What it checks
Every subtitle of an EBU-STL file is measured on the bytes actually stored in the file. A subtitle whose widest row uses more cells than the profile allows produces one issue. A teletext row holds 40 cells: whatever lies beyond the 40th cell is not displayed.
Only EBU-STL files are measured: other formats have no teletext rows, so the rule never reports on them. When CueNorm converts to EBU-STL, the rule judges the generated file.
How it is measured
This is a physical measure, distinct from the editorial character count of MAX_CHARACTERS_PER_LINE.
- Every character takes one cell.
- Every teletext control code in the row also takes one cell: colour, double height, boxing. A line of 36 characters preceded by a colour code and a double-height code uses 38 cells.
- An accented letter stored as a floating diacritic plus its letter (the Polish
ąis two bytes in ISO 6937) takes one cell. - The row separator and the padding bytes take no cell.
Parameters
| Parameter | Type | Meaning |
|---|---|---|
max |
positive integer | Maximum cells per row, normally 40 |
Example
With max: 40, a row made of the white colour code, the double-height code and 40 characters is reported as A row uses 42 teletext cells (max 40).
The shared EBU-STL teletext base declares this rule as a warning: some broadcasters accept such files and fix the rows at playout. A profile requiring strict compliance declares it again with severity: error.
How to fix
- Shorten the line so that the text plus its control codes fits in 40 cells. With colour and double height, that leaves 38 characters.
- Split the line at a natural phrase boundary, within the profile's maximum number of lines.
- Apply the editorial
MAX_CHARACTERS_PER_LINElimit of the destination, which normally keeps rows within the teletext width.