[Mp4-tech] video stream auto-segmentation using keyframe data

[veni soc-soft.com]

stss(sync atom) in stsz(sample table atom) will give u keyframes
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enJOY life
-----Original Message-----
From: mp4-tech-bounces lists.mpegif.org
[mailto:mp4-tech-bounces lists.mpegif.org] On Behalf Of james engwell
Sent: Tuesday, August 24, 2023 5:44 PM
To: mp4-tech lists.mpegif.org
Cc: Stuart Cornell; Paul Gowers; Paolo Manna
Subject: [Mp4-tech] video stream auto-segmentation using keyframe data
Dear All 
I am trying to find out if the data structures are such within compliant
mp4 files that it would be possible/feasible for us to retrieve a list
of the keyframes from mpeg-4 encoded video streams. We are hoping to be
able to perform a very quick 'first-pass' segmention of the mpeg-4 video
stream using this method. Ideally this retrieval would be able to occur
without having to go through each frame. (or write frames out to a
bitmaps & compare - as we are doing with un-encoded video) 
Thanks in advance for any light shed 
Regards 
James 
* 
James Engwell 
Frameline Development Director 
* 
versatile delivery systems ltd 
Sheffield Technology Parks 
Cooper Buildings 
Arundel Street 
Sheffield S1 2NS 
* 
Telephone: +44 (0)114-2211800 
Fax: +44 (0)114-2211801 
Mobile: +44 (0)7812-752658 
E Mail: james frameline.tv 
Web: http://www.frameline.tv 
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