxx again?

Many thanks,
Joe

On Thu, Jul 30, 2015 at 7:06 PM, Ferran Pujol <email address hidden>
wrote:

> Would this work?
>
> 1-Store in the database the last time when Mixxx modified a track file.
> 2-When the track is loaded, compare the database last modified time with
> the OS last modified time. If Mixxx is not the last app to modify the
> track, re-analyze it.
>
> --
> You received this bug notification because you are subscribed to the bug
> report.
> https://bugs.launchpad.net/bugs/1457746
>
> Title:
> Withdraw stored analysis if the track sample count changes
>
> Status in Mixxx:
> New
>
> Bug description:
> This may happen if the track was cut or in case of seek decoding issues
> (still in 1.12 alpha).
> Currently the waveform does not fit to the samples and the sync feature
> will fail is such a case.
>
> To manage notifications about this bug go to:
> https://bugs.launchpad.net/mixxx/+bug/1457746/+subscriptions
>

[Swiftb0y (swiftb0y)]

Mixxx now uses GitHub for bug tracking. This bug has been migrated to:
https://github.com/mixxxdj/mixxx/issues/8053