Technical Manual
© 2006-2010 by HIKVISION. All rights reserved.
21
Explanation:
To stop the sub-channel video capture
Return value:
0—success; -1 – failed;
4.2.29.
int SetIBPMode(int channelHandle, int KeyFrameIntervals, int BFrames, int PFrames, int
FrameRate);
Parameter:
int channelHandle channel handle
int KeyFrameIntervals key frame interval (default is 100)
int Bframes number of B frame (default is 2)
DS-42xx card does not support B frame
int Pframes number of P frame
int FrameRate frame ratio (default is 25)
Explanation:
To set frame structure, key frame interval, number of B frame and frame rate. The value of
key frame interval can be not less than 12 , number of B frame can be 0, 1,2 , number of P
frame is set invalid at present, the range of frame rate is from 1 to 25 , and these value can be
set during capturing ;
Note:
Explanation of key frame interval: Key Frame is the image frame, which is compressed
within fames in the encoding stream. Its characters are the good image definition while
needing big data capacity, and usually used as the original reference of frames interval
encoding. Key frame interval is the numbers of the frames between the continuous frames
encoding.
Return value:
0—success; -1 – failed;
4.2.30.
int SetDefaultQuant(int channelHandle, int IQuantVal, int PQuantVal, int BQuantVal);
Parameter
:
int channelHandle channel handle
int IquantVal I frame quantization parameters
int PquantVal P frame quantization parameters
int BQuantVal B frame quantization parameters
Explanation:
To set video encode quantization parameters. It is used in adjusting image quality, a simple
rule is that lower quantization will produce higher quality image, and its range is from 12 to
30. For example: 15, 15, 20 and 18, 18, 23. The default of system is 18, 18, 23; The normal
rules is the I frame and P frame is set as the same, while B frame is 3 to 5 bigger than them.
Note
:
Explanation of quantitative coefficient: quantitative coefficient is the parameter, which
greatly affects the encoding, image quality and bit rate under MPEG standard. The lower the
quantitative coefficient is, the better the quality and the higher the bit rate. On the contrary,
the worse the quality is and the lower the bit rate.