2N SELEA iZero, User Manual

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COMPRESSION PARAMETERS

Video
iZero 

manages 2 different streaming video profiles, which can be independently configured. The first profile refers to the video 

stream captured by the built-in high speed sensor, the second one still to the number plate sensor but configured differently. 

The parameters that can be changed are the same for each profile, although their values will depend on the actual profile.

Resolution:

 to select the size of the supplied 

image.

Coding:

it allows to select the type of 

compression applied to the video 

stream for each profile.

MPEG4 (default):

 the video stream 

is transmitted with less bandwidth.

H264:

 the video stream is of 

high quality and, thanks to its 

compression, is transmitted with a 

lower bandwidth.

Quality:

allows you to select the quality of 

the images displayed with each 

profile from five levels.

Higher quality will entail higher band requirements and higher snapshot kb size. This may cause delays in 

transferring the images (depending on network and network traffic) and in uploading them to the hard-disks.

Coding control:

it gives the possibility of specifying which parameters should be kept constant in case of network 

performance variations.

Band: 

in case of network channel quality decrease, the number of frames sent will automatically be reduced, 

although they will be of the quality selected by the user.

Intra rate: 

only for MPEG4 coding, it indicates the interval at which intra-frames are included in the video stream. 

Video streams compressed using the MPEG4 standard consist of two types of frames: intra-frame and 

p-frame. “Intra” frames contain a complete image, similar to a JPEG, and are also called “key frames”. “P” 

or “predicted” frames do not contain a complete image, but only information regarding the differences 

between the current frame and the previous key frame. If subsequent frames are very similar to each 

other, this technique allows to reduce band usage whilst maintaining good image quality. It is however 

necessary to update the key frame at regular intervals, by including an intra-frame in the stream. The 

“Intra-Rate” field can be used to indicate every how many frames an intra-frame must be included. The 

more the distance between intra-frames, the more video stream compression will be possible, at least 

in almost static captures. However, it must be considered that when playing back a recorded video, the 

cursor may only be placed near key frames. Therefore, excessive distance between intra-rate frames may 

not be appropriate. An “Intra-Rate” of 100 is normally a good compromise.

Stream M-JPEG quality: 

  changes the quality of the image you see by watching the live image via the browser

Snapshot JPEG quality: 

  changes the quality of the snapshot that you can ask the camera for via HTTP command:

http://<IP_camera>/P<n>.jpeg

, where n=profile number (1,2 or three for the context where 

provided)

The HTTP call for the snapshot request can be made by a third-party software or simply by typing 

the command in the browser's address bar.