<p>The Media Atom object does not have a Flags field, but the <a href="https://developer.apple.com/library/mac/documentation/QuickTime/qtff/QTFFChap2/qtff2.html#//apple_ref/doc/uid/TP40000939-CH204-32999" rel="nofollow">Media Header Atoms</a> does:</p>

<blockquote>
  <p>Flags - Three bytes of space for future movie header flags.</p>
</blockquote>

<p>In which case it's basically say, these values are reserved for future use, and presently are just byte alignment packing.</p>

<p>In most RFC's these area's are called Reserved as compared to flags.</p>

<p>This would explain why they are zero, as by the spec, they should be set zero, so in the future none zero value can be interpreted to mean "something".</p>

<p>If I'm mistaken the section you refering let me know.</p>

CC BY-SA 3.0
2014-06-24T04:19:29.927Z
2014-06-24T04:19:29.927Z
Simeon Pilgrim
<p>They are a type of metadata specific to the QuickTime container.
They can contain all kinds of extra information for the video player to read out and use.</p>

<blockquote>
  <p>QuickTime movie atoms have an atom type of 'moov'. These atoms act as
  a container for the information that describes a movie’s data. This
  information, or metadata, is stored in a number of different types of
  atoms. Generally speaking, only metadata is stored in a movie atom.
  Sample data for the movie, such as audio or video samples, are
  referenced in the movie atom, but are not contained in it.</p>
</blockquote>

CC BY-SA 3.0
2014-06-23T17:25:30.183Z
2014-06-23T17:25:30.183Z
timonsku
<p>What is the purpose of Media Atom 'flags' within the QuickTime videos, I see for the most part they are set to zero but what does this achieve?</p>

<p>Documentation I am reading is the following: <a href="https://developer.apple.com/library/mac/documentation/QuickTime/qtff/QTFFChap2/qtff2.html" rel="nofollow">https://developer.apple.com/library/mac/documentation/QuickTime/qtff/QTFFChap2/qtff2.html</a></p>

<video><mp4><quicktime>
QuickTime File Format (Atoms & Flags)
user6100
# QuickTime File Format (Atoms & Flags)

(Asked by: username_0 on 2014-06-23)

What is the purpose of Media Atom 'flags' within the QuickTime videos, I see for the most part they are set to zero but what does this achieve?

Documentation I am reading is the following: <https://developer.apple.com/library/mac/documentation/QuickTime/qtff/QTFFChap2/qtff2.html>

**Tags:** video, mp4, quicktime


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## 2 answers

### Answer by username_1 on 2014-06-24. Score: 2

The Media Atom object does not have a Flags field, but the [Media Header Atoms](https://developer.apple.com/library/mac/documentation/QuickTime/qtff/QTFFChap2/qtff2.html#//apple_ref/doc/uid/TP40000939-CH204-32999) does:

> Flags - Three bytes of space for future movie header flags.

In which case it's basically say, these values are reserved for future use, and presently are just byte alignment packing.

In most RFC's these area's are called Reserved as compared to flags.

This would explain why they are zero, as by the spec, they should be set zero, so in the future none zero value can be interpreted to mean "something".

If I'm mistaken the section you refering let me know.


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### Answer by username_2 on 2014-06-23. Score: 2

They are a type of metadata specific to the QuickTime container.
They can contain all kinds of extra information for the video player to read out and use.

> QuickTime movie atoms have an atom type of 'moov'. These atoms act as
> a container for the information that describes a movie’s data. This
> information, or metadata, is stored in a number of different types of
> atoms. Generally speaking, only metadata is stored in a movie atom.
> Sample data for the movie, such as audio or video samples, are
> referenced in the movie atom, but are not contained in it.


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