Ad Break Timing and Cue Points: SCTE-35 for FAST Operators

Created by Andrew Baritz, Modified on Wed, 7 Jan at 12:08 PM by Andrew Baritz

Ad Break Timing and Cue Points: SCTE-35 for FAST Operators

At a glance
If your stream does not signal breaks correctly, SSAI cannot safely insert ads, and platforms may ignore or reject your breaks. Most “we have demand but no revenue” incidents trace back to bad break signaling or break timing.

Who this is for

FAST operators defining ad load and break placement
Playout/encoding teams inserting cue markers
Ad ops teams troubleshooting low fill or zero impressions

What operators should know (non-technical)

An “ad break” is not just a creative decision. It must be machine-readable.
SCTE-35 is the standard way to mark “break starts now” and “break ends now.”
Consistency matters: if your breaks wander (e.g., 78 seconds instead of 90), you get mismatch errors and lost fill.

Key terms

SCTE-35: A cueing message standard used to signal splice points for ad insertion and program control.
Cue-in: Marker indicating the start of a break.
Cue-out: Marker indicating the end of a break (or a duration declared in the cue-in).
Splice point: The exact frame/segment boundary where a break begins or ends.

Responsibility boundaries

Task	You (operator / engineering)	SSAI / platform
Insert SCTE-35 markers	Yes	No
Detect markers and create ad opportunities	Config + validation	Yes (SSAI behavior)
Enforce device/platform break rules	Align your break policy	Yes (policy enforcement varies)

Walkthrough: From cue marker to monetized pod

Playout emits SCTE-35 at a clean segment boundary (HLS/DASH segment alignment matters).
SSAI reads cue-in and opens an ad pod for a declared duration (or waits for cue-out).
SSAI requests ads sized to the pod duration (e.g., 90s pod → three 30s ads or other combinations).
SSAI stitches ads and returns a modified manifest (per viewer, in most SSAI systems).
Player downloads segments and playback proceeds without client-side ad calls.

Operational rules that keep you out of trouble

1) Standardize pod durations

Pick a small set of pod durations and stick to them.
Ensure your schedule, SCTE markers, and SSAI “pod config” all match the same policy.

2) Always close the break cleanly

If your workflow uses cue-out, missing cue-out is a top reason pods “never close” and the stream drifts.
If your workflow declares duration in cue-in, validate that the declared duration matches actual playout.

3) Align SCTE timing with segment boundaries

Bad boundary alignment can create manifest discontinuities and device playback failures.
This is where encoder settings (GOP, segment duration) and cue insertion must match.

Real-world break maps (examples)

Example 1: Episodic channel (30-min show)

00:00:00  Program start (no ads for first 120s)
00:10:30  Break 1 (90s)  [cue-in] ... [cue-out]
00:20:45  Break 2 (90s)  [cue-in] ... [cue-out]
00:29:30  Between-episode break (60s) [cue-in] ... [cue-out]

Example 2: News loop / talk block (continuous)

Break cadence: every 8–10 minutes
Pod length: 60s
Rule: never break during lower-third graphics transitions (platform QA failure risk)

Examples you can paste into tickets

Example: “SCTE-35 issue” information to request from engineering

Channel ID:
Time window (UTC):
Playback URL used:
Expected break time(s):
Observed behavior (no ads / wrong length / glitch):
Encoder settings (segment duration, GOP size):
SCTE-35 output sample (base64/hex if available):
SSAI logs around cue detection:

Example: Break policy (for programming + ad ops alignment)

Program type	Break cadence	Pod length	Max single ad
Movies	Every ~12 minutes	120 seconds	30 seconds
Episodic	2–4 breaks per episode	90 seconds	30 seconds
Short-form blocks	Between items only	60 seconds	15–30 seconds

Example: “SCTE sanity checklist” for QA

Every cue-in has a matching cue-out (or a declared duration that matches reality).
No overlapping breaks.
No breaks inside restricted zones (platform-specific).
Break start/end aligned to segment boundaries.

Troubleshooting

Problem	What to check	Quick fix
Ads never appear	Are SCTE markers present? Is SSAI configured to listen for them?	Verify cue insertion; confirm SSAI cue ingestion; inspect SSAI logs for “cue detected” events
Ads appear but break lengths are wrong	Declared duration vs actual playout	Standardize pod length; enforce creative duration; add validation on stitch output
Playback glitches at breaks	Discontinuities, segment/GOP alignment, codec changes	Align encoding ladder; keep ad creative specs compatible with content ladder

Ad Break Timing and Cue Points: SCTE-35 for FAST Operators

Ad Break Timing and Cue Points: SCTE-35 for FAST Operators

Who this is for

What operators should know (non-technical)

Key terms

Responsibility boundaries

Walkthrough: From cue marker to monetized pod

Operational rules that keep you out of trouble

1) Standardize pod durations

2) Always close the break cleanly

3) Align SCTE timing with segment boundaries

Real-world break maps (examples)

Example 1: Episodic channel (30-min show)

Example 2: News loop / talk block (continuous)

Examples you can paste into tickets

Example: “SCTE-35 issue” information to request from engineering

Example: Break policy (for programming + ad ops alignment)

Example: “SCTE sanity checklist” for QA

Troubleshooting

Sources