These seem to have appeared in gstreamer 1.26,
which is the version we need to use to guard the handling.
These are effectively geometrically located on the same azimuth,
but on the layer above than the non-top (i.e. middle layer)
surround channels. But they are still surround channels,
which ebur128 does not bias loudness-wise.
At least this is my understanding.
This improves the performance of the analysis (by 2x!),
by offloading non-`libebur128`-computations (i.e. decode-convert)
to a separate thread, thus reducing walltime.
The most juicy bit!
This is based on Song Fingerprint Analysis,
but here we must know the actual song, and not just the file.
The library supports only interleaved S16/S32/F32/F64,
so we must be sure we insert `audioconvert` into pipeline.
One point of contention here for me, is whether we should
feed the frames to the library the moment we get them
in `NewBufferCallback`, or collect them in a buffer
and pass them all at once. I've gone with the former,
because it seems like that is not the worst choice:
https://github.com/strawberrymusicplayer/strawberry/pull/1216#issuecomment-1610075876
In principle, the analysis *could* fail,
so we want to handle that gracefully.
