Which is the proper I-Frame distance used in 3rd party Software?
“GOP” (Group of Pictures) also known as “I-Frame distance“ is the I-Frame refreshment interval
Nowadays the Bosch encoders support long Fixed GOP lengths , up to 250.
Some 3rd party management software like e.g. “Genetec” or “Cathexis” etc. can set these large GOP lengths ones these get assigned to the management system.
But also, of course, through the Bosch interface this can be configured.
When dealing with 3rd party or VSG, it’s recommended to get at-least "1" I-frame every second (normal scene).
What Is the concern?
With large GOP lengths the image quality potentially can suffer and degrade dramatically due to lag of I-Frames specially when the camera frame rate (encoder interval) is also set low.
When you only look to static scenes large GOP lengths could be useful.
But for dynamic scenes or with the usage of Autodome cameras it recommended to use a GOP30 or better.
Rule of thumb set the GOP length equal to the frame-rate, this result in "1" I-frame every second
Example of bad config:
* Camera encoding interval is 10fps
* IP-GOP 250 (means you will receive each time a new I-frame after 249 P-frames (IP-GOP structure).
* so I receive an I-frame 250/10=every 25sec (0.04-frame per sec)