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Use of Dynamic Layers when Switching between Layers

There are two different video frame structures used in the encoding profiles:

• Dynamic - frequent key frames, as needed

• Static - key frames every 2 seconds

The ABR algorithm will select a dynamic layer when switching between bitrates so the viewer will get a new key frame faster. The algorithm aggregates any requests; if any viewer needs a key frame, it makes key frame (up to one every half second). This guarantees that the viewer will be able to render the content from the new bitrate faster.

The algorithm knows when a key frame is coming up in the analogous static layer and switches the viewer to the static layer at the next key frame opportunity.