[FFmpeg-trac] #11462(undetermined:new): Cannot embed .scc file into .mp4 using -c:s copy
FFmpeg
trac at avcodec.org
Mon Feb 10 06:46:17 EET 2025
#11462: Cannot embed .scc file into .mp4 using -c:s copy
-------------------------------------+-------------------------------------
Reporter: Zach | Owner: (none)
Type: enhancement | Status: new
Priority: important | Component:
| undetermined
Version: git-master | Resolution:
Keywords: | Blocked By:
Blocking: | Reproduced by developer: 0
Analyzed by developer: 0 |
-------------------------------------+-------------------------------------
Comment (by Zach):
Replying to [comment:15 softworkz]:
> > That is what padding is for in the stream.
>
> And when there's no gap? How do you know at which points you can add
padding data?
With an .scc file as an input you would see something like this if padding
can be added.
{{{
00:00:02:04 942c
00:00:02:07 942f
}}}
is equivalent to the following in an .scc file.
{{{
00:00:02:04 942c 8080 8080 942f
}}}
Including too many frame time codes and not organizing according to start
and end codes causes compatibility issues with other software. My
understanding is that each frame gets one of those 4 digit hex codes. The
first code goes on the frame that matches the timecode for a line, and
each subsequent code goes on the following frame. When the particular
caption message is complete another line is started with the next time
code that captions commands are wished for. If there is a frame gap
between the last command of the previous line and the next listed time
code, the captions embedder is responsible for repeating 8080 until the
timecode listed next in the .scc file.
This understanding was derived from the documents listed under #11461.
--
Ticket URL: <https://trac.ffmpeg.org/ticket/11462#comment:16>
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