Vivotek ND9323P - Page 86

VIVOTEK - Built with Reliability
86 - User's Manual
■ Dynamic Intra frame period
High quality motion codecs, such as H.265, utilize the redundancies between video frames to deliver
video streams at a balance of quality and bit rate.
The encoding parameters are summarized and illustrated below. The I-frames are completely self-
referential and they are largest in size. The P-frames are predicted frames. The encoder refers to the
previous I- or P-frames for redundant image information.
P I P P P P P P P P P P P P P P P P P P P I
P I P P P P P P P I P P P P P P P I
Static scene
Activities
P P P
P I P P P P P P P I P P P P P P P I
By dynamically prolonging the intervals for I-frames insertion to up to 10 seconds, the bit rates
required for streaming a video can be tremendously reduced. When streaming a video of a
static scene, the Dynamic Intra frame feature can save up to 53% of bandwidth. The amount of
bandwidth thus saved is also determined by the activities in the eld of view. If activities occur
in the scene, rmware automatically shortens the I-frame insertion intervals in order to maintain
image quality. In the low light or night conditions, the sizes of P-frames tend to be enlarged due
to the noises, and hence the bandwidth saving e󰀨ect is also reduced.
Streaming a typical 2MP scene normally requires 3~4Mb/s of bandwidth. With the Dynamic Intra
frame function, the bandwidth for streaming a medium-tra󰀩c scene can be reduced to 2~3Mb/s,
and during the no-tra󰀩c period of time, down to 500kb/s.
H.264/265 Frame Types
Dynamic Intra Frame w/
static scenes
Dynamic Intra Frame w/
activities in scenes