What your export has to say, not just look like
A broadcast master is judged by what is written inside the file, not by how it plays on your monitor. Here is what a public television master has to carry, and where an editing preset quietly writes something else.
Quality control at a distributor starts by reading the file: the wrapper, the codec, the bit rate, the chroma, the field order, the colour signalling, the timecode, the audio layout. All of that is written into the file by your export, and none of it is visible while the programme plays. A master can look perfect and fail before anyone watches a frame.
What the file has to say
| Property | What a public television master carries |
|---|---|
| Wrapper | MXF OP1a |
| Codec | XDCAM HD422 — MPEG-2 long GOP at 50 Mb/s (DNxHD 145/220/220x also accepted; ProRes 422 accepted, not preferred) |
| Raster and chroma | 1920 × 1080, 4:2:2, 8-bit |
| Frame rate and scan | 29.97, interlaced, upper field first |
| Colour | BT.709 matrix, primaries and transfer, actually signalled in the file; limited range |
| Timecode | Drop-frame, starting at 01:00:00;00, continuous, with a frame of black at head and tail |
| Audio | PCM, 48 kHz, 24-bit, in the channel layout your distributor asks for — a stereo pair, or eight channels with described video and second language in 7 and 8 |
Those values are NETA’s; another distributor will change some of them. The point is not the list, it is that each line is a statement the file makes about itself, and each one is read.
Where an editing preset gets it wrong
- A preset with the right name and the wrong insides. “XDCAM HD 1080i” can write 35 Mb/s instead of 50, or 4:2:0 instead of 4:2:2. The name of the preset is not the specification.
- Field order. Progressive material exported into an interlaced wrapper, or a lower-field-first flag on upper-field-first content. It plays fine on a computer and tears on a broadcast monitor.
- Colour left unsignalled. The picture is BT.709 but the file says nothing, so whatever reads it next has to guess — and different systems guess differently.
- Start timecode. Left at 00:00:00:00, or non-drop when the spec says drop-frame. Everything timed against it — captions above all — inherits the error.
- Audio layout. One interleaved stereo pair where the spec asks for discrete mono tracks, or 16-bit where it asks for 24.
- Re-encoding what was already correct. A finished master run through another export loses generation quality for nothing.
What to do before you send
- Read the file, not the timeline. Whatever you use, open the finished export and compare what it reports with the specification line by line.
- Check the head and the tail. A frame of black at each end, no bars, no tone, no slate unless the programme instructions ask for them.
- Confirm the running time against the distributor’s limit before the master is built, not after.
- Keep the export settings that produced an accepted master. Next episode, change nothing.
That is the part producers can do themselves, and it catches the obvious. What it does not catch is the picture and sound inside: levels out of range on one frame, a dropped or duplicated frame, clipping under music, captions over a lower third. That is what the audit is for.
Let me read the file before your distributor does
The first Delivery QC Audit is free — one free audit per production company, one file up to 60 minutes — with a written report in two business days, every item measured or checked on the picture.
See what you get first: a sample report (PDF) · the same report on a failing master (PDF)
Read next
Written by Cleared for Air. The distributor documents and the standards behind each check are listed under Resources. Your distributor’s own requirements are the ones that count; check them before you deliver. © 2026 Cleared for Air.