[FFmpeg-devel] [PATCH v2 00/11] fix broken CC detection and ffprobe fields (cover letter)

[Devin Heitmueller]

> Do you have an example stream recording?
> And who are those who wouldn't be following? Broadcasters?

For what it's worth, I have seen this and it can definitely happen.
It's not common though since it both technically violates the spec and
also not best practice (for example, some televisions won't show you
the option to enable captions if the caption stream isn't present at
all).  Generally it occurs when the broadcaster is doing splicing of
TS streams entirely in the compressed domain (e.g. for ad insertion),
or cases where ads or programs don't contain captions and the
encoder/transcoder isn't smart enough to generate empty caption
packets and include them in the output.

That said, I think it's very defensible to say, "We don't set the flag
saying captions are present if not detected within the probing
window".

Devin

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Devin Heitmueller, Senior Software Engineer
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