In this guide
Compare the two range setsCheck the requested and resulting positionReport the dependency created by the jumpDragging a progress bar to a distant point can work even when the device has not downloaded that part of the programme. The player may request the needed media only after the seek. A full-looking seek bar therefore does not prove offline availability or local completion.
This distinction helps explain why an earlier section plays while a later jump fails, and why a live position offered before a long pause may no longer work afterward.
Compare the two range sets
For a browser player under your control, inspect current buffered and seekable ranges separately. An original hypothetical video reports buffered [0, 120] seconds and seekable [0, 3600] seconds. At minute thirty, the player may need a fresh request even though that position lies within the seekable hour.
If the jump fails, capture the new request and player error. The already buffered opening two minutes can keep playing without proving that later delivery is healthy. This is a useful contrast rather than a contradiction.
Check the requested and resulting position
Record where the user attempted to seek and where playback actually resumed. Media indexing and random-access points can affect the exact result. A jump that lands close to the requested time is a different symptom from one that returns to live or produces an HTTP failure.
For live media, refresh the seekable view before drawing a conclusion about an old position. A moving window may exclude it, and replay availability needs its own documented support. Do not infer unlimited time-shifting from the presence of a pause or scrub control.
Report the dependency created by the jump
A precise report states the buffered interval before the action, the seekable interval, the intended position and the request outcome after the jump. If the player sends a byte-range request, include redacted range metadata rather than calling a 206 response a partial failure. If the source is segmented, identify the newly selected media resource.
Avoid clearing caches before preserving this distinction. A cache reset changes what is local and may erase the contrast between a working buffered section and a failed remote request. The narrow question is whether the player could obtain and interpret the media needed at the new position, not whether the entire video had previously been downloaded.
- Record buffered and seekable ranges before the jump.
- Note requested and actual presentation positions.
- Identify any new range or segment request.
- Classify its result separately from the already buffered section.