Video API Extensions legacy
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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.
Contents
Enabling extensions
By default the Video API extensions are blocked. To unblock them it is necessary to set a corresponding variable:
http://192.168.0.9/axis-cgi/admin/param.cgi?action=update&ElphelExtensions.Enabled=yes
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 |
Examples
Example of obtaining a static image - use the following parameters:
http://192.168.0.9/axis-cgi/jpg/image.cgi?e_dcm_hor=2&e_dcm_vert=2&e_woi_width=1000&e_woi_height=900&e_woi_left=600
Example of obtaining a dynamic image (MPJPG) - use the following parameters:
http://192.168.0.9/axis-cgi/mjpg/video.cgi?e_dcm_hor=2&e_dcm_vert=2&e_woi_width=1000&e_woi_height=900&e_woi_left=600
You can play this videostream, for example, by using MPlayer (for a more detailed description see Using Mplayer With Video API):
$mplayer -demuxer lavf "http://192.168.0.9/axis-cgi/mjpg/video.cgi?e_dcm_hor=2&e_dcm_vert=2&e_woi_width=1000&e_woi_height=900&e_woi_left=600&bogus.mjpg"
If any of the parameters are not specified, the default values are used. You can find these values at the address:
http://192.168.0.9/axis-cgi/admin/param.cgi?action=list&group=ImageSource.I0.Sensor
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:
http://192.168.0.9/axis-cgi/admin/param.cgi?action=update&ImageSource.I0.Sensor.E_DcmHor=1
Obtaining information about the system status and default values
To obtain information about the system status variable you must use the following path:
http://192.168.0.9/axis-cgi/admin/param.cgi?action=list&group=ImageSource.I0.E_CurrentState
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:
http://192.168.0.9/axis-cgi/admin/param.cgi?action=list&group=ImageSource.I0.E_CurrentState&responseformat=xml
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.
RTP/MJPG
RTP/Theora
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:
http://192.168.0.9/axis-cgi/admin/param.cgi?action=update&ImageSource.I0.Sensor.Exposure=auto
Enabling the manual control of exposure:
http://192.168.0.9/axis-cgi/admin/param.cgi?action=update&ImageSource.I0.Sensor.Exposure=manual
Obtaining the exposure state:
http://192.168.0.9/axis-cgi/admin/param.cgi?action=list&group=ImageSource.I0.E_CurrentState.E_Exposure
Window settings:
http://192.168.0.9/axis-cgi/admin/param.cgi?action=update&ImageSource.I0.Sensor.E_Exposure.WinWidth=30&ImageSource.I0.Sensor.E_Exposure.WinHeight=45&ImageSource.I0.Sensor.E_Exposure.WinLeft=10&ImageSource.I0.Sensor.E_Exposure.WinTop=20
Exposure max.values:
http://192.168.0.9/axis-cgi/admin/param.cgi?action=update&ImageSource.I0.Sensor.MaxExposureTime=3000&ImageSource.I0.Sensor.E_Exposure.OverMax=30