Variable-frame-rate video does not give every frame the same duration. Playback follows timestamps rather than assuming a single fixed interval. This can suit screen recordings and other changing material, but editing tools and players must handle the timing correctly to maintain smooth motion and synchronised sound.
Distinguish timing from slow delivery
A variable frame rate is a property of the media’s timestamps. It is not the same as a network connection delivering packets unevenly. A player can buffer irregular network arrivals and still present a regular timeline; conversely, a locally stored file can contain intentionally varying frame durations.
Use a sustained comparison
If a recording drifts out of sync, compare playback from the beginning with playback after a seek. Note whether the offset grows continuously or stays constant. Growing drift suggests a timing interpretation problem more than a simple fixed audio-delay setting, though other causes should still be considered.
Avoid blind frame-rate conversion
Converting to a constant frame rate can help an editing workflow, but it may duplicate or discard frames and requires proper handling of audio timing. Keep the original file and use a trusted tool with documented settings. For a live subscription stream, report the symptom rather than attempting to rewrite protected or private source URLs.
