dallmeier DF4910HD-DN - Page 65

DF4910HD-DN | DDF4910HDV-DN-IM/-SM
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3D noise lter (spatial + temporal)
This function can improve the image quality by noise reduction and therefore enhance the
compression performance.
Note that this function is not effective with resolutions higher than 720p.
• Compares pixels both within and between frames
• Very effective noise suppression
• May cause high CPU load and therefore may slow down the encoding speed and lead
to a loss of frames
• May blur moving objects
• May cause a loss of detail
Frames/Second
The frame rate (value in fps) denes the number of consecutive frames produced per
second.
The higher the frame rate, the smoother the video playback.
However, a higher frame rate also requires a higher bandwidth usage (transmission ca-
pacity) and more hard disk storage space for the recording of video material.
25 (“PAL countries”) or 30 fps (“NTSC countries”) meet the requirements for real-time ap-
plications.
Bitrate
The bit rate refers to the number of bits per second used to encode the video.
The more bits are used to represent the video data per second, the higher the quality is.
However, a higher bit rate also requires a higher bandwidth usage (transmission capacity)
and more hard disk storage space for the recording of video material.
Low bit rate High image compression
Small data volume
Poor image quality
Low bandwidth and hard disk space usage
High bit rate Low image compression
Large data volume
High image quality
High bandwidth and hard disk space usage
Usually, most requirements in surveillance applications are met with a bit rate between 4
and 6 Mbps.