You skip forward 10 minutes in a movie. Suddenly, audio and video are out of sync.
This is stream muxing latency — how the audio and video tracks are packaged together.
A properly muxed British IPTV reseller uses muxing settings that maintain sync across seeks. Keyframes are placed frequently. Audio and video chunks are aligned.
A poorly muxed service uses long keyframe intervals (10+ seconds) and unaligned chunks. Seek to any point that isn't a keyframe, and sync drifts.
I tested seeking on two services playing the same movie. Service A: seek anywhere, sync perfect. Service B: seek more than a few minutes, sync off by 0.5-2 seconds. The difference was muxing configuration.
A sync-committed British IPTV service uses keyframe intervals of 2-4 seconds, not 10. They align audio chunks with video chunks. Seek works correctly.
Here's a test you can run. Watch a movie. Skip forward 10 minutes. Check sync. Skip back 5 minutes. Check sync. If sync degrades with seeking, muxing is the issue. The careful IPTV reseller UK has tuned their muxing for seek-friendly performance.