PTZControl

History

This small program is designed to control a Logitech PTZ 2 Pro. The camera was purchased to stream our church services.
Unfortunately, it quickly turned out that the operation with the remote control is possible but cumbersome and inaccurate. The camera was installed directly behind and above the video technician and always pointing back with the remote control was not comfortable.
The control Logitech software shipped with the camera is completely worthless.
So, I made the decision to build a corresponding control program.
Some months later we bought a second camera, and the program was extended by the function to control another camera. A maximum of two cameras are supported.
And finally, I added support for the Logitech Rally.

Where is the basic code from?

It wasn’t easy to get code that shows how to control a PTZ camera.
Finally I contacted Lgoitech and I received download link to the Logitech Collaboration Software Reference Kit (Logitech CSRK)
I found some Lync remote control code in it, that gave me some hints and the guids and usage for the Logitect camera interface.

Used interfaces

The program directly uses the camera media control via the Windows SDK (see links in the source code).
For controlling the zoom functions and the preset functions of the PTZ 2 Pro, Logitech provided me with some example code with defines from the Lync driver.
Logitech internal interfaces are used for:

  • Saving the presets,
  • Getting the presets
  • For step-by-step Pan Tilt camera control (see also the settings dialog: Check “Use LogitechCamera Motion Control”)

Standard controls from the Windows Driver API are used

  • For zoom control
  • For the timer-controlled PT (Pan Tilt) control (see Settings: no check mark at “Use Logitech Camera Motion Control”)This control is the standard.

The program supports tooltips that and you can define them yourself to give the camera presets useful names. (Separate for each camera)

Used environment and libraries

I used the Visual Studoi 2019 Community Edition to develop this program with C++.
MFC and ATL as the library. No additional software is used.
The EXE runs alone, without installing any other files.

Behaviour

The program is always in the foreground and has been designed relatively compact and small, so that you can hover somewhere over your OBS program and it is really easy to use.
Current selected preset or home position are shown with a green background on the buttons.
Recalling a presets are simply done by clicking on one of the number buttons.
Presets are changed by pressing the M button (Memory) followed by a number key. The M button turns red as long as it is active.

The program remembers its last position on the screen and is automatically repositioned to when it is started.
All settings are stored in the registry under the branch HKEY_CURRENT_USER\SOFTWARE\MRi-Software\PTZControl.
See the command line secion too.

Supported Cameras

Currently, the Logitech PTZ 2 Pro and Logitech Rally cameras are automatically detected.
For other cameras, you can try to force detection by specifying the name (or part of the name) of the cameras in the registry or on the command line.

Internally, all cameras that have one of the following tokens in the name are automatically used:

  • PTZ 2 Pro
  • Logi Rally

Guard Thread

Unfortunately, we have sometimes had the experience that OBS or the USB bus hangs with a camera. The PTZControl program then usually stops and stops responding because the camera control commands block the application.
Through an internal guard thread, the application can determine that it is no longer working correctly and terminates automatically.
Otherwise you would have to use the task manager and this can take a lot of time to terminate the application in the hustle and bustle of a livestream.

Logitech Motion Control

The Logitech cameras have their own interface for pan/tilt control. This moves the camera in X/Y Axe by a certain step value, This control is a special Logitech feature.
If you click on a direction button once, exactly one step pulse is output.
If you hold down a direction button, a pulse is sent to the camera again and again at a certain interval to change the direction.

Standard Motion Control

This control is the standard when you start the application for the first time.
I have made the experience that this Logitech motion control is a bit rough. Via the normal device control, a pan/tilt is also possible in corresponding motor commands for X/Y direction. This is done in turning on the motor for a specific time interval and turning it off again.
Accordingly, you can adjust the timer interval for Motor on/off accordingly. The default is 70msec. Values between 70 and 100 or goiod values.
If you click on a direction button once, the motor is turned on and off again after the corresponding interval.
If the direction button remains pressed, the motor remains switched on for the corresponding direction until the button is released again.
This control seems more effective and accurate to me and is the standard. The disadvantage is that if the timer interval is too small, the camera does not react immediately when a button is clicked. But since precision was more important to me because our camera is installed relatively far away from the podium, I use this setting with a 70msec timer.

Command Line Options

A few options can be set from the command line. Command-line switches override the settings in the registry.

-device:”name of device”
The device option can be used to specify a name component of a camera to be used for control.
If you enter “*” as the name, then each camera will be recognized.

-showdevices
Displays a message box after startup showing the name(s) of the detected cameras.

-noreset
At startup, a detected camera is moved to the home position (Logitech Preset) and the zoom is reset to maximum wide angle. If the -noreset option is specified, the camera position remains unchanged.

-noguard
-noguard prevents the application from terminating itself in a controlled manner. This can be especially important in the event of a bug and for testing.

Registry

In the registry branch HKEY_CURRENT_USER\SOFTWARE\MRi-Software\PTZControl\Options it is possible to preset the following options without using the command line.

NoReset (DWORD value
Value <>0: Has the same function as -noreset on the command line. The current camera and zoom position is maintained when starting the program. Value = 0: When starting the program, you move to the home position and zoom to maximum wide angle. (Default)

NoGuard (DWORD value)
Value <>0: The guard thread that may automatically terminate the application is terminated.
Value = 0: The guard thread automatically terminates the application if a blocking of the USB bus is detected. (Default)

GitHub

View Github