(windows) command line m4a tagger?

[simoncn]

The spec seems clear and I don't see any reason why I shouldn't implement it. This won't prevent the current approach of having multiple values encoded as ----/mean/data from working as well.

[simoncn]

(21-11-2017 22:44)skeptic Mike Wrote:  Thanks for looking at that. It is interesting. I'll prepare a sample file. I don't know how useful it will be if no available taggers do this.

I have implemented and tested this change. I used a hex editor to create a suitable test file, so I don't need the sample file now. Thanks for letting me know about this issue.

[skeptic Mike]

(21-11-2017 22:51)paultaylor Wrote:  

(21-11-2017 22:44)skeptic Mike Wrote:  If all available programs make multiple atoms, then it may be better to do nothing. I don't know for sure, but I have the impression that mp3tag is likely the most popular tagger with working multi value support. Perhaps Paul knows more about this, as he must have to rewrite broken tags.

I would agree with Mike that other than for completeness there does not seem to be much point in supporting the way AtomicParsley does things since I don't know of any other applications that support this way so even if MinimServer understands it if you want to use another tool like Mp3Tag to edit your tags it will not support it. Unsuprisngly my own taggers (SongKong/Jaikoz) do multiple values the same way that MP3Tag does them.

I've just looked at the python mutagen library. This does the same as my hacked AtomicParsley, in that it puts multiple data atoms under the name. It does this for the standard tags ('\xa9wrt etc) as well. What's more if you have mp3tag style multiple tags, it reads them happily, but writes them back in the multiple data atom form when you force it to rewrite the tags, e.g. by adding an additional different tag.

The mutagen library is supported, and although it doesn't seem to be used to create multiple value tags in Ex Falso, I know that it's used in puddletag. puddletag's author's suggest that it is mostly functionally equivalent to mp3tag, so I wonder if it supports multiple value m4a tags.

mp4 tags seem to be in such a mess. And that's without considering the unspeakable things that windows explorer does to create it's own private tags.

[simoncn]

Thanks for the test file. The new version of MinimServer (not yet released) is reading the multivalued SINGER tag correctly:

SINGER=Christopher Purves
SINGER=Roberta Invernizzi
SINGER=Sonia Prina

I'm not sure why you think mp4 tags are in such a mess. The spec supports multiple values for all tag names and there are taggers and servers that correctly implement the spec.

[skeptic Mike]

(23-11-2017 10:20)simoncn Wrote:  Thanks for the test file. The new version of MinimServer (not yet released) is reading the multivalued SINGER tag correctly:

SINGER=Christopher Purves
SINGER=Roberta Invernizzi
SINGER=Sonia Prina

I'm not sure why you think mp4 tags are in such a mess. The spec supports multiple values for all tag names and there are taggers and servers that correctly implement the spec.

Thankyou, that's most helpful.

I think that mp4 tags are ok, it's the difficulty I've had finding tagging programs that work, and support multiple values. I think that relates to the difficulty with identifying the formal specification, and confusing it with the iTunes tag set - which seem to be a specific implementation. Obviously my requirement for a command line tagger makes the search more difficult. However, most of the GUI taggers I've tried don't support multiple values. Perhaps I've not looked at the right ones. mp3Tag will quietly destroy the compliant tags I've (accidentally) produced. I guess I should submit a bug report to mp3tag about that.

Is there a list of taggers that correctly implement the full spec that Minimserver can use?

Brief testing of puddletag on my poor server shows that it will produce multiple tags (in the mutagen format) The UI looks rather like mp3tag, and allows one to add arbitrary tags in the same way.

[simoncn]

I think destroying valid tags is a very serious bug and you should definitely report it to the author of Mp3tag.

I don't have many mp4 files myself and I am not familiar with how different taggers treat multivalued tags in these files. Perhaps other users with mp4 libraries can share their experience.

In practice, the way these issues are resolved is by users such as yourself coming across problems and reporting them to authors of servers or taggers who will then (hopefully) fix them by implementing the spec more correctly and completely, which benefits all users.

[paultaylor]

(23-11-2017 19:04)skeptic Mike Wrote:  mp3Tag will quietly destroy the compliant tags I've (accidentally) produced.

Does it actually delete them ! or just convert them to multiple ---- atom format ?

MinimServer only has to read the metadata, but if you are using a tool to write the metadata then it may rewrite the metadata, change order of the metadata tags ectera but it should not delete anything.

[paultaylor]

(23-11-2017 10:20)simoncn Wrote:  I'm not sure why you think mp4 tags are in such a mess. The spec supports multiple values for all tag names and there are taggers and servers that correctly implement the spec.

It seems there are two ways to do the same thing, that always causes problems. In a similar way Wav files support both INFO LIST and ID3 metadata blocks makes things more difficult.

[simoncn]

In life, there are often many ways to do the same thing.

[simoncn]

The problem with LIST/INFO vs ID3 tagging schemes is a bit different because of the possibility of having both schemes in the same file and different servers choosing a different scheme to read in preference to the other. This causes inconsistent results unless the information in both schemes is identical.