Slates, Bars, and Tone on Agency Masters
Social files skip leader. Agency and broadcast still want eight seconds of bars and tone, a 2-pop, and a slate listing job, version, LUFS, and duration.
The first eight seconds of an agency master are not the commercial. They are the calibration and the paperwork, and a traffic department that cannot identify the file without opening it will bounce the delivery before anyone watches the spot.
Social files skip all of this, for a good reason: the first frame of the file is the first frame the viewer sees. Agency and broadcast clients still want leader. Shipping the social file to the agency is how you end up on a revision for "missing bars" on a job you thought was done.
Why leader still exists
Bars and tone are a known reference, not decoration. SMPTE color bars (the HD pattern is specified in SMPTE RP 219) give a colorist or an ingest operator seven color patches and a set of pluge and black-level cues they can match against a monitor that is already aligned. A 1 kHz tone on the same eight seconds gives the audio operator a level they can set a meter to before the programme starts.
None of that is useful on TikTok. It is useful on a satellite path, a broadcast server, or an agency review that still opens ProRes in a bay. The client's delivery spec is the document that decides which world you are in. If they did not send one, ask before you print. Do not guess from the last job.
Prime Video's own Video Central spec, updated 31 May 2026, is the other pole: content must be trimmed to programme material only, and "bars and tone, test patterns, production slates, textless material" are listed as things to remove before delivery. A streamer mezzanine and an agency broadcast master are not the same file with different filenames.
The eight-second layout
This is a working commercial layout, not a law. If the spec writes a different duration, the spec wins. When it writes nothing, this is what most US and UK agency traffic still expect to see in front of a spot.
Put first frame of action at 01:00:00:00 so the programme math is boring:
| Timecode | Picture | Sound |
|---|---|---|
00:59:50:00 for 8 seconds |
SMPTE color bars (RP 219 on HD) | 1 kHz tone, continuous |
00:59:58:00 |
One-frame 2-pop: a visual flash or the digit "2" | One-frame 1 kHz burst |
00:59:58:01–00:59:59:23 |
Black | Silence |
01:00:00:00 |
First frame of action | Programme |
| Two seconds after last frame of action | Optional tail pop, same one-frame flash + tone | Same burst |
Eight seconds of bars run from 00:59:50:00 to 00:59:58:00. The 2-pop sits on 00:59:58:00, which is two seconds before first frame of action. That is the whole point of a 2-pop: anyone downstream can line picture to sound on a single frame without watching the spot.
Tone level is not universal. A common US digital alignment is −20 dBFS. EBU alignment tone is −18 dBFS. Write which one you used on the slate. Do not mix them in the same delivery batch.
The slate itself can sit on the bars (text over the pattern) or on a card in the black after the bars and before the 2-pop. Pick one, and keep it for the whole job. A slate that replaces the 2-pop is a fail, because you just removed the only sync mark on the file.
A 30-second spot with this leader is 40 seconds on disk: 8 seconds of bars, 2 seconds of 2-pop and black, 30 seconds of programme. If you also add a tail pop two seconds after last frame, the file is longer still. The duration you print on the slate is the programme duration, 00:30:00 or whatever the cut is, not the file duration. Traffic that books a :30 and receives a :40 without a slate explaining the extra ten seconds will bounce it.
What the slate has to say
The slate is the only metadata that survives a download, a rename, and a reviewer who is not looking at your email. Keep it large, high-contrast, and on for long enough to read. These fields earn their pixels:
| Field | Example | Why |
|---|---|---|
| Client | Northwind Coffee | Who paid |
| Job / ISCI or Ad-ID | NWC-2026-09-UK-30 |
What traffic files against |
| Title | Morning window :30 | Human name |
| Version | UK_EN_TEXTED_v03 |
So final2 stops happening |
| Duration | 00:00:30:00 |
Programme only |
| Frame rate | 25 fps | 24 fps clips on a 25 fps timeline is a real fail |
| Audio | 2.0, 48 kHz | Channel count, not a vibe |
| Loudness | −23.0 LUFS, −1.0 dBTP, EBU R 128 | The published target, not a forum number |
| Date | 2026-08-21 | Which print |
| Checksum | MD5, first eight hex chars | Enough to confirm they opened the right file |
Asset naming should match the slate. If the file is NWC-2026-09-UK-30_UK_EN_TEXTED_v03.mov and the slate says v02, ingest will not guess which one is true.
Do not put a URL, a QR code, or a joke on the slate. Do not put the whole script. Do not animate it. The person reading it is paused on one frame.
When to omit it
Omit leader when the first frame of the file will be shown to a person who did not ask for a master.
- Social and in-feed ads. TikTok, Reels, Shorts, most paid social placements. The viewer would see bars. The UGC delivery spec wants a clean master and a captioned master, not a broadcast leader.
- Streamer mezzanines that say so. Prime Video Video Central, 31 May 2026: strip bars, tone, slates, and textless before delivery. Other platforms publish their own ingest docs. Read them. Do not reuse the agency export.
- Client review links. A share link is for watching the cut. Leader wastes the first eight seconds of every comment cycle. Send the programme-only review file, and keep the leadered master for the traffic drop.
Keep leader when the file will be ingested by a broadcast server, an agency traffic folder, or a QC house that still aligns bars. If you are unsure, send two files: *_leader.mov and *_program.mov. One extra export is cheaper than a bounce.
Building the leader in Versely is possible but clumsy, because the editor is a programme timeline, not a broadcast origination bay. Generate or finish the spot, then add bars, slate, and 2-pop in the NLE you print from, on a sequence that starts at 00:59:50:00. Use the Versely video editor for the programme, and hand the clips to that editor cleanly with one frame rate and a shot log. Do not generate bars with a video model. You want a mathematically correct RP 219 pattern and a clean sine, not an AI impression of color bars.
FAQ
Does every country want eight seconds?
No. Eight seconds is a working default for agency commercials when the spec is silent. Some broadcast specs want a minute of bars. Some want a countdown clock. Some want no leader at all. Read the spec you were sent. If you were not sent one, put eight seconds of bars, a 2-pop at two seconds before action, and a slate that states duration, version, and LUFS, then ask traffic if they want it stripped.
Can the 2-pop be a beep in the clear with no picture?
It can, and it is a worse 2-pop. The value of the mark is that picture and sound share one frame. A beep with no flash still lets you align audio; it does not tell you whether the video stream is offset from the audio stream. Put a one-frame white (or a "2") on that same frame.
What loudness number goes on the slate?
The one you measured on the exported programme, against the standard you mixed to. For broadcast, that is EBU R 128 at −23.0 LUFS and −1 dBTP unless the spec names ATSC A/85 or something else. Do not write "−14 LUFS" on an agency slate because a YouTube forum said so. Do not write a number you measured on the timeline before export.
Why not leave leader on the social cut "just in case"?
Because the social cut is watched from frame zero. Bars become the hook. Platforms that autoplay in-feed will serve eight seconds of a test pattern to a media buyer. Prime Video will reject the file for having leader at all. Leader is a destination choice, like aspect ratio. Print it onto the agency master and leave it off everything a human is supposed to watch cold.