There are two methods for how to get offline synced lyrics.
Find the time stamped lyrics for your songs which don't have lyrics already. A time stamped lyrics looks like this, "[00:04:02] Some lyrics text" for example.
Copy these time stamped lyrics.
Open 1Music Player and head to the song synced lyrics editor.
Paste the lyrics there normally and exit the editor
Open lyrics and you should see your time stamped lyrics there.
Find the ".lrc" files for your songs which doesn't have lyrics already.
A ".lrc" is like a text file which contains the time stamped lyrics for example, "[00:04:02] Some lyrics text"
Now you have to rename the file you created in this way: - .lrc or for better matching copy the and the from the tag editor and then rename the file.
You have to copy or move this file into a location on the SD Card: whatever_sdcard/1Music Player/lyrics/ and paste it there.
Finally you will be able to see the lyrics working.
If you want to skip to particular time stamp, simply scroll to the time stamp from where you want to start from and a 'Play' icon will appear left to the particular stamp. Tap on play button to play from there.
Last.fm has disabled the download of artist's images for the time being, whether functionality for this will be restored in future is uncertain.
Settings -> Look and feel -> Select your theme.
Settings -> Other -> Last added playlist interval -> Select an option from the list.
Settings -> Personalize -> Fullscreen controls -> Enable (this will only be visible when songs are playing from 1Music Player).
Settings -> Images -> Ignore media store covers -> Enable
1Music Player uses the native media player that comes with your Android phone, so as long as a file type is supported by your phone, it's supported by 1Music Player.
1Music Player is image intensive, it keeps images in the cache for quick loading.
Clear the app's cache and data.
Reinstalling the app should fix this issue.
Change the theme to Black or Dark and change it back to what you had before.
Try checking up if those songs are not less than 30 seconds, if so head to settings -> other -> filter song duration. Put this to zero and see the songs should start appearing in the library.
If this doesn't work out for you, re-scanning the media folder should help and subsequently rebooting the device to refresh media store.
At last resort, If nothing worked and your audio files are stored in SD card. Try moving them to internal memory then back to SD card.
Playlist/Playlist songs disappearing is based on android media store system. Save those playlist as file(Tap on three dot menu next to available playlist and save as file) and it should get fixed.
If you are seeing duplication of songs in the library or no songs at all, then it's because of Media Store issue which got affected by some other app.
To fix this:
• Head to your device settings
• Open up "Apps & notifications" (This name depends from ROM to ROM)
• Find 'Media storage' app and clear storage (both data and cache) of it.
• Then open 1Music Player app and manually scan your music from your storage.
• Reboot the device to refresh media store (Not sure if this is necessary)
NOTE: Don't panic when you will open 1Music Player and see "Zero" songs there in the library. It's because you cleared Media Store which is responsible for recognizing files on your device.