Discrepancy between allowed upload file types and usable types

[mzur]

The user storage module allows file uploads based on the file MIME types. The volume file browser, however, uses the file endings to filter the displayed files. Also, sometimes the file MIME type changes in unexpected ways. Concrete example:

A user uploaded a file with the .m4v ending but which had MIME type video/mp4. This file can be played in the browser and the file upload allowed the file based on the MIME type. When the file was transferred to the object storage, the MIME type was automatically changed to video/x-m4v however. So now the file will no longer be displayed in the volume file browser because the .m4v file ending is not supported and also the video would not be processed any more because it now has the unsupported video/x-m4v MIME type. But the user did nothing wrong, as the original video file is web-compatible.

What to do here? Allow .m4v as well as video/x-m4v? But there can be videos with video/x-m4v with proprietary audio codecs as far as I have read. These are irrelevant for BIIGLE, though. Or should we better synchronize the allowed files in the upload and volume file browser? Maybe we should check the MIME type and the file ending in the upload?