TASK 32·4. A plain MP4 keeps its index (moov) at the end, so a power cut or a killed process left the entire recording unreadable even though every video byte was on disk. The record block now carries `-movflags +frag_keyframe+empty_moov+default_base_moof`: index first, a playable fragment flushed at every keyframe, so an interrupted take plays to the last fragment. Record block only — the FLV stream output has no index and never gets the flags. Rename-on-stop is untouched. Test: `Args_RecordBlock_IsFragmentedMp4_SoACrashKeepsTheFile` asserts the flags on the record block and their absence from the streaming block. Not yet proven on a real interrupted take (kill ffmpeg mid-recording, play the result); the args test is by construction. Docs: task-32 slice 4 ticked with that caveat, TASKS row, output.md record note, HANDOFF. verify.sh: 550 passed (mouse-injection test excluded, desktop in use), 0 warnings.
47 lines
3.5 KiB
Markdown
47 lines
3.5 KiB
Markdown
# TASK 32 — Stream resilience (queued 2026-09-01 — merges the orphaned TASK 2 resume clause into the pills/signs architecture)
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> Catalog: [`TASKS.md`](../TASKS.md) — status and requirements live here.
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**Goal:** a dropped stream heals itself when physically possible, tells the truth when it isn't, and
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gets the creator back on air in one click. The ON-AIR sign + primary button in the top bar are the
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surface — they already mean "reality" (pills = intent, lights = reality, TASK 18/30); reality just
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isn't two-state. Resumption of a completed broadcast is explicitly **out of scope** (impossible via
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the API — creator ruling 2026-09-01): no lying in the copy.
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**Slices (one integration test each, in order):**
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1. ☐ **Blip retry** — app-side encoder restart: push dies while live (ProcessFailed / stdin
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backpressure death) → bounded-backoff relaunch (2s/5s/10s, N attempts) against the cached
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constant reusable-stream ingest URL. Success = push running again while the broadcast is still
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live; viewers never know. Fixes the map's stale "ffmpeg does reconnect" claim (corrected
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2026-09-01: reconnect flags are input-side only). Test: fake process fails once then starts →
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pump recovers without surfacing to the VM.
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2. ☐ **Measured grace + the sign** — while the push is dead, escalate the existing health poll
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(30s → ~5s). ON-AIR dot goes **amber "RECONNECTING"** with a mm:ss countdown to the observed
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YouTube cutoff; the grace length is a **measured, pinned constant** — probe it on a real private
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test stream, cite the observation (spin-guard rule; do NOT invent a number). Poll reports the
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broadcast `complete` → dot **red "OFF AIR"**, primary button relabels **"● Back on air"** and
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pulses. Test: fake status provider drives the dot through live → reconnecting → cut-off.
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3. ☐ **One-click Back on air** — the relabeled button fires the existing go-live path with saved
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`Broadcast.*` + cached stream, dialog skipped: new broadcast, new VOD (accepted cost, stated
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in-product). Test: seeded saved form + fake stream service → click creates + pushes, no dialog.
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4. ✅ **Crash-safe recording** (shipped 2026-11-05) — fragmented MP4 on the record block (`-movflags
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frag_keyframe+empty_moov+default_base_moof`): plain MP4's trailing moov atom means a power loss
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kills the WHOLE file. Rename-on-stop unchanged. Closes the TASK 18 "MKV as an option" design-note
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remnant (fragmented MP4 chosen over MKV: single container, YouTube-upload-native — verify player/
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editor tolerance, cite the research). Test: `Args_RecordBlock_IsFragmentedMp4_SoACrashKeepsTheFile` — the flags are on the record block and
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absent from the streaming block. Verified by construction only: the file still needs one real
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interrupted-take check on Windows (kill ffmpeg mid-recording, play the result).
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5. ☐ **Pre-flight** — before broadcast insert, one TCP probe to the ingest host:1935 (~2s timeout).
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Unreachable → Error toast, no insert, no ghost broadcast ("check VPN/network"). The "forgot the
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VPN" story, solved as prevention instead of recovery. Test: fake probe failure aborts go-live before any API call.
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### Design decisions
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- **The sign is the status, the button is the action** — no new chrome, no log lines, no spinners.
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- **Honest windows:** countdown = observed grace; at zero we say OFF AIR, we don't pretend to reconnect.
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- **Why us > incumbents:** constant reusable stream + persisted form make retry/restart cheap; OBS
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shows a reconnecting log line and Streamlabs silently dies.
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