MP4 isn't web friendly

Asked by Vegard Svanberg

The MP4 files produced by Kazam on Ubuntu 13.10 don't work with various web players. It's not just a faststart/metadata issue (it seems), because moving the atoms don't help. The video will just be black while playing, is if there were some codec issues. I've tested on both Ezs3 and Techsmith ( On Youtube it will work, though, as it seems Youtube re-encodes the whole video. The MP4 produced by Youtube will work on the other sites.

Any idea what, why and how to fix it?

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Kazam Screencaster Edit question
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Adam Morris (amorris2003) said :

Try re-installing Kazam or maybe just use WEBM.

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Paul Leonard (paul-leonard) said :

This is still an on-going issue for Kazam.. I love this App, and it's simplicity in using it. As a software Project Manager, also involved in extensive user testing, I rely on this tool a lot.. However, while it's great for me, and works fantastically on my OS, my colleagues using Win or Mac cannot view the MP4 files.

We can advise it is definitely a codec issue, and works well with VLC, only when the right codecs have been installed. Re-installing as the previous lame answer suggested, back in 2014, has zero effect. This is clearly a bug, or, at least there needs to be a 'Preference' option to change how the file is saved, more format options, etc.

Two years on and we are still looking for an answer...

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Paul Leonard (paul-leonard) said :

We have also tried the 'suggested' WEBM' setting, which, while does make the saved file smaller, still does not solve the main issue. As much as I personally hate Quicktime & WMP, Kazam files will not run on these platforms. We also tried different FMS rates.

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Dee Benbow (denben1) said :

This is marked answered, but the problem is still there. Is there any real solution? or is this a non issue to those in charge?

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Koen Roggemans (koen-roggemans) said :

I have the same problem. Screencasts with the H.264 codec in Kazam placed on the web seem to work only in Chrome, not in Firefox, Safari, Edge.

I noticed the codec it produces is H.264 (Constrained Baseline Profile)

I uploaded my files to and they come back with codec H.264 (High 4:4:4 Profile) and those files do work in all mentioned browsers.

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Tim Court (tctimmeh) said :

Is there an in-app solution to this problem yet? I just created an mp4 with the latest version of Kazam and got complaints that the file isn't viewable. It works in some players but not others, including VLC. Re-encoding to libx264 with Shotcut fixes the problem.

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