[php] Which mime type should I use for mp3

I'm trying to decide which mime type to choose for returning mp3 data (served up by php)

according to this listing of mime types: http://www.webmaster-toolkit.com/mime-types.shtml

.mp3    audio/mpeg3
.mp3    audio/x-mpeg-3
.mp3    video/mpeg
.mp3    video/x-mpeg

What are the difference between these, and which should I use?

You should always use audio/mpeg, because firefox cannot play audio/mpeg3 files

The standard way is to use audio/mpeg which is something like this in your PHP header function ...

header('Content-Type: audio/mpeg');

I had a problem with mime types and where making tests for few file types. It looks like each browser sends it's variation of a mime type for a specific file. I was trying to upload mp3 and zip files with open source php class, that what I have found:

• Firefox (mp3): audio/mpeg
• Firefox (zip): application/zip
• Chrome (mp3): audio/mp3
• Chrome (zip): application/octet-stream
• Opera (mp3): audio/mp3
• Opera (zip): application/octet-stream
• IE (mp3): audio/mpeg
• IE (zip): application/x-zip-compressed

So if you need several file types to upload, you better make some tests so that every browser could upload a file and pass mime type check.

Use .mp3 audio/mpeg, that's the one I always used. I guess others are just aliases.

mp3 files sometimes throw strange mime types as per this answer: https://stackoverflow.com/a/2755288/14482130

If you are doing some user validation do not allow 'application/octet-stream' or 'application/x-zip-compressed' as suggested above since they can contain be .exe or other potentially dangerous files.

In order to validate when mime type gives a false negative you can use fleep as per this answer https://stackoverflow.com/a/52570299/14482130 to finish the validation.