When is an mp4 not an mp4?

Question

Al Hatch Author

Level 2

214 points

When is an mp4 not an mp4?

In QuickTime Player, all movies saved as MP4s or exported as MP4s are not equal.

Open two movies at the same time, and export them at the same time, both as an MP4 or as an M4V.

They are the same frame rate and same compression (obviously).

The Media Manager in Joomla 1.6 will fail to upload one of them and complain that it is not a movie file.

Yet it will upload the other and identify it as an MP4. This happens 50% of the time for me.

Clearly, Joomla is looking beyond the file extension and examining some other property of the movie.

What could that other property be? A movie compressed as an H264 MP4 should be exactly the same

as the next movie compressed as an H264 MP4 at the same frame rate, right?

What could cause one not to be recognized as a movie?

Mac Pro 3.0 GHz FCP 7.0.2, Mac OS X (10.6.4), 16 GB RAM

Posted on Apr 22, 2011 3:17 AM

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Answer 1

Jon Walker

Level 6

19,467 points

Apr 22, 2011 5:09 AM in response to Al Hatch

What could that other property be? A movie compressed as an H264 MP4 should be exactly the same as the next movie compressed as an H264 MP4 at the same frame rate, right? What could cause one not to be recognized as a movie?

Haven't the foggiest idea but usually assumed it to be a filtering problem with the site server software. Have noted this occurring seemingly without rhyme nor reason. Try opening the MP4 file in the QT Player (or MPEG Streamclip) and then using the "Save As..." option to copy the data to an MOV file container. In my case, the MOV file container was always accepted.

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