I think I understand now. Since in this case we have already opened the file in music open activity we can assume it is probably an audio file, so in checking the file type we should not expect to see video.

`checkFilename()` only looks at the extension of the file, so it can not be very effective. The best thing I can think of to do is to check the extension will map to one of the supported audio types: "type": ["audio/mpeg", "audio/ogg", "audio/mp4", "audio/amr"]. To do that we can not use `MimeMapper.guessTypeFromExtension()` so the solution would be to write another mapping function (local or share?) to check if an extension (example ogg) *can* be an audio file. Even then, that will not be a very satisfactory test for an audio file.

We can not look at the blob to check it's mime type, can we?