How much bandwidth is required for a real time video call?
The amount of bandwidth required for a real time video call depends on the required resolution, frame rate and target bit rate as shown here.
What affects real time video/audio quality?
Three factors influence the video/audio quality:
- Limitations on the device and what it will support.
- Physical resolution of the camera, Graphics Processing Power, CPU, and resource contention by other application features and other applications running in the background.
- An iPad Air has the processing power to support higher resolutions, an iPad 2 does not.
- iPad2 also as an example have known WiFi performance characteristics at various iOS version levels.
- Network Conditions
- Available Bandwidth
- WiFi Spectrum Saturation
- Contention and Packet Loss
- The resilience of the codec to the network conditions
- The CaféX solution supports NACK/PLI and adaptive bit rate control for the video stream which greatly improves resilience to packet loss and changes in bandwidth availability allowing for a higher quality video experience even in less than ideal network conditions.
- However, even this has limitations and logic needs to be employed to address higher thresholds of network problems.
Production Video Quality cannot be achieved without;
- addressing the configuration of the network to support a quality video experience.
- analyzing resource consumption of client devices to ensure enough resources are available to achieve a positive end-user experience. Other background applications can easily effect resource availability.
There needs to be sufficient bandwidth available to support the required resolution, frame rate and target bit-rate - see here for details.
In addition the following constraints exist for an acceptable user experience:
- Packet loss:
- Video – no more than 20% loss
- Audio – no more than 10% loss
- Latency won’t affect the quality but will affect the user experience if it is too high. We recommend no more than 100ms latency between the endpoint and Media Broker.
- Should be no more than 50ms
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