Video API Extensions legacy

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This is a legacy page. The information bellow is not compatible with Elphel 393 or 353/363 series cameras.

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The current implementation of the Video API has a number of features which are absent from the standard Axis Video API.

Enabling extensions

By default the Video API extensions are blocked. To unblock them it is necessary to set a corresponding variable:

Obtaining static and dynamic images

The standard interface for obtaining static and dynamic images in JPEG and MJPG formats has a few additional parameters.

e_dcm_hor - horizontal decimation (resolution/image size reduction)
e_dcm_vert - vertical decimation (resolution/image size reduction)
e_bin_hor - horizontal binning (sensitivity for lower resolution)
e_bin_vert - vertical binning (sensitivity for lower resolution)
e_woi_width - sensor active window width (before decimation)
e_woi_height - sensor active window height (before decimation)
e_woi_left - sensor active window left margin (before decimation)
e_woi_top - sensor active window top margin (before decimation)
e_virt_width - virtual frame width
e_virt_height - virtual frame height
e_fliph - flip (mirror) image horizontally (uses in-sensor capabilities)
e_flipv - flip (mirror) image vertically (uses in-sensor capabilities)
e_exp_time - exposure time (0.1 msec step)
e_gamma - gamma correction value (%)
e_pixel_low - black level
e_pixel_high - white level
e_saturation_blue - color Saturation (%), Blue
e_saturation_red - color Saturation (%), Red
e_gain_r - analog gain RED (or mono)
e_gain_g - analog gain GREEN (or green in "red" line)
e_gain_b - analog gain BLUE
e_gain_gb - analog gain GREEN in "blue" line)
e_spec_kac_gga - Kodak KAC1310 analog gain Y (all colors)
e_spec_kac_ggb - Kodak KAC1310 analog gain ? (all colors)
e_spec_kac_ggm - Kodak KAC1310 mode


Example of obtaining a static image - use the following parameters:

Example of obtaining a dynamic image (MPJPG) - use the following parameters:

You can play this videostream, for example, by using MPlayer (for a more detailed description see Using Mplayer With Video API):

$mplayer -demuxer lavf ""

If any of the parameters are not specified, the default values are used. You can find these values at the address:

Note: All API extensions have the prefix "E_".

You can change the default value in the standard way for the Axis Video API. For example:

Obtaining information about the system status and default values

To obtain information about the system status variable you must use the following path:

In an addition to the standard "rfc" format there is also the possibility to use XML format. You must use the responseformat parameter for this. For example:

Note. If the responseformat is not specified or specified incorrectly, the default value of "rfc" will be used.

Video streaming: RTP/MJPG and RTP/Theora

The Elphel cameras can transfer the video stream by RTP protocol.



Exposure control

The Elphel cameras support the standard and advanced exposure control interface. For the standard settings see Video_API

To enable autoexposure it is necessary to use the following command:

Enabling the manual control of exposure:

Obtaining the exposure state:

Window settings:

Exposure max.values: