m4a from android phone recognizes as 'video/mp4', but should 'audio/x-m4a'

[matvey-b]

Sample m4a file

Unix file util output:

matvey-b@laptop-matvey:~/Загрузки$ file sample.m4a 
sample.m4a: ISO Media, MP4 v2 [ISO 14496-14]

p.s. thanks for help 🙂

[bencmbrook]

I know MPEG-4s are tricky to distinguish. Should look into what is resolving here for the above sample file

file-type/core.js

Line 437 in cf34c7b

const brandMajor = uint8ArrayUtf8ByteString(buffer, 8, 12).replace('\0', ' ').trim();

[matvey-b]

I think I misunderstood the problem. In fact, according to this article, this is still an MP4 container 😞 And m4a is a special case of mp4. This all means that your library is working properly.

[bencmbrook]

That's right - file-type is not wrong to say video/mp4, but sometimes it can be more specific, based on the File Type Box (https://en.wikipedia.org/wiki/ISO_base_media_file_format). I checked this particular file and the ftyp is set to mp42, so we can't be more specific for this file. Closing this issue as it's more a matter of the file itself.