Documentation for pdf 2.0 extension conforming to ISO32000-2:2020 Annex E. The main purpose of this extension is to annotate appearance intervals in videos of lectures showing slides on projector screen.
Created for application at https://github.com/DanValnicek/slide-video-sync for creating a list of intervals in video where a slide is being shown. This can be helpful to students trying to study wanting to know what was said about topic being shown on a given slide.
The extension entry iin the /Extensions dictionary looks something like this:
/Extensions <<
/Type /DeveloperExtensions
DANV <<
/BaseVersion /2.0
/ExtensionLevel 1
/URL (https\072\057\057github\056com\057DanValnicek\057pdf\055ext\055slide\055video\055sync)
>>
>>
Every page dictionary gets extended with /DANV_SlideVideoSync which is a key for a dictionary containing info produced by this extension.
An array with the key /SlideAppearanceIntervals which contains an array of arrays with 2 values.
The values in the the subarrays are in the form [ start end ] - start and end time in miliseconds at which the slide appears in the video.
<<
/Type /Page
/DANV_SlideVideoSync <<
/SlideAppearanceIntervals [ [ 119000 121000 ] [ 124000 124000 ] [ 127000 128000 ] ]
>>
>>
The slide in this example appeared 3 times in total in the video in non overlapping intervals.
- video information that these intervals were made for (e.g. video hash, video name, link for download)