Live HLS: fragment objects accumulate for the whole session, and the per-second loops walk every hole #211

Severity: low

Where: chrome/player/players/hls/HLSPlayer.mjs (trackUpdated: if (!this.client.getFragment(identifier, fragment.sn)) makeFragment(...); nothing deletes entries whose sn has left the live window), chrome/player/FastStreamClient.mjs (freeFragments drops only the data of complete fragments; the store is a sparse array indexed by media sequence number, and for (let i = 0; i < fragments.length; i++) loops run every second)

What happens

A stream watched for hours keeps one HLSFragment plus the hls.js Fragment (stats, elementary-stream info, key references) per segment ever listed: about 1-2 KB x 1,800 per hour for 2 s segments, and the per-second loops grow linearly; a 24 h session is tens of MB and millions of empty iterations per tick.

Suggested fix

In trackUpdated, after walking levelDetails.fragments, delete store entries with sn < levelDetails.fragments[0].sn - keepBehind (calling freeFragment first), or switch the per-level store to a Map keyed by sn and iterate its values.

Confidence: high on the growth; medium on practical impact.

From a line-by-line code review of the tree at 41363fd (2026-10-02). Each claim above was checked against the source before filing; the reproduction steps and line references are as of that commit.

Generated by Claude Code