ACTi V11 User Manual
Page 47
Encoder Firmware User
’s Manual H1.02.30
this mode compared to Variable Bit Rate mode.
Under
Variable Bit Rate
mode (VBR), the device will keep the video
quality stable while the bit rate may occasionally go up or down,
depending on the complexity of the scene.
Video Max Bit Rate
(only for H.264)
Defines the upper limit of the bitrate (only available under CBR
mode). The bitrate will be floating slightly under that limit. For
example, if the limit is set as 2M, the bitrate will be floating around
1.6~2.0 Mbps.
If the Video Max Bit Rate is chosen
as
Unlimited
, then the
Video Bit
Rate
selection box will appear that
defines the bit rate level.
Video Bit Rate
(only for H.264)
Under CBR mode, when
Video Max Bit Rate
is chosen
Unlimited
,
the user can define the AVERAGE bit rate. For example, if the
Video
Bit Rate
is chosen
2M
, then occasionally, the actual bit rate may go
below or beyond 2M, but in the long run, the average bit rate will be
very close to 2M. This mode allows the most accurate storage
estimations, however, while planning the bandwidth, please consider
the occasional peaks of bit rate.
Quality
H.264 Compression:
Under VBR mode, the bit rate will
be floating while the video quality
will be stable and follows the quality
standard set by the user. The user
can choose either
High
,
Medium
or
Low
quality. The higher is the
quality level, the more bit rate the device will use to achieve the target
quality.
MJPEG Compression:
The user can define the quality with the numeric scale from 1 to 100.
The default MJPEG quality is 60. The higher is the quality level, the
more bit rate the device will use to achieve the target quality.
GOP 1 I-frame
(only for H.264)
Under VBR mode it is possible to adjust the GOP length - that is the
occurrence rate of I-frames. By default, there is one I-frame per
second. For example, in case of 30fps, there will be 1 I-frame and 29
P-frames every second by default. When the GOP is changed to
“1
I-frame per 5 seconds
”, then there will be one I-frame, followed by 149
P-frames. In case of the static scenes, long GOP can further minimize
the bandwidth and storage consumption.
After changing any of the items above, click
Apply
to save the changes. The
Reset
button
undoes the changes that had just been made but not applied yet.