GeoVision GV-BL110D, Руководство пользователя, Страница: 189 / 393

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Note that for all the cameras (except GV-PTZ010D), the resolution options
available for sub stream vary with the resolution selected for its main
stream. For example, if a 4:3 resolution is selected for the main stream in
GV-BX320D-0, two options, 640 x 480 and 320 x 240 will be available for
its sub stream.
Most 3GPP mobile phone supports video streaming with MPEG4 video.
Due to the limitation of the bandwidth for 3GPP, only the resolution of
320 x 240 will be supported for mobile phone setting. For mobile phone
connection, see
Mobile Phone Connection, Chapter 17 .
[Bandwidth Management] When using H.264 or MPEG4 it is possible to
control the bitrate, which in turn allows the amount of bandwidth usage to
be controlled.
„
VBR (Variable Bitrate): The quality of the video stream is kept as
constant as possible at the cost of a varying bitrate. The bandwidth is
much more efficiently used than a comparable CBR.
Set the image quality to one of the 5 standards: Poor , Fair , Good ,
Great and Excellent .
Maximal Bit Rate: When the system bitrate exceeds the specified
Maximal Bit Rate, the system will automatically lower its bitrate so as
not to exceed it. Select one of the bitrates from the drop-down list or
select
Auto if you do not want to enable this function.
„
CBR (Constant Bitrate): CBR is used to achieve a specific bitrate by
varying the quality of the H.264 or MPEG4 stream. Select one of the
bitrates from the drop-down list.
[GOP Structure and Length] Set the maximum number of frames
between every key frame. The limit is 1 key frame for every 30 frames.