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Preferred StarLeaf bit rate

StarLeaf uses the following bit rates and resolutions:

Room system / client Max bit rate Audio (StarLeaf-to-StarLeaf) Max video receive Content
GT Mini + Touch 2045 6 Mbps* 64 kbps AAC-LD 1080p30 1080p30
GT Mini + Touch 2036 2.5 Mbps 64 kbps AAC-LD 720p30 1080p30
Huddle 6 Mbps* 64 kbps AAC-LD 1080p30 1080p30
StarLeaf Room for Windows 1.5 Mbps 64 kbps AAC-LD 720p30 1080p12
StarLeaf Room for Poly 1.5 Mbps 64 kbps AAC-LD 720p30 1080p12
StarLeaf app for Windows and macOS 1.5 Mbps 64 kbps AAC-LD 720p30 1080p12
StarLeaf app for Android 448 kbps download, 384 kbps upload 64 kbps AAC-LD 352p 1080p6
StarLeaf app for iPhone 496 kbps 64 kbps AAC-LD 352p30 1080p6
StarLeaf app for iPad (varies depending on model) Up to 1 Mbps 64 kbps AAC-LD 720p30 1080p6
WebRTC 1.5 Mbps 64 kbps AAC-LD 720p30 1080p12
H.323 registered devices (excluding Cisco SX80) 1.5 Mbps 64 kbps AAC-LD 720p30 1080p12
Cisco SX80 2.5 Mbps 64 kbps AAC-LD 720p30 1080p12

*GT Mini with Touch 2045 and Huddle support bit rates up to 6 Mbps. However, by default it is limited to 2.5 Mbps to reduce the load on your internet connection. You can update this in the Portal; see below.

Portal settings for send and receive rates

In the StarLeaf Portal, you can set maximum send and receive rates at site level and on individual endpoints. By default, these are set to Automatic, meaning it will use the preferred bit rate. You can set a lower bit rate or a higher bit rate up to 6 Mbps.

To adjust these rates, go to Portal > Sites > Edit sites and expand Advanced settings.

If you wish to limit the bandwidth used by the endpoints then you can set a value lower than 2.5 Mbps.

To increase video quality you can set higher bandwidths up to 6 Mbps which will apply to room systems with a GT Mini + Touch 2045 or Huddle.

Setting a higher rate than what an endpoint is capable of will have no effect.

Content and video bandwidth split

StarLeaf allocates 64 Kbps to audio. The remaining available bandwidth is split between video and content according to the amount of screen space they take up with a maximum of 3 Mbps each.

Limitations at low bandwidths

StarLeaf tests the available internet bandwidth to determine what bit rate to use up to the preferred rate or the rate set in the Portal. At lower bandwidths, StarLeaf restricts the video quality according to:

Speed test result Description
<152 kbps Bandwidth is too low for video. Only audio calls are possible
<256 kbps Bandwidth is too low for simultaneous video and content sharing. Only audio plus low-quality video or audio plus content sharing is possible
<768 kbps Bandwidth is too low for HD video. Only audio plus lower quality video and content sharing
<1168 kbps Bandwidth is too low for HD video. Only audio plus lower quality video and content sharing
<2.1 Mbps Bandwidth is good enough for audio and HD video
>= 2.1 Mbps Bandwidth is good enough for simultaneous HD video and content sharing. This only applies to room systems

Upstream and downstream bandwidths are tested and set independently of each other, meaning that a low upload speed on an ADSL connection, for example, does not have a negative impact on the quality of a video that an endpoint can receive.

Speed tests

Room systems

To view the current speed test result on your Touch 2045 or Huddle double tap the home button to get to the settings and go to Network. This shows you the most recent upload and download results.

Press Run speed test to re-run the test.

StarLeaf on desktop/mobile

Under the Account tab in your app, you can check your connection speed in Speed test. The speed test advises you of call bandwidth and the quality of video that your app can receive depending on this.

Select Run speed test to check the latest connection status.

If the quality of the video you are experiencing on a StarLeaf call does not meet your expectations, review some possible solutions in StarLeaf app troubleshooter

In-call media statistics

Within a call, the actual bit rate of the audio, video, and content sent and received depends on:

  • the overall call bit rate and
  • the amount of motion and
  • the video capabilities of the other meeting participants

For more information see Call statistics.

StarLeaf app: Platforms with limited processor power

Unlike the hardware-based range of StarLeaf endpoints, the StarLeaf app is designed to install and run on platforms with a widely varying range of capabilities. It is able to reduce the bit rate and resolution of its video channel in line with the capabilities of the host CPU. On a modern full-spec PC or laptop, StarLeaf’s capabilities match those described in section 1 of this article. On lower-powered systems, for example mobile devices, lower bit rates and resolutions are selected in order not to over-power the processor.