IPCam RT Trig.book
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Basler IP Cameras
Real-Time Trigger
APPLICATION NOTES
Document Number: AW000991
Version: 01 Language: 000 (English)
Release Date: 18 March 2011
Contacting Basler Support Worldwide
Europe and the Middle East:
Basler AG
An der Strusbek 60 - 62
22926 Ahrensburg
Germany
Phone: +49-4102-463-303
Fax: +49-4102-463-599
Email: bc.support.ip.emea@baslerweb.com
The Americas:
Basler, Inc.
855 Springdale Drive, Suite 203
Exton, PA 19341
U.S.A.
Phone: +1-610-280-0171
Fax: +1-610-280-7608
Email: bc.support.ip.usa@baslerweb.com
Asia:
Basler Asia Pte. Ltd
8 Boon Lay Way
# 03 - 03 Tradehub 21
Singapore 609964
Phone: +65-6425-0472
Fax: +65-6425-0473
Email: bc.support.ip.asia@baslerweb.com
www.basler-ipcam.com
All material in this publication is subject to change without notice and is copyright
Basler Vision Technologies.
Table of Contents
Table of Contents
1 Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1
2 Using Real-Time Triggering . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7
2.1
2.4
Enabling Real-Time Triggering . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7
Enabling Triggering Using the Web Client . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7
Enabling Triggering Using the Camera API . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7
Real-Time Triggering’s Impact on Streams . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9
Considerations When Using the Web Client. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9
Considerations When Using the Camera API. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9
Real-Time Triggering and Alarms . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10
Setting the Alarm Functionality Using the Web Client . . . . . . . . . . . . . . . . . . . . . . 10
Setting the Alarm Functionality Using the Camera API . . . . . . . . . . . . . . . . . . . . . 12
Minimum Time Between Trigger Signals . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14
2.5
Accessing a Stream Set for "JPEG (triggered)" Encoding . . . . . . . . . . . . . . . . . . . . . . 16
2.2
2.3
Revision History . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17
Application Notes
i
Table of Contents
ii
Application Notes
IP Camera Real-Time Trigger
1 Introduction
Basler IP cameras normally capture images without the need for any type of triggering by the user.
For instance, if a camera is set for a frame rate of 30 frames (images) per second, it will internally
generate all of the required signals needed to initiate the start of an image capture every 1/30th of
a second. In this scenario, the user has no control over when the start of any image capture will
occur. The camera simple begins each image capture as required to maintain the frame rate.
In many typical surveillance situations, this mode of operation is exactly what the user wants. An
automatically captured, continuous stream of images will be perfect, for example, to monitor the
actions on a banking floor or a building lobby. In some situations, however, it would be desirable to
be able to trigger an image capture at a particular point in time. For example, in a traffic control
situation the user might want to trigger an image capture at a particular point in time after a car
passes a sensor on a highway.
The real-time trigger feature on the camera guarantees that an image capture will start (i.e., the
exposure of an image will start) after a trigger signal is applied to a properly configured I/O port on
the camera and an "abort time" period has expired. For example, if the abort time for the camera
model you are working with is seven milliseconds, an image capture is guaranteed to start seven
milliseconds after a real-time trigger signal is applied to a properly configured port on the camera.
Note that the abort time may vary between camera models. Check the camera user’s manual to
determine the abort time for the camera model you are using.
Application Notes
1
IP Camera Real-Time Trigger
Figure 1, illustrates the normal image capture process used by the camera. In Figure 1, each blue
and yellow bar represents an image capture that is triggered by the camera’s internal triggering
process. The blue portion of each bar represents the time that the sensor is exposed to light during
an image capture. The yellow portion of each bar represents the time it takes for the camera to read
the image data out of the sensor once exposure is complete. At the end of the readout time, the
captured image is transmitted by the camera.
Figure 1 assumes that the camera is set to capture images at a rate of 30 frames per second (fps).
This means that the camera will trigger the start of a new capture every 1/30th of a second. Since
the camera is triggering these captures internally, a user has no way of knowing exactly when any
of the image captures will start.
You may notice in Figure 1 that the exposure time for each image overlaps the readout time for the
previous image. This is a normal situation that typically occurs when a camera is operating at near
to its maximum allowed frame rate (and for the purposes of this example, we will assume that we
are using a camera with a 30 fps maximum allowed rate). Exposure and readout can overlap as
shown in the figure as long as the exposure for a new image does not end before the readout of the
previous frame is complete. The camera will manage the image capture process to make sure that
this rule is not violated.
Camera Controlled Capture 1
= sensor exposure
= sensor readout
Camera Controlled Capture 2
Camera Controlled Capture 3
1/30th s
1/30th s
Camera Controlled Capture 4
Camera Controlled Capture 5
1/30th s
1/30th s
Camera Controlled Capture 6
1/30th s
Camera Controlled Capture 7
1/30th s
Time
Fig. 1: Normal Image Capture - Near Max Frame Rate
2
Application Notes
IP Camera Real-Time Trigger
Figure 2 illustrates how the real-time trigger feature works. When the user applies a trigger signal
to a properly configured I/O port on the camera, the camera immediately begins to abort any image
captures that are currently in progress. The amount of time that the abort process requires is called
the "abort time". At the end of the abort time, the camera begins a new image capture (i.e., it starts
the exposure for a new image). When the capture process for the real-time triggered image is
complete, the image will be transmitted from the camera. The user can be sure that the exposure
for this image started exactly "abort time" milliseconds after the real-time trigger signal was received
by the camera. For example, if the abort time for the camera model you are working with is seven
milliseconds, an image capture will start exactly seven milliseconds after a real-time trigger signal
is applied to a properly configured port on the camera.
Note that the abort time may vary from camera model to camera model.You should check the
camera user’s manual to determine the abort time for the model you are using.
At some point after the abort process ends, the camera will revert to its normal internal method of
triggering the start of image capture. In the case of our example, this will happen 1/30th of a second
after the end of the abort because we are operating at 30 frames per second.
Real-time
Trigger
Applied
Camera Controlled Capture 1
= sensor exposure
= sensor readout
Camera Controlled Capture 2
These two image captures will
be aborted and dropped.
Camera Controlled Captur
1/30th s
C
1/30th s
Real-Time Triggered Capture
1/30th s
A
B
O
R
T
Camera Controlled Capture 5
Camera Controlled Capture 6
1/30th s
Abort
Time
1/30th s
Time
Fig. 2: Real-Time Trigger Image Capture - Two Captures Dropped
Because the real-time trigger operates at the sensor level, it impacts all enabled
streams. So, for example, if you have three streams enabled, each image capture
initiated by a real-time trigger signal will be transmitted in all three streams.
If you take a close look at Figure 2, you will notice that two of the image captures triggered by the
camera’s internal process were aborted. These two partially completed images will be dropped and
will not be transmitted from the camera. Note that if you have several streams enabled, the images
will dropped from every stream.
Application Notes
3
IP Camera Real-Time Trigger
In Figure 2, the real-time trigger was received during the period when two images captures were
overlapped, so both of these captures were affected by the abort and they were both dropped. But
the number of dropped images can actually vary from no images to two images depending on how
you are operating the camera.
Figure 3 illustrates a slightly different situation than Figure 2. In this case, the trigger is not received
during the time when two image captures are overlapped, but rather when the capture process is
only happening for one image. In this case, only one image capture will be aborted and dropped.
Camera Controlled Capture 1
Real-time
Trigger
Applied
Camera Controlled Capture 2
1/30th s
= sensor exposure
= sensor readout
This image capture will
be aborted and dropped.
Camera Controlled Capture 3
Camera C
1/30th s
1/30th s
A
B
O
R
T
Real-Time Triggered Capture
Camera Controlled Capture 5
1/30th s
Abort
Time
Camera Controlled Capture 6
1/30th s
Time
Fig. 3: Real-Time Trigger Image Capture - One Capture Dropped
4
Application Notes
IP Camera Real-Time Trigger
Figure 4 illustrates a different mode of camera operation. In this case, we will assume that we have
set the camera to operate at 15 fps rather than at 30 fps. With the camera set for 15 fps, it will start
a new image capture every 1/15th of a second. Because the camera is set to operate at a much
lower frame rate, the image capture operations will not overlap as we saw earlier, rather they will
be spread out as shown in Figure 4.
Camera Controlled Capture 1
= sensor exposure
= sensor readout
Camera Controlled Capture 2
Camera Controlled Capture 3
1/15th s
Camera Controlled Capture 4
1/15th s
1/15th s
Time
Fig. 4: Normal Image Capture - Lower Frame Rate
Now let’s see what can happen if you apply a real-time trigger when the camera is operating this
way. Figure 5 shows what will happen if the trigger arrives while an image capture is in progress. In
this case, one capture will be aborted, meaning that one image will be lost.
Real-time
Trigger
Applied
= sensor exposure
This image capture will
be aborted and dropped.
Camera Controlled Capture 1
= sensor readout
Camera Contro
1/15th s
A
B
O
R
T
Real-Time Triggered Capture
Camera Controlled Capture 3
1/15th s
Abort
Time
Time
Fig. 5: Real-Time Trigger Image Capture - One Capture Dropped
Application Notes
5
IP Camera Real-Time Trigger
Figure 6 shows what will happen if the trigger arrives during the time between the end of one
capture and the start of the next. In this case, the abort will not affect any image captures and
therefore no captures will be lost.
Real-time
Trigger
Applied
Camera Controlled Capture 1
= sensor exposure
= sensor readout
Camera Controlled Capture 2
Real-Time Triggered Capture
1/15th s
A
B
O
R
T
Camera Controlled Capture 3
1/15th s
Abort
Time
Time
Fig. 6: Real-Time Trigger Image Capture - No Captures Dropped
So in summation, the number of image captures that will be aborted and lost can vary between zero
and two depending on how you are operating the camera and on when the real-time trigger signal
arrives at the camera. If you are operating the camera near to its maximum frame rate, you will lose
one or two image captures depending on when the trigger signal arrives. If you are operating the
camera well below its maximum allowed frame rate, you will lose zero or one image capture
depending on when the trigger signal arrives.
6
Application Notes
IP Camera Real-Time Trigger
2 Using Real-Time Triggering
2.1 Enabling Real-Time Triggering
Enabling Triggering Using the Web Client
To enable real-time triggering via the Basler Surveillance Web
Client, use the Digital I/O tab in the Input/Output parameters
group to properly configure one of the I/O ports. The port should
be configured with the Direction parameter set as an "Input" and
the Function parameter set as "Real-time Trigger" as shown to
the right.
If the invert function for the port is not enabled (i.e., the Invert
check box is not checked), an image capture will be triggered
whenever the electrical signal applied to the port causes the port
to transition from the inactive to the active condition.
If the invert function for the port is enabled (i.e., the Invert check box is checked), an image
capture will be triggered whenever the electrical signal applied to the port causes the port to
transition from the active to the inactive condition.
The State check box indicates the state of the port. The box will be checked when the state is
active and unchecked when the state is inactive.
Enabling Triggering Using the Camera API
To enable real-time triggering via the camera API, use the following parameters in the IO group:
„
Use IOSelector to select a port.
„
Use Direction to set the selected port’s direction to "Input".
„
Use Function to set the selected port’s function to "RealtimeTrigger".
With these settings, an image capture will be triggered whenever the electrical signal applied to the
port causes the port to transition from the inactive to the active condition.
„
If desired, use Invert to set the selected port to invert:
When the invert function for the port is enabled, an image capture will be triggered whenever the
electrical signal applied to the port causes the port to transition from the active to the inactive
condition.
„
If desired, use State to check the current state of the selected port.
Application Notes
7
IP Camera Real-Time Trigger
Note that you can configure more than one port to act as an input with the function
set to real-time trigger. In this situation, an image capture will be triggered anytime
the proper electrical signal is applied to one of the ports.
For information about wiring the ports and about the electrical requirements for the
ports, see the "Terminal Connector" section of the camera user’s manual.
8
Application Notes
IP Camera Real-Time Trigger
2.2 Real-Time Triggering’s Impact on
Streams
Considerations When Using the Web Client
When you are setting the Streaming group parameters on the
camera, remember that because the real-time trigger operates at
the sensor level, it impacts all enabled streams. So, for example,
if you enable three streams, each image capture initiated by a
real-time trigger signal will be transmitted in all three streams.
If the Encoder Type parameter for a stream is set to "JPEG",
"MPEG4", "H.264 Base Profile" or "H.264 High Profile", the
images captured as a result of the real-time trigger will be
transmitted from the camera as part of the normal image stream
as illustrated in Figure 2 on page 3.
If the Encoder Type parameter for a stream is set to "JPEG
(triggered)" as shown to the right, the stream will only include
images captured as a result of using the real-time trigger. The
images in the stream will be motion JPEG encoded.
Considerations When Using the Camera API
When you are using the API to set the values in the Stream parameters group, remember that
because the real-time trigger operates at the sensor level, it impacts all enabled streams. So, for
example, if you enable three streams, each image capture initiated by a real-time trigger signal will
be transmitted in all three streams.
If the EncoderType parameter for a stream is set to "JPEG", "MPEG4", "H_264" or "H_264_High",
the images captured as a result of the real-time trigger will be transmitted from the camera as part
of the normal image stream as illustrated in Figure 2 on page 3.
If the EncoderType parameter for a stream is set to "JPEG_TRIGGERED", the stream will only
include images captured as a result of using the real-time trigger. The images in the stream will be
motion JPEG encoded.
Application Notes
9
IP Camera Real-Time Trigger
2.3 Real-Time Triggering and Alarms
Setting the Alarm Functionality Using the Web Client
If you have enabled real-time triggering as described in Section 2.1 on page 7, then you can set
the camera so that an alarm condition will be declared whenever a real-time trigger is applied.
If the Source Enable check box on the Digital In tab in the Alarm
Sources section of the Alarm Handling parameters group is
checked as shown to the right, the camera will declare an alarm
condition whenever a real-time trigger signal is applied to the
camera.
If you want the camera to send an email with attached images
when an alarm condition is declared, set the parameters on the
Email tab in the Alarm Actions section of the Alarm Handling
parameters group as shown to the right. For each JPEG
encoded stream, the email will include an attached image that
was captured when the real-time trigger signal caused the alarm
condition. The size of each image will be determined by the AOI
settings for the stream in which the image was included.
If you want the camera to send an HTTP request when an alarm
condition is declared, set the parameters on the HTTP tab in the
Alarm Actions section of the Alarm Handling parameters group
as shown to the right.
You must enter a valid URL request in the HTTP URL line. You
could, for example, enter this request:
http://MyServer/cgi-bin/alarm.cgi
You should be aware that the camera will automatically add the
following two parameters to the end of the request:
?host=<hostname>&date=<date/time>
where "hostname" is the camera’s host name and "date/time" is
the current date and time.
10
Application Notes
IP Camera Real-Time Trigger
If you want the camera to upload a text file and image files to an
FTP server when an alarm condition is declared, set the
parameters on the FTP tab in the Alarm Actions section of the
Alarm Handling parameters group as shown to the right. When
an alarm condition is declared, a text file containing information
about the alarm will be uploaded to the FTP server. Along with
the text file, an image file will be uploaded from each JPEG
encoded stream. The image from each stream will be the one
that was captured when the real-time trigger signal caused the
alarm condition. The size of each image will be determined by
the AOI settings for the stream in which it was included.
If you want the camera to make an I/O port change state when
an alarm condition is declared, you must do two things:
„
Set the parameters on the Digital Output tab in the Alarm
Actions section of the Alarm Handling parameters group as
shown to the right. When the Action Enable box checked,
the camera will change the state of a properly configured I/O
port when an alarm condition is declared. The camera will
hold the I/O port in the changed state for a time period
determined by the Digital Output Hold Time [ms] parameter
setting.
„
Properly configure the I/O port.
On the Digital I/O tab in the Input/Output parameter group,
select the tab for the I/O port you want to use (I/O 0 is used
for this example). Set the Direction parameter to Output and
the Function parameter to Alarm Announce.
If the invert function for the port is not enabled (i.e., the Invert
check box is not checked), the port to transition from the
inactive to the active state when an alarm is declared. It will
remain in that state for a time period equal to the Digital
Output Hold Time setting and then will return to the inactive
state.
If the invert function for the port is enabled (i.e., the Invert check box is checked), the port will
transition from the active to the inactive state when an alarm is declared. It will remain in that
state for a time period equal to the Digital Output Hold Time setting and then will return to the
active state.
The State check box indicates the state of the port. The box will be checked when the state is
active and unchecked when the state is inactive.
Application Notes
11
IP Camera Real-Time Trigger
Setting the Alarm Functionality Using the Camera API
If you have enabled real-time triggering as described in Section 2.1 on page 7, then you can set the
camera so that an alarm condition will be declared whenever a real-time trigger is applied. Use the
API to set the following parameters in the Alarm parameters group:
„
Use SourceSelector to select "PIO" as the alarm source.
„
Use SourceEnable to enable the selected source.
If desired, you can set the camera to send an email with attached images when an alarm condition
is declared. For each JPEG encoded stream, the email will include an attached image that was
captured when the real-time trigger signal caused the alarm condition. The size of each image will
be determined by the AOI settings for the stream in which the image was included.
To set the camera to send an email with images when an alarm condition is declared, use the
following parameters in the Alarm parameters group:
„
Use ActionSelector to select "Email" as the alarm action.
„
Use ActionEnable to enable the selected action.
„
Use ActionIncludeImage to enable the sending of images attached to the email.
„
Use Email to enter a recipient address.
„
Use EmailFrom to enter a sender’s address.
„
Use EmailServer to enter an SMTP server to use to send the mail.
„
Use EmailPort to set the port to use on the target email server.
„
Use EmailUserName to specify a user name for authentication on the SMTP server.
„
Use EmailPassword to specify a password for authentication on the SMTP server.
If desired, you can set the camera to send an HTTP request when an alarm condition is declared.
You could, for example, set the camera to send this request: http://MyServer/cgi-bin/alarm.cgi
You should be aware that the camera will automatically add the following two parameters to the end
of the request:
?host=<hostname>&date=<date/time>
where "hostname" is the camera’s host name and "date/time" is the current date and time.
To set the camera to send an HTTP request, use the following parameters in the Alarm parameters
group:
„
Use ActionSelector to select "HTTP" as the alarm action.
„
Use ActionEnable to enable the selected action.
„
Use the HTTPURL parameter to enter the request.
12
Application Notes
IP Camera Real-Time Trigger
If desired, you can set the camera to upload a text file and image files to an FTP server when an
alarm condition is declared. The text file will contain information about the alarm condition. An
image file will be uploaded from each JPEG encoded stream. The image included from each stream
will be the one that was captured when the real-time trigger signal caused the alarm condition. The
size of each image will be determined by the AOI settings for the stream in which it was included.
To set the camera to upload a text file and images, use the following parameters in the Alarm
parameters group:
„
Use ActionSelector to select "FTP" as the alarm action.
„
Use ActionEnable to enable the selected action.
„
Use ActionIncludeImage to enable the sending of images along with the text file.
„
Use FTPServer parameter enter an FTP server to receive the upload.
„
Use FTPRemoteDir to set a path to a target subdirectory for upload.
„
Use FTPPort to set the port to use on the target FTP server.
„
Use FTPUserName to specify a user name for authentication on the FTP server.
„
Use FTPPassword to specify a password for authentication on the FTP server.
If desired, you can set the camera to change the state of a properly configured I/O port when an
alarm condition is declared. Begin by setting the following parameters in the Alarm parameters
group:
„
Use ActionSelector to select "PIO" as the alarm action.
„
Use ActionEnable to enable the selected action.
„
Use PIOHoldTime to set a time in milliseconds that the port will be held in the changed state
after an alarm condition is declared.
Next, use the following parameters in the IO group to configure the port:
„
Use IOSelector to select a port to configure.
„
Use Direction to set the selected port to act as an "Output".
„
Use Function to set the function of the selected port to "AlarmAnnounce".
With these settings, the port to transition from the inactive to the active state when an alarm is
declared. It will remain in the active state for a time period equal to the Digital Output Hold Time
setting and then will return to the inactive state.
„
If desired, use Invert to set the selected port to invert:
When the invert function for the port is enabled, the port will transition from the active to the inactive
state when an alarm is declared. It will remain in the inactive state for a time period equal to the
Digital Output Hold Time setting and then will return to the active state.
„
If desired, use State to check the current state of the selected port.
Application Notes
13
IP Camera Real-Time Trigger
2.4 Minimum Time Between Trigger Signals
As described in Section 1 on page 1, when a real-time trigger signal is applied to a properly
parameterized camera, the camera will immediately begin an abort process and it will start an
image capture as soon as the abort time has expired. Once a trigger signal has been applied to the
camera and an abort process has started, the camera cannot react to a new real-time trigger signal
until a certain minimum amount of time has passed. If a new real-time trigger signal is applied to
the camera before the minimum time has passed, the camera will simply ignore the new trigger
signal.
To determine the minimum required time between real-time trigger signals, you must know two
values: the camera’s current Frame Rate Mode parameter setting and its current Exposure Time
Limit parameter setting.
Using the current Frame Rate Mode setting, you can calculate the camera’s current frame period
with this formula:
Frame Period = 1 / Current Frame Rate Mode parameter setting
And now you can determine the minimum time between triggers:
„
If the Exposure Time Limit parameter setting is > the frame period:
Min Time Between Triggers = ( 2 x Exposure Time Limit) + Abort Time
„
If the Exposure Time Limit parameter setting is ≤ the frame period:
Min Time Between Triggers = ( 2 x Frame Period) + Abort Time
Note that the abort time may vary from camera model to camera model.You should check the
camera user’s manual to determine the abort time for the model you are using.
When you have applied a real-time trigger signal to the camera, the "min time
between triggers" represents the smallest amount of time that you must wait
before the camera is guaranteed to be able to react to a new real-time trigger
signal. In some cases, the camera may be able to react to a new trigger signal
sooner, but this is not guaranteed. If a real-time trigger signal is received too early,
the camera will ignore the trigger signal.
The camera will never abort an image capture that was initiated by the application
of a real-time trigger signal.
14
Application Notes
IP Camera Real-Time Trigger
If you are parameterizing the camera
using the Basler Surveillance Web
Client, you can find the Frame Rate
Mode parameter setting on the Global
tab in the Streaming parameters
group and you can find the Exposure
Time Limit parameter setting on the
Exposure tab in the Image Controls
group as shown at right.
If you are using the API to set camera parameters, you can read the value of the FrameRateMode
parameter in the Sensor parameters group and the value of the ExposureTimeLimit parameter in
the ImageControls parameter group to obtain the required information for the calculations.
Application Notes
15
IP Camera Real-Time Trigger
2.5 Accessing a Stream Set for "JPEG
(triggered)" Encoding
For normal streams (i.e., streams set for JPEG, MPEG-4, or H.264 encoding), the TCP connection
to the host will be closed by the camera if the camera does not have any new images to send for a
period of 10 seconds. Since a stream using "JPEG (triggered)" encoding will not be continuous and
may have periods longer than 10 seconds with no images available for transmission, a new mode
was required for use with requests to access a "JPEG (triggered)" encoded stream. The new
"triggered" mode was added for use when accessing streams encoded as "JPEG (triggered)".
Example 1 Using the Stream Oriented Approach for Stream Access
Assume that you are using a camera with the host name set to IPCam_1. Also assume that you
have stream 1 set for the "JPEG (triggered)" encoder type (and therefore stream 1 is only encoding
and streaming images that were triggered by the camera’s real-time trigger function). To access the
images from stream 1, you would issue this request:
http://IPCam_1/cgi-bin/mjpeg?stream=1&mode=triggered
Example 2 Using the Buffer Oriented Approach for Stream Access
Assume that you are using a camera with the host name set to IPCam_1 and that stream 0 is set
for the "JPEG" encoder type. Also assume that stream 1 is set for the "JPEG (triggered)" encoder
type (and therefore stream 1 is only encoding and streaming images that were triggered by the
camera’s real-time trigger function). You would access the images from stream 1, in this manner:
Begin the process by requesting a list of available streams:
http://IPCam_1/cgi-bin/stream?list
Assume that you receive the following return
buffer_0=(0,"stream 0",image/jpeg,LIVE,1280x960)
buffer_1=(0,"stream 0",image/jpeg,ALARM,1280x960)
buffer_2=(1,"stream 1",image/jpeg,TRIGGERED,1280x960)
To access the images from stream 1, you would issue this request:
http://IPCam_1/cgi-bin/mjpeg?buffer=2&mode=triggered
16
Application Notes
Revision History
Revision History
Doc. ID Number
Date
Changes
AW00099101000
18 Mar 2011
Initial release of this document.
Application Notes
17
Revision History
18
Application Notes
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