48 | HDZ Series IP PTZ User Manual
Setting the GOV Length
The GOV length of an H.264 stream is the sum total of I-frames and P-frames in a GOV (Group
of video images). An I-frame, or intra frame, is an image that is coded in its entirety. A P-frame,
or predictive inter frame, refers to parts of earlier images (I-frames and/or P-frames) to code the
frame and therefore uses less bits to transmit the image. Increasing the GOV length decreases
the frequency of I-frames, and therefore reduces bandwidth consumption and image quality.
Setting the H.264 Profile
Use this setting to set each H.264 profile to one of either Baseline profile, Main profile or High
profile, according to its compression needs. With the same bit rate, the higher the compression
ratio, the better the image quality will be. To set the H.264 profile:
Under Video Rotate Type, select one of the following options from the drop-down list:
Normal. Video is not rotated or reflected (default setting).
Flip video. Video is reflected horizontally.
Mirror video. Video is reflected vertically.
90 degree clockwise. Video is rotated one quarter turn clockwise.
180 degree clockwise. Video is rotated one half turn.
90 degree counterclockwise. Video is rotated one quarter turn counterclockwise.
Click the Save button directly below the Video Rotate Type drop-down list.
Click the Streaming tab (Video Format is selected in lefthand column).
Under GOV Settings, type a value in the H.264-1 GOV Length field and/or the H.264-2
GOV Length field and/or the H.264-3 GOV Length field and/or the H.264-4 GOV Length
Enter a GOV Length value in the range from 2 to 64. The default value is 60
(NTSC), or 50 (PAL) for H.264-1 and -2, and 30 fps (25 fps PAL) for H.264-3 and
-4. The default value of 30 is a mid-level setting, which slightly reduces the
bandwidth consumption and also maintains relatively high image quality.
Decrease this value if you require higher quality images, and bandwidth
consumption is not an important consideration. Increase this value if you need to
reduce bandwidth consumption.
Click the Save button directly below the GOV Settings options.
Click the Streaming tab (Video Format is selected by default in the lefthand column).