Album count differences in 6.5.1

[the_bertrum]

Hello all,

I'm not posting this in the bug thread because it doesn't seem to be an actual bug, just a difference that I'd like to get explained.  I have 6.5.1 installed on one of my devices and 6.4.2 on another.  Both use the same NAS file system to store the music and yet 6.5.1 reports one less album in the "View Status Done: nnn albums processed" message on the Library Status screen.  I've done a side by side comparison and the libraries have exactly the same albums in them and there are no errors in the log of the MPD scan so I guess 6.4.2 counts something that 6.5.0 does not.  I'd lay a small wager on it being the "Stereo Test".  As I say this clearly isn't a bug, all the music I expect to see is there but it would be nice to understand what the reason is.

6.5.0 is pretty cool though, just a small amount of muscle memory I need to retrain for tasks that are subtly different, but compared to the changes wrought on new releases of other interfaces, this is small beer and mostly more useful.

[Tim Curtis]

That particular status is referring to the number of album directories scanned by the thumbnail image generator. In 6.4.2 and prior versions we were getting the input directory list from MPD but we had to wait until MPD database update finished. In the 6.5.x series we get the directory listing from Linux which allow us to run thumbnail generation and MPD update in parallel.

I see same diff in counts on my end. mpc stats reports N albums and the thumbnail generator status reports N + 1.

I'll investigate.

[Tim Curtis]

In my particular case I think whats happening is that the command mpc stats is reporting the number of unique Album tags. The thumbnail generator reports the number of unique album paths.

I happen to have two different albums whose Album tags = "Greatest Hits". Each album is counted by the thumbnail generator.
/mnt/NAS/FLAC/Artist1/Greatist Hits
/mnt/NAS/FLAC/Artist2/Greatist Hits

The output from MPD is below and shows only one occurrence of Greatest Hits

mpc list album | grep -w "^Greatest Hits"
Greatest Hits

-Tim

[TheOldPresbyope]

This an off-by-one situation can also occur if one or more tracks does not have an entry in the Album field in its metadata tag. Somewhat schizophrenically, MPD doesn't count it as an album but it remembers the null name.

Here's a simple test of 6.5.1 with three directories on the SDCARD, each containing one track. Two of the tracks have an entry in the Album field. The third, Northern Exposure, does not. (These were left over from our testing the seekbar issue.)

Code:

pi@moodeCD:/mnt/SDCARD $ ls -R
.:
'Big Science'  'Northern Exposure'  'Stereo Test'

'./Big Science':
longflac.flac

'./Northern Exposure':
'Northern Exposure (North) (DJ Mix).flac'

'./Stereo Test':
LRMonoPhase4.flac

When I regenerate the album cover thumbnail cache and view the status, it reports "3 albums processed". OTOH, MPD says

Code:

pi@moodeCD:/mnt/SDCARD/Stereo Test $ mpc stats
Artists:      4
Albums:       2
Songs:        3

Play Time:    0 days, 2:36:11
Uptime:       1 days, 19:16:34
DB Updated:   Tue Apr 28 08:06:21 2020
DB Play Time: 0 days, 2:36:49

pi@moodeCD:/mnt/SDCARD/Stereo Test $ mpc list album

Big Science
Stereo Test

See that first blank line under 'mpc list album'? That's the null album name, so in a sense MPD does know there's a third album.

So, without reviewing the code change between 6.4.2 and 6.5.1, I'd guess 6.4.2 would report 2 albums processed for this test case.

Regards,
Kent

PS - @the_bertrum. I would have seen your bet   As can inferred from the above, 'Stereo test' is an album because the single track has the value 'Stereo Test' in the Album field of its metadata tag.

[Tim Curtis]

We get same results. Mpc stats is not reporting the correct album count :-0

[the_bertrum]

Thanks for looking chaps, my mind is at rest. Frankly the album count can be out by however much it wants as long as all the music is there and playable

@TheOldPresbyope I'll make good on my bet by throwing some more cash in the Moode donation pot.