Playback of M4A files on Windows through SoundSourceMediaFoundation plugin is broken

[Uwe Klotz]

[master]

The tests for sample accurate seeking of M4A files in SoundSourceProxyTest have been disabled on Windows, because the SoundSourceMediaFoundation plugin fails to perform accurate seek operations.

Furthermore reading of sample data sometimes seems to result in more samples than have actually been requested. This is dangerous, because it might write data outside the bounds of the buffer that is allocated by the caller!

*TODO*
* Determine the exact length of the audio stream in frames/samples and set by invoking setFrameCount(). Currently this is an approximate value calculated from the duration.
* Fix seeking and decoding in SoundSourceMediaFoundation
* Remove #ifndef __WINDOWS__ // TODO(XXX) from soundproxy_test.cpp and re-add ".m4a" to availableFileNameSuffixes
* No more violations of DEBUG_ASSERTs in the caller's code, e.g. AnalyserQueue

[Uwe Klotz (uklotzde-deactivatedaccount)]

I neither have the time to fix this issue nor do I have a native Windows dev. environment (only a slow VM). But I'm happy support anyone who is willing to take responsibility for this task.

For an example on how to do the buffering of decoded sample data in the "leftover" buffer please have a look at SoundSourceFLAC and SoundSourceM4A.

[Uwe Klotz (uklotzde-deactivatedaccount)]

Maked as "Confirmed" since there are many bug reports about the SoundSourceMediaFoundation that is still broken.

[rimorob (boris-1)]

I'm not sure that I'm following what's going on here. If the bug is in a 3rd party plug-in, is that the only plug-in that can decode m4a?

Is there a work-around? What's the best alternative format to convert to, without using a lot more disk space?

[Uwe Klotz (uklotzde-deactivatedaccount)]

Sorry, no workaround. The Mixxx plugin needs to be fixed.

If someone is able to give me instructions for a working Windows development environment I might be able to fix it. But my time is limited ;)

[Daniel Schürmann (daschuer)]

 > What's the best alternative format to convert to, without using a lot more disk space?

Ogg Vobis.
It is somehow similar to m4a in terms of quality vs. files size.
But be aware that the re-encoding always suffer the short comings of both codecs.

To avoid that you may re-encode your file to the lossless FLAC format which unfortunately blows up the file size.

In any case, keep the original m4a files.

[Uwe Klotz (uklotzde-deactivatedaccount)]

https://github.com/mixxxdj/mixxx/pull/1112

[Swiftb0y (swiftb0y)]

Mixxx now uses GitHub for bug tracking. This bug has been migrated to:
https://github.com/mixxxdj/mixxx/issues/8210