HIKVISION DS-8004HCI-S User Manual page 98

Note: If you change this option, the DVR must reboot before the changes take effect.
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Resolution: Higher resolution provides a clearer image. The resolution options from low
to high are: QCIF, CIF, 2CIF, DCIF, 4CIF.
Note: Different DVR may support the different resolution level, some supports up to 4CIF and
some may only support up to CIF. Please find the real resolutions under this list box of a particular
DVR. If you change resolution options the DVR must reboot before the changes take effect.
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Bit Rate: You can select different bit rates to accommodate different settings of
resolution and frame-rate options include: (bps): 32K, 48K, 64K, 80K, 96K, 128K, 160K,
192K, 224K, 256K, 320K, 384K, 448K, 512K, 640K, 768K, 896K, 1M, 1.25M, 1.5M,
1.75M, 2M and "User define".
The appropriate max bit rate selection is related to the resolution selected. If you select a
high resolution, you must select high bit rate. For CIF resolution, the typical max bit rate
is 384K~768Kbps for real time compression. For 2CIF/DCIF resolution, the typical bit
rate is 512K~1Mbps real time compression. For 4CIF resolution, the typical bit rate is
1.25Mbps~1.75Mbps for real time compression. Of course, you will select the proper bit
rate based on the camera, background and image quality requirement.
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Frame Rate: Frame per second. Options are: Full (NTSC is 30 FPS and PAL is 25FPS),
20, 16, 12, 10, 8, 6, 4, 2, 1, 1/2, 1/4, 1/8, 1/16. For lower frame rates you can select low
bit rates to save bandwidth.
Note: Some series DVR may have lower frame rate for a particular resolution.
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PreRecord Time: This sets the buffer size for retaining video/audio when you enable
motion detection recording or external alarm recording. You can define a prerecord time.
The options are: No Prerecord, 5 Seconds (default selection), 10 Seconds, 15 Seconds, 20
Seconds, 25 Seconds, 30 Seconds and Max Prerecord. MaxPreRecord is to save all data
in Prerecord buffer. The Prerecord time is related to the bit rate (the lower the bit rate, the
longer the Prerecord time).
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If the bit rate (Max bit rate) is very low, and you select the "Prerecord Time" as "5
Seconds" the actual prerecord time is more than 5 seconds. On the other side, if the bit
rate is high, and the "Prerecord Time" is set to "30 Seconds," the actual prerecord time
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