# ECP-0117: Live Fragment Duration and Audio Unlock

Status: Draft

## Problem / context

Hosted live playback can subscribe to a local HDHomeRun stream while the visible frame stays frozen and audio stays muted. Browser inspection showed `currentTime` advancing through keyframe-spaced buffered ranges, but each range was only one microsecond long. The web wrapper also left the `<moq-watch muted>` attribute in place, so a user gesture could be overwritten back to muted.

## Decision

Publish WebTransport fMP4 with keyframe-duration fragments (`frag_keyframe`) instead of one fragment per frame, and default `wt-publish` / `nbc-wt-publish` to the non-passthrough CMAF sample path. On the hosted web player, remove the `muted` attribute and reapply unmuted state to both the wrapper and underlying video element after a user gesture.

## Consequences

- Browser MSE receives continuous segment-duration ranges instead of isolated zero-length frame ranges.
- Live playback accepts GOP-sized fragment latency, matching the current 48-frame live GOP.
- Relay subscribers receive `video0.m4s` and `audio0.m4s` media groups by default instead of catalog-only passthrough announcements.
- Audio remains gesture-gated for autoplay policy, but the gesture now actually unmutes the player.

## Alternatives considered

- Raise web jitter again. Rejected because the buffered media ranges were effectively zero-length; more latency does not turn still ranges into playable media.
- Keep passthrough mode as the default. Rejected because relay probes received only `catalog.json` while the non-passthrough sample path delivered video and audio media groups.

## Rollout / teardown

Rebuild/restart local and hosted publishers, deploy the updated web asset, and verify hosted playback by checking frame hashes over time. Teardown is restoring `WT_PUBLISH_MOVFLAGS` to `frag_every_frame`, restoring passthrough defaults to true, and restoring the prior muted wrapper behavior.