Sync / copy only differences in files?

[Sharky-PI]

Hi all.

Every time I play a song on my PC, my music player updates the metadata to add 1 to the playcount, and potentially also the song rating if I change it. There are pros & cons to this but that's the way I want it.

Having copied all of my music collection from PC to NAS either by external drive or manual upload, I now have LOADS of files which show red diffs, i.e. they're basically the same, except for a ~100 byte extra bit of ID3 metadata.

Is it possible to push only the changes from PC to NAS, rather than overwriting the whole file?

Thanks!

[Aaron]

Hello,

No, we only support copying the full file. We can compare the metadata, and optionally ignore these fields if you would like to ignore these changes and only copy the file if another change is made, using a rules-based comparison.

[Sharky-PI]

Thanks Aaron. Ok, shame. Is that something that's on your guys' roadmap at all? IDK if it's a feature many people would be interested in... IDK if the additional comparison time would be justified by the network transfer time saving - I guess it would depend on the scenario. But then I suppose if you could do a 2nd pass comparison, i.e. "compare all red results at a file-structure level", that could then open up the possibility for "push diffs only" vs "push whole file".

Thanks for the reply dude.

[Aaron]

Hello,

The key is the detection of the needed alignment, which is a large project that is on our wishlist but not one we'll be able to tackle soon. The current version only aligns based on name first, and then runs the comparison scan on those pairs. After that project, we could then look into touching the file name to help get them to match on the aligned pairs.

[Sharky-PI]

Hi Aaron, not sure if this reply pertained more to the other thread? IMO the alignment / matching / filename pairing is fine, or at least, not necessarily related to this issue. I figure this issue would be using something similar to the within-file diff checking that seems to be in play on text files, and indeed pictures. I don't know if it would make more sense to look at the problem on a per-filetype basis or as a whole. My specific issue (ID3 metadata w/in MP3s) is potentially only a small subset of the total potential solution, but maybe it'd be easier to solve it as lots of little solutions, if e.g. for the ID3/MP3 issue, the diffs can be expected to align themselves to certain areas of the files and so an algorithmic solution might not be especially tough. That said, maybe the existing tech for whole-filedata-comparison makes that low hanging fruit - essentially this is not unlike version control right? The newer MP3 has a diff with a few bytes/kilobytes changed, and only those changes are pushed to the slave (e.g. NAS/right hand pane).

Just thinking out loud - you're the expert on this stuff!

[Aaron]

Ah, yes, sorry about that mix up. Editing mp3 tags to allow this kind of update is on our wishlist, but we currently only support reading, not setting, this information.

[Sharky-PI]

That would be really cool. Thanks Aaron, I'll keep an eye out for updates.