I have got some m4a files from the same source. Some are editable, some are not.
I think the error message is way too generic. Something like "Cannot write tags to file "Foo.m4a" in folder "bar"".
I think it doesn't help to resolve the issue and as a trial is not so promising.
If you have logs, why don't you put a reference to them so that one may try to find a solution?
What has happend on the way between the source and your target?
There are a number of threads that deal with write problems to m4a files.
Perhaps you find indicators that help you to overcome your problem. Just as examples:
I, those were already provided in the suggestions list while writing the new topic. No solution was found.
My point is that maybe a log can help. A generic message is not helping at all.
Can you maybe provide one file as an example? I can then try to analyze it and see if I can improve the error message in those cases. There is no log for that at the moment.
However, most of the time it's a stream written by a faulty encoder, where even a error message would be of much help because of the very technical nature of the issue.
Foobar says about the file with the name "notWorking.m4a": Unable to open item for playback (Unsupported format or corrupted file (invalid or incomplete data)). So that file does not even play.
Thanks for the example file. One indication that something might be a little bit off with that file is, that there are no information fields displayed (e.g., length or bitrate).
I've had a look at the file and it's a WebM file (not an M4A file). The fact that it's working with a different program/service means, that they have either less strict analysis of the file's content (which would result in garbage output) or use format-detection not based on the file extension but on the file's contents.
Ok. Got it. As I mentioned before, they are both generated using the same tool, not sure why they ended up having different content. But you are right, Apache Tika reports one as a video/webm file (the one not working) and the other as video/mp4.
Thanks for supporting.
Not sure which language you used to implement the tool, but in Java I would have used Apache Tika to provide some media type detection and provide some user feedback. E.g. "*Cannot write tags to file "Foo.m4a" in folder "bar": the media type is WebM while file extension is M4A, WebM files are not supported.
Then maybe one would have the option to find a converter (or you could think about adding one in your software).
Which tool were you using for that? Producing WebM with a M4A file extension is clearly an issue worth noting.
I'm using C++ for Mp3tag, so no Apache Tika for me. I'm also a little hesitant to implement workarounds for bugs in other software (except for Windows Explorer and iTunes — those are beyond hope). I prefer fixing the original issues, that's I'm asking about the the tool you've used.
@Florian sorry for the late answer. It's an online tool, I actually don't know it by heart, but it could be https://www.clickmp3.com/, so not worth investing more on it.
Don't go for workarounds. For sure providing a better message may help a little bit, but if there are unbearable technical issues then it is not worth it.