[FFmpeg-trac] #11462(undetermined:new): Cannot embed .scc file into .mp4 using -c:s copy

FFmpeg trac at avcodec.org
Mon Feb 10 06:17:17 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:13 softworkz]:
 > > By the way, I believe the frame rate dependency of captions data is
 solely related to the time code that specifies which frame to embed the
 data in.  All that would be required to embed separate frame rates would
 be a calculation that would translate and align the two time codes without
 discarding data.  608 captions data simply acts on the frame it is
 embedded in not at a seperate specific time.
 >
 > The spec mandates a continuous (DTVCC) stream of data. It must not be
 on/off (sometimes there, sometimes not).

 That is what padding is for in the stream.  If you look at .scc files I
 provided from premiere pro or caption maker in a text editor you will
 notice that not every frame time code is listed in the file.  It is
 obviously necissary to insert the padding code 8080 into any frame slots
 that are not present in the source.  On the other hand if the source has
 anything other than 8080 on a particular frame, it needs passed on the
 next frame and the next instance of 8080 would get skipped.
-- 
Ticket URL: <https://trac.ffmpeg.org/ticket/11462#comment:14>
FFmpeg <https://ffmpeg.org>
FFmpeg issue tracker


More information about the FFmpeg-trac mailing list