Jitter

When watching online videos or having video meeting calls with many people, you may experience lip sync, choppy audio, and stuttering problems. In particular, when some video call participants speak, their lips may not sync with the audio you hear. One of the probable causes of these frustrating group call issues is Jitter. Apart from the call-related issues mentioned above, the existence of Jitter can affect many aspects of VoIP applications.

What is Jitter?

Jitter is a network effect affecting media quality due to possible causes like poor bandwidth, data loss, and other conditions. The higher the jitter, the lower the media quality. In typical network conditions, the order in which a sender transfers packets should be the same at the receiver's end. Due to jitter and other network conditions like stuttering, that is only sometimes the case. Jitter can affect data reception in different ways, such as: 

• Receiving data in an order different from the sent order.
• Receiving data at an interval different from the interval at which the data were sent as illustrated in the diagram below.

• Late arrival of packets.
• Failure to deliver packets.

In the case of audio and video calling, jitter can cause desynchronization and quality reduction in calls. Jitter in VoIP applications can be minimized through adjusting bitrates, jitter buffers, and synchronization of audio/video frames.

How does Jitter Affect VoIP Calls?

The presence of Jitter in VoIP applications can affect both audio and video as follows.

Voice Calls

• Choppy sound: Jitter can cause distorted or delayed voices when people speak. 
• Disconnected audio: Jitter can cause audio to drop anytime when people are talking. 
• Sound reflection: When people talk, their voices are heard back with a delay known as echo.

Video Calls

• Dropped video frames: The existence of a Jitter can cause the order in which video frames arrive at the recipient to change. The out-of-order appearance of the video frames can produce a jerky video experience. 
• A jitter can sometimes freeze the video frames and make the video pixelated.

How can Jitter be Prevented in VoIP Calls?

Several ways exist to minimize Jitter in a network and VoIP applications. The most common ones involve:

• Jitter Buffers: Sometimes, data packets may arrive out of order at a target. Using Jitter Buffers helps to put these out-of-order packets in the correct order and smooth them to reduce Jitter. 
• Quality of Service: A network mechanism like Quality of Service can be used to prioritize voice and video packets over other network traffic, such as downloading or browsing.
• Traffic Shaping: A network technology like Traffic Shaping can be used to manage the flow of data packets and bandwidth distribution to prevent congestion in the network.
• Network performance improvement: Network optimization techniques, like routing protocol enhancement and congestion prevention, can be used to minimize Jitter. 
• Bandwidth usage monitoring: Bandwidth management is crucial in preventing Jitter. For example, bandwidth management mechanisms for allocation and prioritization can be used to avoid delays of packets in the network.

Frequently Asked Questions