23 October 2026

Ignore the Start-of-Programme timecode of an STL subtitle source

New ignore_stl_tcp closed captions parameter for the 436m mux type. When set to yes, the Start-of-Programme timecode (TCP) stored in the header of an EBU STL subtitle file is ignored, and the timecode of every subtitle is kept as is and aligned to the output timecode track. Use it for STL files whose TCP may be set, blank or 00:00:00:00 from one delivery to the next, so that all of them are muxed the same way.

<format>
    <output>mxf_op1a</output>
    <closed_captions>
        <source>[CCSource]</source>
        <mux_type>436m</mux_type>
        <page>[Page]</page>
        <ignore_stl_tcp>[yes|no]</ignore_stl_tcp>
    </closed_captions>
    <!-- format parameters -->
</format>

{
  "format": {
    "output": "mxf_op1a",
    "closed_captions": [
      {
        "source": "[CCSource]",
        "mux_type": "436m",
        "page": "[Page]",
        "ignore_stl_tcp": "[yes|no]"
      }
    ]
    // format parameters
  }
}

Parameter	Description	Allowed Values	Default Value
ignore_stl_tcp	Ignore the Start-of-Programme timecode of an EBU STL source and keep the subtitle timecodes as is. Applies to the `436m` mux type only. Not meant to be combined with `add_source_offset`.	yes, no	no