Can I adjust the "moov atom" when producing a video?

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We are using an external vendor to host the videos we produce in order to embed them on websites and a LMS. In reviewing the source file specifications for the upload, I came across this:

Make sure your source file is created with the 'moov atom' at the front of the file. The 'moov atom', also known as 'movie atom' or 'QT Fast Start', contains information about the video file. This needs to be at the beginning of the file in order to ensure fast transcoding.

Unless otherwise specified, most encoding software will put the moov atom at the end of the file. Look for one of these settings in your encoding software to override the default and place the atom at the beginning: "progressive download," "fast start," "use streaming mode," or similar options.

Is there a setting in Camtasia Studio 8 I can adjust to accomplish this? We are experiencing some bitrate/buffering issues and I'm wondering if this may be part of the problem. Thanks for any insight you can provide!
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Courtney Wozetek

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Posted 5 years ago

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Fred Grover, Champion

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Courtney that is a great question and I cannot answer that but if you are looking for a quicker answer I would contact TechSmith and ask them about this and see if there is an option or a work-a-round to do what you want. I have provided the contact information below for you.

TechSmith Support Information

http://support.techsmith.com/


Phone: +1.517.381.2300
Toll Free: 800.517.3001
(U.S. & Canada Only)
8:00 AM to 7:00 PM EST Monday through Friday

Post back and let us know what you find out for others who may want to know if it can be done. Thanks.

Possibly a TechSmith Employee will jump in here and answer that question for us too. When it comes to technical issues like that I leave it up to the people who program the software and know it the best. Unless another user(s) have asked this question before and have already received an answer and post it back here I cannot say as that is something I leave for the Pros.

Thanks for posting and have a great day/night.
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Courtney Wozetek

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Thanks Fred! I will follow up with support directly, but if anyone else has come across this, I'd welcome their input!
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Jennifer Bedford, Official Rep

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Thanks Courtney.  Once you chat with support, it would be great if you could post the response here for anyone else to see.
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Kevin Mojek, Employee

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There is no setting exposed but yes, we do re-order the produced-out MP4 file so that the MOOV atom precedes the MDAT content.
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Courtney Wozetek

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This is what I heard back from Support:
When producing to MP4 in Camtasia the MOOV atom should always be at the beginning.

I will continue to explore other reasons why we may be experiencing issues (likely on the end of the host and not the export from Camtasia). Thanks!
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Fred Grover, Champion

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Jennifer and Kevin would it be possible to make a short video showing how and what needs to be done to get this correct for the users? Thanks and let us know.

Courtney thank you for posting back what you found out and let us know if that works for you or not. Have a great day/night.
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Kevin Mojek, Employee

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There's nothing to show really... it's just a hidden step that's built into the MP4 production code. There are two main parts to an MP4 file... the "movie data" or MDAT part contains all the raw data required to reconstruct the compressed video and audio; This normally is most of the file content. After encoding is complete, that is followed by a "movie" atom which tells how to interpret the MDAT data: timing and sizes of each individual sample, etc. This information is needed upfront in order to decode the file. If you're playing the file back locally, it doesn't matter too much what order these are in since disk access is usually fast. For streaming though, if the MOOV data was left at the end of the file, it would be necessary to download nearly the entire file before playback could start. So, it's pretty common to swap the order of these two parts and that's all that we're doing here. Even if the file were intended solely for local playback, there's no harm in reordering, so we don't expose it as a production option.

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