Long GoP structure

Problem Description

Video sequences comprise a series of "Groups of Pictures" (GoP), each with an I frame and some number of P and B frames.  The number of B and P frames can range from 0 to several hundred.  When packet loss events occur, they will impact video quality for the remainder of the GoP until "reset" by the next I frame.

A short GoP sequence will provide better performance on connections with packet loss and may result in shorter channel change times, but will use more bandwidth.  A long GoP sequence will take less bandwidth but will be less tolerant of packet loss and may increase channel change delay.


Periods of degraded quality lasting for a noticeable period of time may result from long GoP structures extending the effect of packet loss events.

Excessive channel change delays can also be the result of long GoP structures.


Use a shorter GoP structure or consider the use of retransmission or forward error correction to "repair" losses.


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