Video Calls Lag or Freeze

Calls that freeze whenever someone uploads photos, or a game that lags while a download runs, usually don’t mean the line is too slow. They mean the delay shoots up while the line is busy: bufferbloat. These steps show whether that’s it.

1. Grade the line in Speed Test

Open Speed Test and run it. Look at the bufferbloat grade under the speeds.

• A+, A or B: the delay barely changes under load. Go to step 3.
• C or worse: the delay climbs while the line is busy. That alone explains choppy calls. Note whether it rises more under download or under upload. On home connections it’s usually upload.

2. Watch the delay during a call

Start Ping on Continuous to a nearby server, such as 1.1.1.1, and leave it running through a call. If the chart jumps when the call freezes, and settles when it recovers, the line is the cause. MTR shows the same per hop, so you can see whether it starts at your router or beyond it.

3. Rule out the Wi-Fi

Calls also stutter on a crowded or weak Wi-Fi. Wi-Fi Analyzer times your router and the internet side by side: if the router itself is slow or jumpy, the Wi-Fi is the problem. A quick test is to join the call over a cable.

4. Fix it

• Turn on Smart Queue Management on the router. It may be called SQM, Smart Queue, QoS, fq_codel or cake. Set its speed limits a little below your plan, around 90%.
• Pause big uploads during calls: photo libraries, cloud backups, large file syncs.
• Use a cable, or move closer to the router if step 3 pointed at the Wi-Fi.

Run Speed Test again afterwards. The grade should improve, even if the speeds drop slightly.

Related

• Bufferbloat, Jitter and Latency.
• Wi-Fi is weak in some rooms.