If your IBM
® deployment will include one or more Sametime
Media Manager servers, you should review this information about A/V (audio/video) features.
Media Manager allows configuration of several parameters that effect the bandwidth and performance of audio and video conferences. These parameters default to values which should work for most environments, but they can be tuned to meet the specific needs of the organization deploying Sametime
In the Sametime
System Console, the codecs used for audio and video transfer can be tuned to the values required. The selected audio and video codec will effect the bandwidth used and the processing power required to encode and decode the information streams. Consult the specification of those codecs to determine which one bests suits any specific needs of the deployment.
Within the specification of the video codec, it is also possible to adjust the video resolution and bit-rate which will be used for video streams. Generally, the lower the resolution and the bit-rate, the lower the bandwidth used and the lower the processing power required to send and receive the video streams. However, the lower resolutions and bandwidth, the lower the quality of the video image. Likewise, the higher the bit-rate and resolution, the higher the required bandwidth and processing power, and the higher the quality of the video.
For example, if you are using low bandwidth networks and older machines with less processing power, it might be necessary to select a lower video bit rate. If the quality of the video image is important, and enough processing power and network bandwidth is available, a higher video bit-rate can be used.
video codecs provide many resolution choices, from SQCIF to Wide Full HD (1080p). The higher the resolution, the more CPU, display memory, and graphics card power are required. HD requires Intel
™ Core 2 Quad or better CPU and at least 256 megabytes of display memory.
Another configuration parameter which can be adjusted is the number of switched audio streams. This is the total number of audio streams that will be sent from the server to the client when participating in a audio conference call. The higher the number of audio streams to each client, then the higher the number of people on the call who can speak at the same time and be heard by all participants. The number of streams sent to each client also affects bandwidth and server load.
The total number of participants in audio and video conferences can also be capped, limiting the amount of bandwidth that any single call can use as a sum of the other parameters and the number of people participating in the conference.
As the number of participants in a video conference increases, so does the demand on the network. To ensure that a given network can support this new collaborative feature, administrators have the ability to restrict the maximum number of participants. Administrators should work directly with their network team to identify the maximum number of participants that works best for their organization and their respective network policies. The default maximum number of participants in a single audio-only or video conferences is set to 20; however, this can be adjusted up or down to accommodate specific network consumption requirements. As a best practice, the moderator has the option to mute all
participants. To ensure the best experience possible, the mute all
feature should be exercised to keep background noise to a minimum. Once a user has been muted by the moderator, the user has the option to un-mute
themselves at any time.
Another consideration for networks is latency, which can cause undesirable results. Latency of less than 150ms end-to-end
is normally acceptable in interactive real-time audio video conferencing.
- Video driver
It is strongly recommended that you use the up-to-date driver that comes with the video camera, as some cameras do not work well with the generic video driver
- Video memory
256 MB of video memory required for VGA and above; Minimal 128 MB of video memory for QVGA resolution and below.
IPv6 addressing is not supported for the Sametime
Media Manager or its components.
NAT (Network Address Translator) and firewall support
Starting with release 8.5.2, the Sametime
Reflector has been replaced with the Sametime TURN Server
. The TURN Server enables Sametime
clients running release 8.5.2 or later to send and receive audio and video communications across a NAT (Network Address Translator) or firewall when direct peer-to-peer communications are not possible.
Audio/video bandwidth consumption considerations
The table below outlines maximum bandwidth consumption for Sametime
clients using the default audio and video codecs:
Table 1. Bandwidth consumed by Sametime clients
|Client type ||Connect client|| Web meeting client|
|Max Video (H.264)||384 kbps||384 kbps|
|Max Audio (iSAC)||32 kbps||32 kbps|
- All 8.5.x clients (8.5.0, 8.5.1, and 8.5.2) can interoperate with each other and use any 8.5.0, 8.5.1, or 8.5.2 servers.
- IBM Sametime Connect clients or Sametime embedded clients require a Sametime Media Manager server running Release 8.5.1 or later to be able to make or receive computer audio (voice chat) or video calls.
- Microsoft™ Windows™ XP Tablet PC is not supported.
- Sametime Media Manager includes additional security and audio-visual quality features that work with clients running Release 8.5.1 or later only. To support 7.5.x, 8.0.x, or 8.5 clients running on an 8.5.1 or later server, disable these features until all clients are running 8.5.1 or later:
If you leave these features enabled, 8.5 and earlier clients cannot use audio-visual features provided by the Media Manager.
- Clients running releases earlier than 8.5.2 cannot have audio and video communications across a NAT (Network Address Translator) or firewall.
The softphone provided by Sametime
uses the email field for user identification. To support audio video communications, the LDAP directory must have the email field populated for every user.
For information on using the best practices for ensuring a good audio/visual experience, see Audio/Visual Best Practices
in the Sametime
Parent topic: Planning a Sametime Media Manager installation on Linux or Windows
Changing the default number of maximum users