[Ben]

The size of my back-up library is 10.7gb, at least 90% of that are mp3s.
For handling reasons and because the tablet's capacity is pretty much exhausted, I want to reduce the library size.
dBpoweramp batch-compresses mp3s to say 30% (even more is possible but I'd settle for a 70% reduction).
However, I haven't found a way to compress the MSP embedded mp3s in one batch.
I tried to copy the entire android zubersoft "files" folder to the PC, but that stopped somewhere, at letter C, Windows probably didn't like a specific android song folder name. And quite a few copied song folders were empty, while on the tablet they're not. The idea was to do the batch compression on the PC (dBpoweramp doesn't allow to access the tablet directly) and copy the whole thing back to the tablet, hoping MSP will not "notice", except that the library is now ~ 4gb in size.

Can anyone recommend a method?

Thank you!
Ben

[itsme]

MSP has a checkbox to exclude audio files from the backup

[BRX]

I think your idea to compress the mp3s on the PC and copy them back is the right one (regardless of excluding them from the backup).

Have you tried a dedicated copy program to copy the folders to the PC (something like teracopy for instance)? I also can recommend the program Beyond Compare (which isn't free but well worth the money) which not only is an excellent comparison and checking tool but also very reliable syncs and copies folders and files.

[Ben]

Thanks BRX, I'll try your suggestions!
itsme, the audiofiles should, in mycase, always be part of the library.
I copy the entire library regularly onto my buddy's tablet, he wouldn't want to miss the audio files ☺.
Also, from time to time I clear the library from my tablet and install the fresh backup.
I do this as pdf and mp3 files are saved at unexpected places sometimes, or old files not removed, and this is a good way to clean this up.

[Ben]

Tried it with teracopy but that didn't work for me.
By copying the song folders from the tablet to the PC, in chunks of around 200, and using the batch converter dBpoweramp to compress mp3s to 64 kbit/s, then deleting the folders on the tablet and copy the ones from the PC, now with compressed mp3s, back to the tablet, the library was reduced from 10.7 to 3.4 gb. The whole process took 90 minutes, incl. bug fixes:
Only very few glitches, a compression failed here and there, or MSP didn't find the pdf and mp3 of a song, but that was easy to fix.
I don't notice loss in quality through the tablet speakers.
To handle 3.4 instead of 10.7 gb is significantly easier.
Thanks again.

[sciurius]

Compressing MP3... You mean by lossfull reencoding to a very low baudrate?

[GraemeJ]

Compressing MP3... You mean by lossfull reencoding to a very low baudrate?

I was wondering about that - the end quality must be pretty dreadful!  It might not be too apparent on the poor audio of the average tablet, but it's not going to work too well when played through any half-way decent system.

[Ben]

The sound on the tablet speakers didn't really suffer, but no, I wouldn't try to play 64 kbit/s on a PA.
Where this is necessary I'll just reinstall the magnificent 256 kbit or whatever it was, for those specific songs.
Granted, this is not a thread for audiophiles!
When I need more than the tablet speakers, and much less than a PA, I connect with the UE Roll (bluetooth), it can quickly be attached to almost anything and doesn't mind being maltreated (liquids, dirt, dust).