Recently we have uploaded three .mp3 files to an existing item to complete a sequence of oral interviews.
Format metadata lists these as .mp3, however type metadata lists them as video/mp4 (Mime Type) and ISO Media, MPEG v4 system, version 1 (File Type/OS). This is in contrast to an earlier file on the item, which has the same format metadata as .mp3, and type metadata as audio/mpeg (Mime) and MPEG ADTS, layer III, v1, 128 kbps, 44.1 kHz, JntStereo (File/OS).
The files in question, on our home server before uploading to Omeka, are both .mp3, were both processed from original tapes to .wav and then to .mp3, have bit rates of 128kbps, and are otherwise unremarkable in difference. The new files are longer than the original one (two files approximately 45 minutes in length, one approximately 17 minutes in length - original is approximately 8 minutes), but besides length and subsequent size, there is no practical difference between these files. Omeka gives no error report, because the file upload itself is going off without a hitch.
Any ideas on why Omeka would say the newer files are video instead of audio, and how to convince Omeka otherwise, would be greatly appreciated.
Can you share the files themselves, or links to them?
MP3 can be tough to detect sometimes, but it’s rare to have it misdetect as mp4.
Here is a link to one of the files in question.
On uploading it to the file.io service to share, it further listed the file as mpga - I wonder if some background function of our conversion from .wav to .mp3 might have caused an underlying .mpg/mpeg/mpga confusion, which is leading to Omeka thinking we’re uploading an audio-only video file? As an aside, these file conversions were done a couple years before I was here, so I don’t know HOW the audio processing was done at that time.
So yes, that file is an audio file oddly wrapped into the “mp4” container (it can be used for audio and is in some circumstances, but this particular one is odd). This makes it trickier to detect what it is so it’s not surprising that video/mp4 is the best or default guess. The site you uploaded it to actually changes the extension to .mp4 for download, even.
The data actually isn’t MP3 audio, it’s “mp2”, or MPEG audio layer 2, which is less common and less well-supported on its own for browsers to play than MP3, which is “layer 3” audio. That’s probably why it was in this different container in the first place.
Here’s a copy of the file, converted to a normal MP3 file. It should upload more how you’re used to. How you want to proceed from here maybe depends on how many “not really MP3s” you have.
Makes sense, and I was worried about that - it will certainly be an undertaking to go through our other files and figure out which ones have done silly things like that.
Thank you very much!