Environment from the Molecular Level A NERC eScience testbed project

Use of the Personal Access Grid (PIG), version 1.2

1. Some nuts and bolts

The Access Grid is one of the public successes of the UK eScience programme. With large teams of escience personnel working in several laboratories, it is providing the means for team members to stay in contact, enabling whole group meetings to take place without people needing to travel.

The Access Grid is a set of tools to enable audio/video conferencing via multicast communication. The latter point is what enables many teams to join in a conference at the same time, and what also enables each meeting to broadcast more than one audio and video signal (and for these all to be received). The traditional unicast methods do not scale very well, and large conferences will make heavy demands on the local area networks.

More information about the Access Grid can be obtained from the Access Grid web site.

The Access Grid in its better-known form is based on a set of Access Grid suites around the UK. Each eScience Centre has an Access Grid Suite, with of order 3 camera and 3 area microphones. The images coming into the suite are projected onto a long wall using around 3 video projectors, and sound is broadcast in the suite using quality sounds amplification and loud speakers.

There are many advantages to being able to use an Access Grid suite, including the high quality of the projection and audio system, and the possibility to accommodate several people in each room. There are, however, a number of drawbacks, including the fact that the suites need to be booked in advance in order to guarantee that all partner suites are available at the same time, the fact that the Access Grid suites need to be run by a trained operator, and that there is not an Access Grid suite in every institution. In addition, setting up a suite is not inexpensive. The bottom line is that the traditional realisation of the Access Grid does not permit conferencing "on demand".

The Access Grid developers also package a personal version that can run on a single PC (desktop or laptop). This is called the PIG ("Personal Interface to the Grid") in its Windows version, and PIGLET in its linux version; there is sadly no version for Mac OS X. The participant can put the images onto the desktop rather than needing to project onto a wall, and the audio component of the conference is handled using a microphone/headphone headset combination. The video is recored using a simple webcam. Startup costs are low, and the software can easily be handled by each participant. This facilitates conferencing on demand.

This web page concerns the practical implementation of running the personal Access Grid.

Note that the eMinerals project is currently using version 1.2 of the PIG software. Version 2 is radically different from v 1.2, and compatibility is not assured.

2. Windows version

2.1 Installation

The Windows version is easy to install:

• Download the software from the Access Grid site, and unpack
• You only need to run the installation program, and usually give default answers. The one answer that matters is that you should select the personal option when asked.
• You will be left with two links to the Access Grid on your desktop

2.2 Running through the eMinerals bridge

Using the eMinerals bridge is not the prefered option, but will be necessary if your institution does not support multicast through its networks to your desktop (eg through routers and firewalls). Bridging will work okay for small meetings, but the bridge will become overloaded if there are many users. The bridge will provide unicast networking to your desktop, which bypasses (not solve!) any multicast network problems you face.

To run the personal access grid through the bridge, you need to go to the command line window on windows. You need to connect to the directory

C:\ag\agapps\bin

To institute the access grid session, you need to launch the audio (rat) and video (vic) tools using the following two commands:

rat eminerals.esc.cam.ac.uk/50480
vic eminerals.esc.cam.ac.uk/50482

These will throw up both the audio and video windows:

2.3 Running via multicast (the proper way!)

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3. Linux version

3.1 Installation

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3.2 Running though the eMinerals bridge

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3.3 Running via multicast (the proper way!)

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4. Controlling the audio/video input and output

There are separate programs for the audio and video signals, called rat (robust audio tool) and vic. These have separate sets of windows, and are run independently.

4.1 Audio (rat) window

This window (see above) has two main panes, for input and output audio control. You will see a list of all partners in the input pane.

• Locate the mute checkboxes in the output pane and ensure that it is not checked for mute (otherwise you will not be heard!).
• You have controls on both the output and input sound levels. You can chose the input sound level that suits you best. You are likely to need to set the output level that best suits your colleagues in the access grid session; beware that you do not set this too high initially! The settings shown in the figure above may be found to be a reasonable first estimate.

4.2 Video (vic) window

This window (see above) will show small representations of all incoming video signals, together with a number of options.

• To open one of the video windows in order to properly see the person you are talking to, simsply click on their representation.
• You can control the size of any person's video window by clicking S (for small), M (for medium) and L (for large) when your mouse is over their video window.
• You need to set some of the options in the options menu, accessed from the Menu button on the window (see figure above). The most important one is to click the transmit checkbox, for without this you will not be seen by anyone else!
• The other option worth thinking about is the video rate, which will control both the quality of your output video signal and the refresh rate.

The video menu Important settings are: The transmit box must be checked in order to send video Rate control setting of around 500 appears to work reasonably well (but may depend on system) Encode setting of around 20 appears to work reasonably well (but may depend on system) Quality setting of 1 appears to work reasonably well (but may depend on system) You can change the session name to show your name if your computer is used by several users