Why is it necessary that our mp4 video files are fully buffered when played in our video player? How do I know if the moov atom is placed at the end of the file? How do we correct that when encoding?

This issue occurs when you use Adobe's old-style progressive video download. Instead, use HTTP or RMTP streaming.

If it's necessary to continue using progressive video delivery, take the master (source) video and upload that to SPS. Providing it is a supported input format, SPS can make different video sizes depending on your defined setup, and uses a reliable codec and format.

You can find more information here:

Here is some info about moov atom (
“Unless specified otherwise, the moov atom is normally stored at the end of the file in on-demand content, after all of the information describing the file has been generated. Depending on the type of on demand delivery method selected—progressive download, streaming, or local playback—the location will need to move either to the end or to the beginning of the file.”

If the above two options don't work, you can use a tool called AtomicParsley ( to check where the moov atom of a file is:

Sample usage:
C:\Users\mavance\Desktop\AtomicParsley-win32-0.9.0>AtomicParsley myvideo.mp4 -T
Atom ftyp @ 0 of size: 32, ends @ 32
Atom free @ 32 of size: 8, ends @ 40
Atom mdat @ 40 of size: 28717284, ends @ 28717324
Atom moov @ 28717324 of size: 96541, ends @ 28813865

For information about moving the moov atom to the start of the file, see

This program helps you move the important meta info from the end to the beginning of the file. It helps the video to play back as early as possible:

When you run AtomicParsely again, you see that the moov atom has changed.
Upload the new video to SPS, publish, ensure that the cache is clear, and retest.

If there is still some issue, try using this alternative tool called MP4 FastStart (, which can also resolve this issue.

Dit werk is gelicentieerd onder de Creative Commons Naamsvermelding/Niet-commercieel/Gelijk delen 3.0 Unported-licentie  De voorwaarden van Creative Commons zijn niet van toepassing op Twitter™- en Facebook-berichten.

Juridische kennisgevingen   |   Online privacybeleid