FLIR D-Series C Installation Manual page 54

3 Advanced Configuration
Settings
The parameters in the Settings section will have a significant impact on the quality and bandwidth
requirements of the video stream. In general it is recommended that the default values are used
initially, and then individual parameters can be modified and tested incrementally to determine if the
bandwidth and quality requirements are met. The proper settings for a given installation will depend
on many factors, including the network capabilities, the processing power in the camera as well as the
client computer, the scene contrast, and personal preferences. When the installer is faced with
limitations (such as restricted bandwidth due to a wireless network link), it will be necessary to
compromise image size, frame rate, and/or image quality in order to achieve an acceptable video
stream.
For each video stream, the Codec Type
options are MPEG4, H.264 or MJPEG. MPEG4
requires the least amount of processing, and
MJPEG requires the most. See section
"MJPEG Codec Type" on page 3-15 for
additional notes on the MJPEG type, which is
used by the Live Video stream
The Bit Rate parameter is only used when the
Rate Control parameter is set to CBR (Constant
Bit Rate). With the CBR setting, the system
attempts to keep the resulting bit rate of the
video at or near the target bit rate.
By default, the Rate Control parameter is set to
CVBR (constrained variable bitrate) for MPEG4
and H.264 streams. The VBR (variable bit rate)
option attempts to maintain a specified quality at
a constant level by varying the bit rate
depending on the scene content. The CBR
(constant bit rate) option uses a best effort
attempt to adhere to the Bit Rate setting; with
high contrast/detail scenes, the quality may be compromised due to the bit rate limitation. With the
CVBR option, the stream may exceed the bitrate momentarily while attempting the maintain the
quality level.
The Quality parameter works in cooperation with the Rate Control. The quality setting (Low, Medium
or High; default: High) provides a relative way to balance video quality, latency and bandwidth. When
set to High, the video image will be high quality with high bandwidth and the possibility of some
latency since the encoder may take longer to compress the video.
The I-Frame Interval parameter controls the number of P-frames used between I-frames. I-frames
are full frames of video and the P-frames contain the changes that occurred since the last I-frame. A
smaller I-Frame Interval results in higher bandwidth (more full frames sent) and better video quality. A
higher I-Frame Interval number means fewer I-frames are sent and therefore results in lower
bandwidth and possibly lower quality.
The Image Size parameter controls the video resolution size and therefore can have a considerable
impact on bandwidth usage. The larger the size of the frame, the better the resolution and the larger
the network bandwidth required. The following table provides the corresponding resolution for each
Image Size setting (note, some settings are not available on all cameras).
3-14 427-9030-01-12 Rev 130 Mar 2014