Network Performance

Media Quality Types

Quality measurement in video conferencing systems involves assessing both the outgoing and incoming media quality being received by the peer. Media quality can be observed in two dimensions:

  1. Outgoing or Publisher Media Quality - represents the quality of outgoing audio and video streams sent from a peer's device. It is influenced by factors such as the device's processing power, encoder efficiency, and the available uplink bandwidth.
  2. Incoming or Subscriber Media Quality - represents the quality of incoming audio and video streams received by a peer from other peers in the session. It is primarily impacted by either or both
    • the network conditions on the publishing end from other remote peers.
    • factors like available downlink bandwidth, packet loss, jitter, and the efficiency of the decoder on the receiving local peer.

Network metrics impact media quality

There are several factors on which quality can be measured such as bitrate, jitter, round trip time, packet loss, CPU limitation, network limitation impact incoming and outgoing media quality of a video session.


Bitrate defines the amount of video and audio data sent by the local peer to remote peers per second, measured in bits per second (bps). The maximum achievable outgoing bitrate depends on factors like:

  • RTT, packet loss, and available network bandwidth.
  • Bitrate values configured for the respective role under templates.

Bitrate values

  • Standard bitrate value for audio is 32kbps; for video it can be configured under the template settings.
  • Higher bitrate value means more data per second is being sent, allowing for better video/audio quality. But if the bitrate exceeds network capacity it leads to packet loss and quality degradation.

Frame Rate (FPS)

The frame rate refers to the number of video frames transmitted per second by the local peer to the remote peers in a video call.

Frame rates and video quality

  • Higher outgoing frame rates result in smoother, less choppy video quality at the receiver's end. However, high frame rates require higher bitrates.
  • Lower outgoing frame rates allow the local peer to reduce their transmitted bitrate while maintaining visual quality.

Packet Loss

Packet loss occurs when media packets being sent by the local peer fail to reach the remote peers, resulting in degraded audio/video quality of the peer. It occur due to network congestion, insufficient bandwidth, faulty network hardware, etc.

Measuring Packet loss

  • Some amount of data loss is inevitable, so the severity is measured by the percentage of total packets lost.
  • Packet loss below 5% is generally considered acceptable and normal.
  • Beyond 5%, high outgoing packet loss can significantly degrade the video resolution, frame rate, and image quality observed by remote viewers. Audio can be jittery or broken up or may miss sections of audio.

Round Trip Time (RTT)

Measures the time in milliseconds (ms) it takes for a packet of data to travel from the source(client) to the destination and back again. Higher the RTT, higher the latency.


Jitter refers to the variation in delay between delivered media packets being sent from the local peer to the remote peers. High outgoing jitter can cause received video to stutter or display jerky movements and make audio sound choppy or distorted to remote viewers.

Quality Limitations

There are two main limitations that can severely impact the outgoing media quality transmitted from a local peer to remote peers:

CPU Limitations

Insufficient CPU cores or processing power can cause delays in encoding and transmitting outgoing audio/video packets. This leads to increased latency, jitter, and potential packet loss for the streams received by remote peers.

Network Limitations

Bandwidth, throughput, or network equipment constraints can create congestion and bottlenecks specifically along the local peer's upload path. This results in higher outgoing latency, jitter, and packet loss that significantly reduces the media quality observed by remote participants.

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