Microsoft Research ConferenceXP: ConferenceXP Frequently Asked Questions (FAQs)

If I want to try ConferenceXP, what hardware do I need?
For ConferenceXP system requirements and recommended hardware, see the ConferenceXP Client 3.2 Installation Guide and the ConferenceXP Classroom Setup Guide.

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Can I use more than one camera with ConferenceXP?
Yes, ConferenceXP 3.0 and later support multiple cameras. For more information about the new features and enhancements in ConferenceXP 3.0, see Introducing ConferenceXP 3.0. For more information about the new features and enhancements in ConferenceXP 3.1, see ConferenceXP 3.1 Release Notes. For ConferenceXP 3.1 system requirements and installation instructions, see the ConferenceXP Client 3.2 Installation Guide.

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Can I run ConferenceXP on a laptop computer?
Yes, but the quality of video conferencing in ConferenceXP rapidly degrades when the system nears or hits 100% CPU utilization, so we recommend you monitor the CPU utilization and use high-end laptop hardware. In our observations, a laptop with a Pentium III 1.2 GHz processor with the NVIDIA Quadro2 Go Graphics Processing Unit (GPU) can do two-way conferencing, and a laptop with a Pentium IV 2.0 GHz processor with the NVIDIA GeForce4 Go GPU can do five-way conferencing. In both cases, the laptops are plugged into a power outlet to prevent the CPU from running at a lower speed to save power and the laptops use 100BaseT wired networking. For more information about using wireless networks, see Does ConferenceXP work over wireless networks?.

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Does ConferenceXP work over a wireless network?
ConferenceXP 3.0 and later include enhancements that enable better transmission of slides and ink over wireless networks. However, these enhancements do not affect the quality of audio and video transmission over wireless networks. Generally, wireless networks do not have sufficient bandwidth and quality of service to support transmitting high-bitrate, high-quality audio and video streams.

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Can I run ConferenceXP on Windows Server 2003?
If the Windows Media codec that ConferenceXP requires is installed (which is included with Windows Media Player), you can run ConferenceXP on Windows Server 2003. However, because we support running ConferenceXP on Windows XP, we have not done extensive testing of ConferenceXP running on Windows Server 2003.

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Can ConferenceXP be deployed on a multicast-enabled intranet with no Internet connectivity?
Yes it can, although it will require port TCP/80 (also known as HTTP Port for SOAP) connectivity either directly or through a proxy server which must be specified in the Internet Explorer Connectivity settings to communicate with the Venue Server to find the venue and participant information it needs to function.

To be entirely self contained, you can run a venue server on your intranet and keep that TCP/80 traffic internal too. There’s a *.config file for each client that has a URL that can be changed to point to a local venue server.

In the case that TCP/80 is closed, a HTTP proxy is not set up, and the client has not been redirected to a local venue server, then the client is unable to get a hold of venue or participant information. When this happens, a default mode is used to allow the client to continue working, though with only one default venue to select from.

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Does ConferenceXP require a server for receiving and sending streams?
ConferenceXP employs a peer-to-peer architecture. Because no server is involved, this architecture makes deployment easy, and it prevents network traffic bottlenecks and single points of failure.

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Can I use ConferenceXP without Windows Messenger or Passport?
You do not need to have Windows Messenger running to run ConferenceXP; it will automatically roll over to your Windows credentials if Messenger is not and has never been run under that account. We do plan to authenticate your Profile entry on our Venue Server using Passport in the future when Passport and Web Services have been integrated. We publish the Venue Server binaries and source code so setting up your own Venue Server using either Windows or a custom (or no) authentication method would be possible.

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Why does ConferenceXP use Windows Media codecs?
Video conferencing requires low latency and not all video codecs can do this. When we started designing ConferenceXP, we found that the Windows Media Video codecs, included with Windows Media Player, met all our latency and bandwidth requirements, worked well, and is free with your Windows XP license, which is the supported operating system. ConferenceXP 3.0 and later use the Windows Media 9 Series Audio and Video Codecs.

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How are ConferenceXP multicast addresses selected?
The specific IP address chosen is determined by what venue is selected. One IP address is statically bound to each venue. When two ConferenceXP clients join the same venue, they are talking on the same multicast address and can see each other.

The Venue Server contains a database that maps friendly Venue names onto the IP addresses.

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Which multicast addresses does ConferenceXP use?
ConferenceXP uses a range of 233.45.17.172-175:5004/5005 as well as a range of ‘non-routed’ multicast addresses in 234.*.*.*.

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Are ConferenceXP video signals multicast?
Yes, ConferenceXP sends RTP and RTCP packets over multicast UDP/IP.

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Is ConferenceXP compatible with my existing video conferencing system?
No, ConferenceXP uses the Windows Media codecs, which have been highly optimized for quality and efficiency on personal computers. Most commercial video conferencing systems today are based on the h.261 or h.263 video codecs, which provide relatively poorer quality and higher CPU utilization.

ConferenceXP transports its data over RTP (Real-Time Transport Protocol), described in RFC 3550 from the IETF. If you’re a researcher interested in working with us to implement a backwards compatibility solution, let us know.

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Can I run Conference 3.x and ConferenceXP 2.4.2 on the same computer?
Because ConferenceXP 3.x includes major changes at the networking and audio/video levels, having both ConferenceXP 2.4.2 and ConferenceXP 3.x installed at the same time is not supported.

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Which video devices does ConferenceXP support?
For a complete list of the cameras, video capture cards, and video drivers we’ve tested with ConferenceXP 3.0 and later, see ConferenceXP Supported Video Devices.

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Troubleshooting

Why does ConferenceXP 3.x take a long time to start?
Because Venue Service has a 10-second timeout, ConferenceXP will take at least 10 seconds to start. During startup, ConferenceXP also checks Windows Messenger to get your identifier.

Make sure Windows Messenger is not causing the problem:

Do one of the following:

Make sure Windows Messenger is working properly by restarting your computer and then restarting Windows Messenger. (To restart Windows Messenger, on the Start menu, point to All Program, and then click Windows Messenger.)
Temporarily uninstall Windows Messenger.

Start ConferenceXP again.

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How do I troubleshoot multicast network problems?
If Multicast isn’t working at your site, try the following:

Use the Connectivity Detector network diagnostic utility.
Follow the tutorial on diagnosing multicast problems for the Access Grid.
In ConferenceXP, create a peer-to-peer connection by starting a two-way conference over unicast.
Create a unicast bridge by using the ConferenceXP Reflector Service.

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Why can’t I see other participants in a venue?
It is possible to view and enter a ConferenceXP venue without Internet2 and multicast connectivity. However, unless you have Internet2 and multicast connectivity, you will be unable to view other participants in the venue or send and view video and audio streams.

To determine if you have Internet2 and multicast connectivity, use the Connectivity Detector (ConferenceXP 3.x) or Pipecleaner Stoplight (ConferenceXP 2.4.2 and earlier) network diagnostic utility. This utility checks your networking connectivity and directs you to troubleshooting information if the connectivity check fails. For more information, see About Internet2 and Multicast Connectivity.

To use the network diagnostic utility included with ConferenceXP, do one of the following:

In ConferenceXP 3.x, on the Settings menu, click Start Connectivity Detector.
In ConferenceXP 2.4.2, on the Help menu, click Internet2 & Network Connectivity.

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How can I prevent lost ink or slides in a wireless network?
If you notice symptoms of poor network conditions, such as lost slides or ink strokes, try the following:

If you’re using a laptop with Intel Centrino mobile technology, the power save polling feature may be interfering with wireless connections. To prevent this problem, see PSP (Power Save Polling) Causes Connection Issues With Some Access Points.
Try adjusting ConferenceXP for poor network conditions. For more information, see Is there a way to adjust ConferenceXP for poor wireless network conditions?

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Is there a way to adjust ConferenceXP for poor network conditions?
If you’re using ConferenceXP in less than optimal network conditions, you may experience performance issues, such as lost slides or ink strokes. To prevent or workaround this problem, try the following:

If you’re using a laptop with Intel Centrino mobile technology, the power save polling feature may be interfering with wireless connections. To prevent this problem, see PSP (Power Save Polling) Causes Connection Issues With Some Access Points.
To minimize these symptoms of poor network conditions, you can increase the forward error correction (FEC) ratio, decrease the data throughput, or both.

Increase the FEC ratio for capabilities

Open the CXPClient.exe.config file in a text editor, such as NotePad.
Edit the value for the following key:

<add key="MSR.LST.ConferenceXP.Capability.<CapabilityName>.FecRatio" value="0:50"/>

where 50 is the default FEC ratio, indicating the ratio of checksum packets to data packets sent. Increasing this value causes ConferenceXP to send more checksum packets, which enables more data packets to be reconstructed if lost.

Decrease the rate of data being sent for capabilities

Open the CXPClient.exe.config file in a text editor, such as NotePad.
Edit the value for the following key:

<add key="MSR.LST.ConferenceXP.Capability.<CapabilityName>.MaxBandwidth" value="256000"/>

where 256000 is the amount of data sent over the network, in bytes per seconds. Decreasing this value causes ConferenceXP to send data over the network less frequently, which decreases network traffic.

For ConferenceXP applications (that is, non-capabilities), you can change these values on the RTP sender.

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How do I prevent video problems on my computer?
If you see video problems on your computer, such as several videos in the same window or not seeing your video on your computer while other participants can see your video, there may be a conflict with your graphics card. To determine if this is the problem, do the following:

Disable the DirectDraw Acceleration feature

On the Start menu, click Run.
In the Open box, type dxdiag.
Click the Display 1 tab.
Under DirectX Features, next to DirectDraw Acceleration: Enabled, click Disable.

(Click for a larger image)
If you have a second monitor, click the Display 2 tab, and then next to DirectDraw Acceleration: Enabled, click Disable.

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Why can’t I and others not hear or see my audio or video?
If you and others cannot see or hear your video or audio stream, make sure your video or audio device is working properly. To do so, determine if your audio and video works in other programs to see if the problem is with your audio or video device or if the problem occurs only in ConferenceXP.

Determine if your camera or audio device works as expected in another program

Do one of the following:
- Use the Audio and Video Tuning Wizard feature in Windows Messenger.
- On the Start menu, click Control Panel. Click Scanners and Cameras, and then click your video device to see if it displays an image.
- Open Microsoft Movie Maker, or another program that can capture audio and video from your camera or audio device, and then make sure your camera or audio device works as expected.

If your audio or video device does not work in other programs, you’ll need to troubleshoot that problem. If your audio or video device does work in other programs, but not in ConferenceXP, see the ConferenceXP Message Boards or Distribution Lists for troubleshooting help.

Tip If you’re using a firewire camera and no image appears, try resetting your firewire camera by removing and replacing the firewire cable from the back of your computer or camera. This removes power from the camera and resets the device.

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How do I prevent running out of virtual memory in ConferenceXP 2.4.2?
In ConferenceXP 2.4.2, if your monitor power settings are set to turn off while ConferenceXP video streams are running, the video stream does not appear on the monitor, but the DirectX component of ConferenceXP continues to buffer the stream. This can quickly cause your system’s memory to be depleted, resulting in the message, “Your system is low on virtual memory.” This problem is fixed in ConferenceXP 3.0 and later.

You can avoid this problem in ConferenceXP 2.4.2 by stopping ConferenceXP streams before you leave your computer, by adjusting your monitor power setting to never turn off, or both.

Stop a stream

In the ConferenceXP 2.4.2 venue window, right-click the icon you want, and then click the stream you want to stop.

Adjust the monitor power setting to never turn off

In Control Panel, click Display.
Click the Screen Saver tab.
Under Monitor power, click Power.
In the Turn off monitor list, click Never.

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Why is my ConferenceXP 2.4.2 video stream out of sync with current events?
In ConferenceXP 2.4.2, if you have the monitor power set to turn off after a specified amount of time when you’re running ConferenceXP, the ConferenceXP video stream is interrupted. When you resume using the computer, which restores power to the monitor, ConferenceXP starts the video stream. The video stream starts where it left off, playing a delayed stream compared to actual events at a faster speed while DirectShow clears the cache. To avoid this problem, which also uses up available memory, adjust the monitor power setting to never turn off.

Adjust the monitor power setting to never turn off

In Control Panel, click Display.
Click the Screen Saver tab.
Under Monitor power, click Power.
In the Turn off monitor list, click Never.

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Venue Service

How does Venue Service work to get clients talking?
Venue Service uses the standard unicast HTTP protocol to communicate with clients. The clients submit requests and get results just like they were submitting a form request.

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What are the hardware requirements for Venue Service?
Venue Service is a very lightweight Web service-SQL Server application, so it should run on any computer that can run Microsoft SQL Server™ 2000 Personal or Developer Edition or Microsoft SQL Server 2000 Desktop Engine (MSDE) 2000. For more information, see the ConferenceXP Venue Service 2.1 Installation Guide.

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After I install Venue Server on Windows Server 2003, why can't I see the list of venues?
If you have installed Venue Server on Windows Server 2003 and cannot see your list of venues, make sure that the status of the ASP.NET Web Service Extension in IIS Manager is set to Allowed.

Change the status of the ASP.NET Web Service Extension in IIS Manager

Open the Internet Information Services (IIS) Manager.
Under REFLECTOR (local computer), click Web Service Extensions.
In the right pane, click ASP.NET, and then click Allow.

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Why can't participants see the venues?
If only the Local Venue appears for participants connecting to your Venue Service, make sure port 80 (HTTP Port) is open on the Venue Service computer.

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Connectivity Detector and Pipecleaner

Are the Connectivity Detector (previously known as Pipecleaner) packets unicast or multicast?
Connectivity Detector (ConferenceXP 3.0 and later) and Pipecleaner Stoplight (ConferenceXP 2.4.2 and earlier) send RTP and RTCP packets over multicast UDP/IP. They use 233.45.17.171:5004 for RTP and 233.45.17.171:5005 for RTCP. For more information, see About Internet2 and Multicast Connectivity.

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Source Code

Why does an unhandled exception error occur when I build the ConferenceXP Client (Bar UI) solution?
If the error, “An unhandled exception of type ‘System.DllNotFoundException’ occurred in mdshowmanager.dll. Unable to load DLL (netrenderer.ax).” occurs when you run the “ConferenceXPClient (Bar UI)” solution, do the following:

Manually copy the netrenderer.ax and netsource.ax files from their build directories under DShow\* into the directory from which you are going to run BarUI.exe.

Unfortunately, Microsoft Visual Studio .Net does not have a way of specifying unmanaged (older Win32) code dependencies for a managed (.NET) project and these are the files ConferenceXP uses to link its managed conferencing logic into the DirectShow APIs.

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