[Shotwell] How to remove metadata from photo files?

[Stefan Monnier]

> (I know rsync and unison have very efficient algorithms to only transfer
> the modified part of a file --

Actually, AFAIK this only works if the unmodified part of the file stays
at the same place in the file (or moves by a distance that is a multiple
of the block size used by rsync/unison).  For this reason it's good for
the metadata to be stored in a "metadata area" that grows by "large"
increments (like 4KB at a time).  I don't know if Shotwell does that,
but at least metaflac does it for Flac files.

> but when doing version control, this still causes troubles because
> neither Git nor any other VCS that I know of is capable of efficiently
> storing multiple version of binary files -- they just keep full copies
> for every version, which costs a lot of disk space)

Actually, that is not true, Svn, Git, Bzr and probably most other modern
VCS store their data using a "binary diff" algorithm, which can be
thought of as a variant of dictionary compression where the base
dictionary is the other file.  So they tend to react very well to
changes such as metadata as long as the rest of the bytes are left
unchanged.  They may even behave better than rsync since they easily
handle cases where the unchanged bytes are moved in the file.


        Stefan