Digital Watchdog DWC-MV72Wi28TW User Manual page 17

Setup - Video & Audio Setup
Video Configuration
6
7
8
GOP(Group of Pictures) Size - Set up the number of frames (P-frame) which contain only changed information
6
based on the basic frame (I-frame). Regarding videos with lots of movement, if you set GOP size bigger, only
the number of P-frames is bigger.
As a result, the video resolution will be low but 'File size' and 'Bit-rate can be decreased.
GOP(Group of Pictures) Size -
I-frame and P-frame creation for MPEG4, H.264, and H.265 (HEVC) video compression. 'I-frame', also known
as 'key-frame', refers to the complete image data for a specific video frame. 'P-frame' refers to the changes
in the image in comparison to the previous video frame. As a result, the GOP consists of one I-frame and
several P-frames. For improved video quality, use a lower number of P-frames for this setting.
Profile - The profile defines the subset of bitstream features in H.264, H.265 (HEVC) stream, including color
7
reproduction and additional video compression.
H.264: Main, High / H.265 (HEVC): Main
Main - An intermediate profile with a medium compression ratio. Supports I-frames, P-frames, and B-frames.
High - A complex profile with a high compression ratio. Supports I-frames, P-frames, and B-frames.
Bitrate Mode - Select the bit rate control scheme of video compression from CBR (Constant Bit Rate) or VBR
8
(Variable Bit Rate).
CBR - To guarantee the designated constant bit rate, the quality of the video is controlled in this
mode. Therefore, the quality of the video is likely to be varying when network traffic is changing.
VBR - To guarantee the designated quality, the bit rate of the video stream is changed in this mode.
Therefore, the frame rate of the video is likely to be varying when network traffic is changing.
This category will not appear if you select the codec.
17