[SOLVED] Incomplete ArtWork Scan

[Tim Curtis]

Now open Library Config, regenerate the Thumbnail cache and look in the Moode log again for the stats and any errors.

[Nautilus]

Now open Library Config, regenerate the Thumbnail cache and look in the Moode log again for the stats and any errors.

Hi Tim,

  I have done dozen of times, as well as "Library Update", "Refresh" and "Reboots", but here it is:

The programs included with moOde are free software; the
exact distribution terms for each program are described
in the individual files in /usr/share/doc/*/copyright.
Moode comes with absolutely no warranties expressed or
implied, or any other guarantees.

pi@moode:~ $ moodeutl -l
20210602 222108 worker: -- Start
20210602 222108 worker: Successfully daemonized
20210602 222108 worker: Integrity check (passed)
20210602 222108 worker: File check (OK)
20210602 222109 worker: Session vacuumed
20210602 222109 worker: Session loaded
20210602 222109 worker: Debug logging (OFF)
20210602 222109 worker: -- Audio debug
20210602 222109 worker: ALSA cards: (0:b1 | 1:Headphones | 2:G20 | 3:empty
20210602 222109 worker: MPD config: (2:Gustard USB Audio 2.0 | mixerPCM) | card:2)
20210602 222109 worker: ALSA mixer actual (PCM)
20210602 222109 worker: ALSA PCM volume set to (amixer: Unable to find simple control 'PCM',0)
20210602 222109 worker: -- System
20210602 222110 worker: Host     (moode)
20210602 222110 worker: moOde    (7.2.1 2021-05-06)
20210602 222110 worker: RaspiOS  (10.6)
20210602 222110 worker: Kernel   (5.4.77-v8+ #1371)
20210602 222110 worker: Platform (Pi-4B 1.4 8GB)
20210602 222110 worker: ARM arch (aarch64, 64-bit kernel)
20210602 222110 worker: MPD ver  (0.22.6_p0x3)
20210602 222110 worker: CPU gov  (ondemand)
20210602 222110 worker: USB boot not available
20210602 222110 worker: File system not expanded yet
20210602 222110 worker: HDMI port off
20210602 222110 worker: -- Network
20210602 222110 worker: eth0 exists
20210602 222110 worker: eth0 wait 0 for IP address
20210602 222113 worker: eth0 wait 1 for IP address
20210602 222116 worker: eth0 wait 2 for IP address
20210602 222119 worker: eth0 wait 3 for IP address
20210602 222122 worker: eth0 wait 4 for IP address
20210603 064634 worker: eth0 address not assigned
20210603 064634 worker: wlan0 exists
20210603 064634 worker: wifi country (US)
20210603 064634 worker: wlan0 trying SSID (El Sótano)
20210603 064634 worker: IP addr (192.168.86.144)
20210603 064634 worker: Netmask (255.255.255.0)
20210603 064634 worker: Gateway (192.168.86.1)
20210603 064634 worker: Pri DNS (192.168.86.1)
20210603 064634 worker: Domain  (lan)
20210603 064634 worker: Pi integrated wlan0 power save disabled
20210603 064634 worker: -- Audio config
20210603 064634 worker: ALSA card number (2)
20210603 064634 worker: MPD audio output (Gustard USB Audio 2.0)
20210603 064634 worker: Audio formats (S32_LE, SPECIAL, DSD_U32_BE)
20210603 064635 worker: ALSA mixer name (PCM)
20210603 064635 worker: MPD volume control (none)
20210603 064635 worker: Hdwr volume controller not detected
20210603 064635 worker: ALSA loopback (Off)
20210603 064635 worker: Reset renderer active flags
20210603 064635 worker: CamillaDSP (off)
20210603 064635 worker: -- MPD startup
20210603 064635 worker: MPD started
20210603 064635 worker: MPD accepting connections
20210603 064635 worker: MPD output 1 ALSA Default (on)
20210603 064635 worker: MPD output 2 ALSA Bluetooth (off)
20210603 064635 worker: MPD output 3 HTTP Server (off)
20210603 064635 worker: MPD crossfade (off)
20210603 064635 worker: MPD ignore CUE files (yes)
20210603 064635 worker: -- Feature availability
20210603 064635 worker: Source select (available)
20210603 064635 worker: Source select (source: MPD)
20210603 064635 worker: Source select (output: Gustard USB Audio 2.0)
20210603 064635 worker: Bluetooth (available)
20210603 064635 worker: Airplay renderer (available)
20210603 064635 worker: Spotify renderer (available)
20210603 064635 worker: Squeezelite (available)
20210603 064635 worker: RoonBridge renderer (not installed)
20210603 064635 worker: UPnP renderer (available)
20210603 064635 worker: DLNA server (available)
20210603 064635 worker: UPnP browser (available)
20210603 064635 worker: GPIO button handler (available)
20210603 064635 worker: Stream recorder (n/a)
20210603 064635 worker: -- Music sources
20210603 064635 worker: USB source (Discoteca)
20210603 064635 worker: NAS and UPnP sources (none configured)
20210603 064635 worker: -- Other
20210603 064635 worker: USB volume knob (Off)
20210603 064635 worker: USB auto-mounter (udisks-glue)
20210603 064635 worker: LED0 (On)
20210603 064635 worker: LED1 (On)
20210603 064635 worker: Saved MPD vol level (0)
20210603 064635 worker: Preamp volume level (0)
20210603 064635 worker: MPD volume level (0) restored
20210603 064635 worker: ALSA volume level (None)
20210603 064635 worker: Auto-play (Off)
20210603 064635 worker: Maintenance interval (3 hours)
20210603 064635 worker: Screen saver activation (Never)
20210603 064635 worker: Session permissions (OK)
20210603 064635 worker: Watchdog started
20210603 064635 worker: Ready
20210603 071509 worker: Job shellinabox
20210603 095915 worker: Job regen_thmcache
20210603 095915 thmcache: Start
20210603 095915 thmcache: Priority: Embedded cover
20210603 095915 thmcache: Res,Qual: Auto
20210603 095915 thmcache: Px ratio: 2
20210603 095915 thmcache: Th width: 200
20210603 095915 thmcache: Thm qual: 75
20210603 095915 thmcache: Scanning: NAS, SDCARD, UPNP, Discoteca
20210603 095956 thmcache: mp3: /var/lib/mpd/music/USB/Discoteca/Foo Fighters/One by One/11 Come Back.mp3
20210603 095956 thmcache: mp3: Zend media exception: File does not contain ID3v2 tag
20210603 100001 thmcache: mp3: /var/lib/mpd/music/USB/Discoteca/Guillemots/Euro Express - 634U/03 Made Up Love Song #43.mp3
20210603 100001 thmcache: mp3: Zend media exception: File does not contain ID3v2 tag of supported version: v2.2
20210603 100001 thmcache: mp3: /var/lib/mpd/music/USB/Discoteca/Guillemots/Trains To Brazil/01 Trains To Brazil.mp3
20210603 100001 thmcache: mp3: Zend media exception: File does not contain ID3v2 tag of supported version: v2.2
20210603 100006 thmcache: mp3: /var/lib/mpd/music/USB/Discoteca/Jason Mraz/Levi's Pioneer Sessions 2010 Revival Recordings/Levis_JasonMraz_SpiritInTheSky.mp3
20210603 100006 thmcache: mp3: Zend media exception: File does not contain ID3v2 tag of supported version: v2.2
20210603 100008 thmcache: mp3: /var/lib/mpd/music/USB/Discoteca/Jethro Tull/Collection/13 Living in the Past.mp3
20210603 100008 thmcache: mp3: Zend media exception: File does not contain ID3v2 tag
pi@moode:~ $

and BTW, under Library > Thumbnail Generator > View Status, I got the same message as at my first post:

Scanning folder 468 USB/Discoteca/LCD Soundsystem/This Is Happening

and that is the first album that stops getting the artwork shown

[TheOldPresbyope]

@Nautilus

I see you have changed from the default 32-bit kernel to what is for us still an experimental 64-bit kernel. I strongly suggest you revert to the default 32-bit kernel until everything is working to your satisfaction. 

As for those Zend errors

Code:

thmcache: mp3: Zend media exception: File does not contain ID3v2 tag of supported version: v2.2

they are relatively harmless in the grand scheme of things but you'll have a more satisfactory use of moOde Library Tag and Album views if you check the tracks using a tool like Mp3tag or similar (you can do a web search on music tagging) and correct any metadata issues.

You haven't said how you associate cover art with albums. Is cover art embedded as metadata in each track? Is a cover art file included in each album directory?

If "USB/Discoteca/LCD Soundsystem/This Is Happening" is "the first album that stops getting the artwork shown" then you could use one of the following commands to explore the associated file system directory, either the longform

Code:

ls "/var/lib/mpd/music/USB/Discoteca/LCD Soundsystem/This Is Happening"

or the shortcut

Code:

ls "/media/Discoteca/LCD Soundsystem/This Is Happening"

[note that in Linux one needs to use balanced single or double quotes to protect space characters when working from the command shell. Instead, one can escape each space character with a backslash but that gets tedious.]

The output of the command should be a listing of files, pesky dotted files, and subdirectories with permissions, sizes, etc. Post it here.

For example, here's an album (from a street performer I stopped and listened to; he gave me 30 minutes of his time in music and discussion, I bought his self-published CD) in one of my test directories

Code:

pi@moode:~ $ ls -laR "/media/MUSIC/FOLK/Brian the Folksinger-A Hobos Dulcimer"
'/media/MUSIC/FOLK/Brian the Folksinger-A Hobos Dulcimer':
total 214496
drwxr-xr-x 2 root root    32768 Sep  1  2019  .
drwxr-xr-x 5 root root    32768 Aug  4  2020  ..
-rw-r--r-- 1 root root 16129115 Sep  1  2019 '01.A Hobos Dulcimer.flac'
-rw-r--r-- 1 root root 20804658 Sep  1  2019 '02.A Satisfied Mind.flac'
-rw-r--r-- 1 root root 11546441 Sep  1  2019 '03.Pack Up Your Sorrows.flac'
-rw-r--r-- 1 root root 15740724 Sep  1  2019 '04.Twinkle, Twinkle Little Star.flac'
-rw-r--r-- 1 root root 17738482 Sep  1  2019 '05.Rich Mans Woman Blues.flac'
-rw-r--r-- 1 root root 25762063 Sep  1  2019 '06.Four Strong Winds.flac'
-rw-r--r-- 1 root root 20661346 Sep  1  2019  07.Evangelina.flac
-rw-r--r-- 1 root root 14418274 Sep  1  2019 '08.Pineywood Hills.flac'
-rw-r--r-- 1 root root 34014293 Sep  1  2019 '09.Vincent (Starry, Starry Night).flac'
-rw-r--r-- 1 root root 26663584 Sep  1  2019  10.Stealin.flac
-rw-r--r-- 1 root root 15737114 Sep  1  2019 '11.What A Wonderful World.flac'
-rw-r--r-- 1 root root      301 Sep  1  2019 'A Hobos Dulcimer.m3u'
-rw-r--r-- 1 root root    98205 Sep  1  2019  Folder.jpg

pi@moodelr:~ $ file "/media/MUSIC/FOLK/Brian the Folksinger-A Hobos Dulcimer/Folder.jpg"
/media/MUSIC/FOLK/Brian the Folksinger-A Hobos Dulcimer/Folder.jpg: JPEG image data, JFIF standard 1.01, resolution (DPI), density 300x300, segment length 16, baseline, precision 8, 600x600, components 3

There are no dot files or subdirectories. The Folder.jpg file contains the album's cover art. I used the file command to see if the file is legit jpeg.
[Note that the cover art file can have only certain names (Cover, cover, Folder, folder) and certain image-type file extensions (.gif, .jpg, .jpeg, .png, .tif, .tiff)].

You can determine quickly if you have embedded cover art in a track by using the mediainfo command. No tracks in the above  album contain embedded cover art so let's test the contents of Tim's Stereo Test directory instead:

Code:

pi@moode:~ $ ls -laR "/mnt/SDCARD/Stereo Test"
'/mnt/SDCARD/Stereo Test':
total 2080
drwxr-xr-x 2 root root    4096 Dec  7 22:36 .
drwxr-xr-x 3 root root    4096 Apr  2 16:22 ..
-rw-r--r-- 1 root root 2120405 Dec  7 22:36 LRMonoPhase4.flac
pi@moode:~ $ mediainfo "/mnt/SDCARD/Stereo Test/LRMonoPhase4.flac"
General
Complete name                            : /mnt/SDCARD/Stereo Test/LRMonoPhase4.flac
Format                                   : FLAC
Format/Info                              : Free Lossless Audio Codec
File size                                : 2.02 MiB
Duration                                 : 38 s 761 ms
Overall bit rate mode                    : Variable
Overall bit rate                         : 438 kb/s
Album                                    : Stereo Test
Album/Performer                          : Koz
Track name                               : LR Channel And Phase
Track name/Position                      : 1
Track name/Total                         : 1
Performer                                : Koz
Genre                                    : Utilities
Recorded date                            : 1997
Writing application                      : X Lossless Decoder 20161007
Cover                                    : Yes
Cover type                               : Cover (front)
Cover MIME                               : image/png
TITLESORT                                : LR Channel And Phase
ARTISTSORT                               : Koz
ALBUMSORT                                : Stereo Test

Audio
Format                                   : FLAC
Format/Info                              : Free Lossless Audio Codec
Duration                                 : 38 s 761 ms
Bit rate mode                            : Variable
Bit rate                                 : 431 kb/s
Channel(s)                               : 2 channels
Channel layout                           : L R
Sampling rate                            : 48.0 kHz
Bit depth                                : 16 bits
Compression mode                         : Lossless
Stream size                              : 1.99 MiB (99%)
Writing library                          : libFLAC 1.3.1 (UTC 2014-11-25)

and you can see it contains cover art in png format.

All this is just exploratory surgery by which we hope to get to a root cause of your issue. Like exploratory surgery, it can get messy.

Regards,
Kent

[Nautilus]

@Nautilus

I see you have changed from the default 32-bit kernel to what is for us still an experimental 64-bit kernel. I strongly suggest you revert to the default 32-bit kernel until everything is working to your satisfaction. 

As for those Zend errors

Code:

thmcache: mp3: Zend media exception: File does not contain ID3v2 tag of supported version: v2.2

they are relatively harmless in the grand scheme of things but you'll have a more satisfactory use of moOde Library Tag and Album views if you check the tracks using a tool like Mp3tag or similar (you can do a web search on music tagging) and correct any metadata issues.

You haven't said how you associate cover art with albums. Is cover art embedded as metadata in each track? Is a cover art file included in each album directory?

If "USB/Discoteca/LCD Soundsystem/This Is Happening" is "the first album that stops getting the artwork shown" then you could use one of the following commands to explore the associated file system directory, either the longform

Code:

ls "/var/lib/mpd/music/USB/Discoteca/LCD Soundsystem/This Is Happening"

or the shortcut

Code:

ls "/media/Discoteca/LCD Soundsystem/This Is Happening"

[note that in Linux one needs to use balanced single or double quotes to protect space characters when working from the command shell. Instead, one can escape each space character with a backslash but that gets tedious.]

The output of the command should be a listing of files, pesky dotted files, and subdirectories with permissions, sizes, etc. Post it here.

For example, here's an album (from a street performer I stopped and listened to; he gave me 30 minutes of his time in music and discussion, I bought his self-published CD) in one of my test directories

Code:

pi@moode:~ $ ls -laR "/media/MUSIC/FOLK/Brian the Folksinger-A Hobos Dulcimer"
'/media/MUSIC/FOLK/Brian the Folksinger-A Hobos Dulcimer':
total 214496
drwxr-xr-x 2 root root    32768 Sep  1  2019  .
drwxr-xr-x 5 root root    32768 Aug  4  2020  ..
-rw-r--r-- 1 root root 16129115 Sep  1  2019 '01.A Hobos Dulcimer.flac'
-rw-r--r-- 1 root root 20804658 Sep  1  2019 '02.A Satisfied Mind.flac'
-rw-r--r-- 1 root root 11546441 Sep  1  2019 '03.Pack Up Your Sorrows.flac'
-rw-r--r-- 1 root root 15740724 Sep  1  2019 '04.Twinkle, Twinkle Little Star.flac'
-rw-r--r-- 1 root root 17738482 Sep  1  2019 '05.Rich Mans Woman Blues.flac'
-rw-r--r-- 1 root root 25762063 Sep  1  2019 '06.Four Strong Winds.flac'
-rw-r--r-- 1 root root 20661346 Sep  1  2019  07.Evangelina.flac
-rw-r--r-- 1 root root 14418274 Sep  1  2019 '08.Pineywood Hills.flac'
-rw-r--r-- 1 root root 34014293 Sep  1  2019 '09.Vincent (Starry, Starry Night).flac'
-rw-r--r-- 1 root root 26663584 Sep  1  2019  10.Stealin.flac
-rw-r--r-- 1 root root 15737114 Sep  1  2019 '11.What A Wonderful World.flac'
-rw-r--r-- 1 root root      301 Sep  1  2019 'A Hobos Dulcimer.m3u'
-rw-r--r-- 1 root root    98205 Sep  1  2019  Folder.jpg

pi@moodelr:~ $ file "/media/MUSIC/FOLK/Brian the Folksinger-A Hobos Dulcimer/Folder.jpg"
/media/MUSIC/FOLK/Brian the Folksinger-A Hobos Dulcimer/Folder.jpg: JPEG image data, JFIF standard 1.01, resolution (DPI), density 300x300, segment length 16, baseline, precision 8, 600x600, components 3

There are no dot files or subdirectories. The Folder.jpg file contains the album's cover art. I used the file command to see if the file is legit jpeg.
[Note that the cover art file can have only certain names (Cover, cover, Folder, folder) and certain image-type file extensions (.gif, .jpg, .jpeg, .png, .tif, .tiff)].

You can determine quickly if you have embedded cover art in a track by using the mediainfo command. No tracks in the above  album contain embedded cover art so let's test the contents of Tim's Stereo Test directory instead:

Code:

pi@moode:~ $ ls -laR "/mnt/SDCARD/Stereo Test"
'/mnt/SDCARD/Stereo Test':
total 2080
drwxr-xr-x 2 root root    4096 Dec  7 22:36 .
drwxr-xr-x 3 root root    4096 Apr  2 16:22 ..
-rw-r--r-- 1 root root 2120405 Dec  7 22:36 LRMonoPhase4.flac
pi@moode:~ $ mediainfo "/mnt/SDCARD/Stereo Test/LRMonoPhase4.flac"
General
Complete name                            : /mnt/SDCARD/Stereo Test/LRMonoPhase4.flac
Format                                   : FLAC
Format/Info                              : Free Lossless Audio Codec
File size                                : 2.02 MiB
Duration                                 : 38 s 761 ms
Overall bit rate mode                    : Variable
Overall bit rate                         : 438 kb/s
Album                                    : Stereo Test
Album/Performer                          : Koz
Track name                               : LR Channel And Phase
Track name/Position                      : 1
Track name/Total                         : 1
Performer                                : Koz
Genre                                    : Utilities
Recorded date                            : 1997
Writing application                      : X Lossless Decoder 20161007
Cover                                    : Yes
Cover type                               : Cover (front)
Cover MIME                               : image/png
TITLESORT                                : LR Channel And Phase
ARTISTSORT                               : Koz
ALBUMSORT                                : Stereo Test

Audio
Format                                   : FLAC
Format/Info                              : Free Lossless Audio Codec
Duration                                 : 38 s 761 ms
Bit rate mode                            : Variable
Bit rate                                 : 431 kb/s
Channel(s)                               : 2 channels
Channel layout                           : L R
Sampling rate                            : 48.0 kHz
Bit depth                                : 16 bits
Compression mode                         : Lossless
Stream size                              : 1.99 MiB (99%)
Writing library                          : libFLAC 1.3.1 (UTC 2014-11-25)

and you can see it contains cover art in png format.

All this is just exploratory surgery by which we hope to get to a root cause of your issue. Like exploratory surgery, it can get messy.

Regards,
Kent

Many thanks for your extended response.

I use Matadatics (latest version) and the cover art (mostly .jpg or .jpeg) are embedded in the audio files.

Of the two commands you recommended, only the second one worked:

pi@moode:~ $ ls "/media/Discoteca/LCD Soundsystem/This Is Happening"
'01 Dance Yrself Clean.m4a'  '06 You Wanted A Hit.m4a'
'02 Drunk Girls.m4a'         '07 Pow Pow.m4a'
'03 One Touch.m4a'           "08 Somebody's Calling Me.m4a"
'04 All I Want.m4a'          '09 Home.m4a'
'05 I Can Change.m4a'
pi@moode:~ $

My music Library works fine on PiCorePlayer, but for some reason a small number of them (15%) does not work uo to the LCD Soundsystem album, and barely any one works after that. It seems a scanning problem rather than anything else...

I will revert to 32bits, but the problem started in 32bits, and I changed to 64bits hoping that may made a (positive) difference, but it made none.

[Tim Curtis]

In Tag view do the Album and Track counts listed below the "Music Collection" cover reflect your collection?

If so then it would indicate MPD indexed the collection successfully and the issue is isolated to thumbnail generation either in the script that generates the input list for the thumbnail generator, the generator itself or some data thats causing unexpected issues.

[TheOldPresbyope]

@Nautilus

Hmmm, M4A files (e.g., MPEG-4 with audio but not video). Do all the tracks which don't display cover art happen to be M4a files? This is a container format with little industry-wide standardization of content. I suspect many people believe that whatever iTunes does is "the standard." The few test tracks I've downloaded seem to work in moOde vis-a-vis metadata and embedded cover art.

Here's data from a test track I downloaded from Hyperion some time ago; I expect most iTunes tracks would be similar.

Code:

pi@moode:/media/MUSIC/SampleTracks/Hyperion/Orchestral $ mediainfo 18*M4A
General
Complete name                            : 18 MacCunn The Lay of the Last Minstrel - Part 2 Final chorus O Caledonia! stern and wild.M4A
Format                                   : MPEG-4
Format profile                           : Apple audio with iTunes info
Codec ID                                 : M4A  (M4A /mp42/isom)
File size                                : 14.5 MiB
Duration                                 : 2 min 54 s
Overall bit rate mode                    : Variable
Overall bit rate                         : 696 kb/s
Album                                    : Maccunn: Land of the Mountain & the Flood
Album/Performer                          : Martyn Brabbins: BBC Scottish Symphony Orchestra
Part/Position                            : 1
Part/Total                               : 1
Track name                               : MacCunn: The Lay of the Last Minstrel - Part 2. Final chorus: O Caledonia! stern and wild
Track name/Position                      : 18
Track name/Total                         : 18
Performer                                : Martyn Brabbins: BBC Scottish Symphony Orchestra
Composer                                 : MacCunn, Hamish (1868-1916)
Genre                                    : Classical
Recorded date                            : 1995
Copyright                                : © Hyperion Records Ltd, London
Cover                                    : Yes
Lyrics                                   : Chorus: O Caledonia! stern and wild, / Meet nurse for a poetic child! / Land of brown heath and shaggy wood, / Land of the mountain and the flood. / Land of my sires! What mortal hand / Can e’er untie the filial band, / That knits me to thy rugged strand! /  / Sir Walter Scott (1771-1832) /  / This concluding recitative and chorus (from MacCunn’s dramatic cantata of 1888) is the vocal expression of the same passage from Scott’s poem which inspired Land of the Mountain and the Flood. No composer was more fitted to attempt this theme than MacCunn. Had not his father-in-law famously painted him as Bonnie Prince Charlie? Was he not handsome in the lists of love as the winning suitor in the painting Two Strings to her Bow? Had not Queen Victoria herself seen in him a likeness to his compatriot Byron, only more handsome? Was he not the epitome of a modern bardic revival, not hoary-headed and despairing, but youthful, daring to re-assert what the old bard recalled only as a lost world? / So it is that MacCunn makes no doomed attempt to resurrect a bardic manner. His is a triumphant cry of modern nationhood, cultural and political, and his setting is a thrilling monument to the memory of his genius, spent to extend the road of Scotland’s cultural destiny, fearless and still bearing the brand of youth. / from notes by John Purser © 1995 /  / Album notes: / Hamish MacCunn: the name itself is a kind of bold statement, and if ever there was a composer who emerged from the glens and firths of Scotland, fully armed, the MacCunn was that person. Yet this is the first recording devoted solely to his work and, with the exception of Land of the Mountain and the Flood, the first of any of his orchestral music. / John Purser © 1995
UPC                                      : 0034571168159
Source                                   : CD (Lossless) >> CD  (Lossless) [wav]
cond                                     : Martyn Brabbins

Audio
ID                                       : 1
Format                                   : ALAC
Codec ID                                 : alac
Codec ID/Info                            : Apple Lossless Audio Codec
Duration                                 : 2 min 54 s
Source duration                          : 2 min 54 s
Source_Duration_LastFrame                : -13 ms
Bit rate mode                            : Variable
Bit rate                                 : 684 kb/s
Channel(s)                               : 2 channels
Sampling rate                            : 44.1 kHz
Bit depth                                : 16 bits
Stream size                              : 14.3 MiB (98%)
Source stream size                       : 14.3 MiB (98%)
Language                                 : English
mdhd_Duration                            : 174800

As you can see, mediainfo says the file contains cover art but, because of the nature of M4A apparently, it doesn't try to figure out the image format of the cover art. Perhaps @Tim Curtis can comment on image formats embedded in M4A which are acceptable to moOde's cover art routines. I'd rather not try to interpret the applicable php module(s).

Do you see any log messages containing "coverart: m4a:" or "thmcache: m4a"?

I'll be away from my keyboard for a while to pack more boxes. Maybe others will pick up the chase in the meantime.

Regards,
Kent

ETA - PS I didn't notice Tim's reply before I posted this

[Nautilus]

In Tag view do the Album and Track counts listed below the "Music Collection" cover reflect your collection?

If so then it would indicate MPD indexed the collection successfully and the issue is isolated to thumbnail generation either in the script that generates the input list for the thumbnail generator, the generator itself or some data thats causing unexpected issues.

Hello again Tim, and thanks for your patience...

The albums are all there, but the art cover doesn't show up under albums beyond the LCD Soundsystem album, even if under tag view some of them are visible

   

[Tim Curtis]

Back in post #12 it appears the log abruptly ended w/o printing the "Done:" line showing the results and counts of thumbnail generation. This suggests the thumbnail generator crashed for some reason.

Code:

.
.
.
20210603 100006 thmcache: mp3: Zend media exception: File does not contain ID3v2 tag of supported version: v2.2
20210603 100008 thmcache: mp3: /var/lib/mpd/music/USB/Discoteca/Jethro Tull/Collection/13 Living in the Past.mp3
20210603 100008 thmcache: mp3: Zend media exception: File does not contain ID3v2 tag
pi@moode:~ $

Here's what it should look like. Notice the "Done:" line at the end showing the stats. This was run on one of my small mixed content test collections. Some of the files have bad metadata.

Code:

20210603 162054 worker: Job regen_thmcache
20210603 162054 thmcache: Start
20210603 162054 thmcache: Priority: Embedded cover
20210603 162054 thmcache: Res,Qual: Auto
20210603 162054 thmcache: Px ratio: 1
20210603 162054 thmcache: Th width: 100
20210603 162054 thmcache: Thm qual: 75
20210603 162054 thmcache: Scanning: NAS, SDCARD, UPNP, VFAT128
20210603 162102 thmcache: flac: /var/lib/mpd/music/USB/VFAT128/Test_mixed/Frans Meerhoff/Test2/Mary Wells - My Guy.flac
20210603 162102 thmcache: flac: Zend media exception: Not a valid FLAC bitstream
20210603 162107 thmcache: flac: /var/lib/mpd/music/USB/VFAT128/Test_mixed/Runaljod - Gap Var Ginnunga/12 - Dagr.flac
20210603 162107 thmcache: flac: Zend media exception: Not a valid FLAC bitstream
20210603 162109 thmcache: Done: 113 folders scanned, 112 thumbs created, 1 already in cache.
pi@rp2:~ $

As @DRONE7 suggested earlier, remove the folder that you suspect might be the involve in the crash and then regenerate the thumbnails.
There are prolly other ways to troubleshoot but I'd try that first.

[Nautilus]

Back in post #12 it appears the log abruptly ended w/o printing the "Done:" line showing the results and counts of thumbnail generation. This suggests the thumbnail generator crashed for some reason.

Code:

.
.
.
20210603 100006 thmcache: mp3: Zend media exception: File does not contain ID3v2 tag of supported version: v2.2
20210603 100008 thmcache: mp3: /var/lib/mpd/music/USB/Discoteca/Jethro Tull/Collection/13 Living in the Past.mp3
20210603 100008 thmcache: mp3: Zend media exception: File does not contain ID3v2 tag
pi@moode:~ $

Here's what it should look like. Notice the "Done:" line at the end showing the stats. This was run on one of my small mixed content test collections. Some of the files have bad metadata.

Code:

20210603 162054 worker: Job regen_thmcache
20210603 162054 thmcache: Start
20210603 162054 thmcache: Priority: Embedded cover
20210603 162054 thmcache: Res,Qual: Auto
20210603 162054 thmcache: Px ratio: 1
20210603 162054 thmcache: Th width: 100
20210603 162054 thmcache: Thm qual: 75
20210603 162054 thmcache: Scanning: NAS, SDCARD, UPNP, VFAT128
20210603 162102 thmcache: flac: /var/lib/mpd/music/USB/VFAT128/Test_mixed/Frans Meerhoff/Test2/Mary Wells - My Guy.flac
20210603 162102 thmcache: flac: Zend media exception: Not a valid FLAC bitstream
20210603 162107 thmcache: flac: /var/lib/mpd/music/USB/VFAT128/Test_mixed/Runaljod - Gap Var Ginnunga/12 - Dagr.flac
20210603 162107 thmcache: flac: Zend media exception: Not a valid FLAC bitstream
20210603 162109 thmcache: Done: 113 folders scanned, 112 thumbs created, 1 already in cache.
pi@rp2:~ $

As @DRONE7 suggested earlier, remove the folder that you suspect might be the involve in the crash and then regenerate the thumbnails.
There are prolly other ways to troubleshoot but I'd try that first.

Well, not successful at all:

1. turned off MoOde
   
2. removed the USN drive
   
3. connected to my Mac
   
4. removed the album where the scan got stacked before
   
5. re-connected the USB drive to the Pi4
   
6. re-started the Pi4
   
7. and the USB drive is gone!
   
8. no longer have access to my music library
   

  I have rebooted the Pi4 three times, tried to rebuild the Library another three times

  Now what?

[DRONE7]

Put the USB drive back in your MAC...check the files are there then make sure you safely/properly remove it.
Then plug it back into the Pi...try another USB port (and not the USB3 ports)
Check that it us found...you can run  from a terminal if needed .

Code:

lsusb

Go to the library tab and do a full regenerate.