[FFmpeg-devel] [PATCH v8 12/13] avfilter/split_cc: Add split_cc filter for closed caption handling

[Andreas Rheinhardt]

Soft Works:
> 
> 
>> -----Original Message-----
>> From: ffmpeg-devel <ffmpeg-devel-bounces at ffmpeg.org> On Behalf Of Andreas
>> Rheinhardt
>> Sent: Wednesday, 22 September 2021 04:18
>> To: ffmpeg-devel at ffmpeg.org
>> Subject: Re: [FFmpeg-devel] [PATCH v8 12/13] avfilter/split_cc: Add split_cc
>> filter for closed caption handling
>>
>>> This is a good question, as to whether it is safe to assume that the
>>> filter's lifetime doesn't end before the last frame has been processed.
>>> I thought it would be?
>>
>> So the frames are supposed to be never forwarded to the user? Or is the
>> user supposed to stop using these frames after the filter's lifetime ended?
> 
> 
> The subtitle_header is global and is constant across all frames.
> A resulting media file has only a (= the) single "subtitle header".
> (it's not like a "header for each subtitle line or event").
> 

Who ensures that it is constant across all frames? What happens if one
mixes frames from two different sources? And who owns the subtitle header?

- Andreas