User manual
ARECONT VISION USER MANUAL 56
Arecont Vision 425 E Colorado St, 7
th
Floor Glendale, CA 91205 8/1/2012
www.arecontvision.com
X0, Y0, X1, Y1 are the left, top, right and bottom coordinates of the requested image window,
respectively. These values cannot exceed the size of the image sensor array for the specific camera
model and should be divisible by 32 if Res = full and 64 if Res = half.
QP is the quantization parameter for H.264 encoder. To achieve a higher quality image, a lower QP is
needed. Recommended values are in the range (16..37);
Doublescan is the parameter that allows the user to specify whether the camera should delay the
frame output until a new frame is available from the sensor (doublescan = 0) or the request should be
serviced by outputting the content of the memory buffer that has been already once output
(doublescan=1, useful for picture-in-picture display).
SSN specifies stream identifier. MPEG codecs including H.264 codecs are context dependent
(decoding of the current frame depends on the previous frame(s)). The stream is a sequence of
frames of the same resolution which can be decoded sequentially by one instance of an MPEG
decoder. Accordingly, SSN is a means to distinguish different streams from one another. Use a
unique SSN for each stream with a unique image size, quality and/or frame rate. Each camera
supports up to eight
simultaneous non-identical streams. Each client must have a unique (ip:ssn)
Iframe set to 1 will force the camera to return an Intra frame with a corresponding SPS and PPS as
an IDR slice, so that the stream is decodable from this point. When opening a new stream (for
example when changing the image size and/or frame rate) the Intra frame will be sent automatically
regardless of the input value of iframe. To reduce the stream size, reduce the frequency of iframe =
1 in the requests. The default number of P-frames for any of the streams sent by the camera is set
using HTTP command :
http://camera/setreg?page=3®=21&val=(number of P-frames)
The camera will return an Intra frame even if iframe in the request is set to 0 when the on-camera
counter of P-frames fills up. To find out whether an Intra frame was received, check the HTTP
Content Type.
Bitrate is used to set up a constant bitrate of the H.264 stream in kilobits per second. If this parameter
is present in the request string and is larger than zero then the QP parameter is ignored, and the
camera adjusts quantization parameters automatically to maintain the specified bitrate.
Intra_period is valid only in bitrate control when a non-zero bitrate is present in the request string and
iframe=1 is periodically requested by the user. In this case, the user must specify the intra-frame
period at which the user is sending requests with iframe=1. If the user does not specify
intra_period
in this case, then bitrate control will not function correctly unless the actual period of sending
iframe=1 requests is the same as the default number of P-frames specified in register 3:21 of the
camera via