[FFmpeg-trac] #11462(undetermined:new): Cannot embed .scc file into .mp4 using -c:s copy
FFmpeg
trac at avcodec.org
Mon Feb 10 19:16:34 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:24 Devin Heitmueller]:
> I took a look at the actual command line provided by the OP, as well as
the code, and it does work as expected when the MP4 is created in MOV
mode.
>
> To create the file in MOV mode, specify the filename as ".mov" rather
than ".mp4". For example:
>
> ./ffmpeg -i ../../whatever.ts -i ../../AIM-2301_premiereExport.scc -map
0:v -map 0:a -map 1 -c:v copy -c:a copy -c:s copy output.mov
>
> Once you do that, it creates the output file with a caption track, and
the result is playable in Quicktime:
>
> Example output:
>
> Stream #0:7[0x8]: Subtitle: eia_608 (c608 / 0x38303663), 0 kb/s
(default)
> Metadata:
> handler_name : ClosedCaptionHandler
This would at least be easier to handle a file library than dealing with
sidecar files, but VLC does not detect that type of muxing in an mov file.
Since I use VLC for testing file quality and don't really want to move to
ffplay for that I don't think this solution is a viable option.
I also see a benefit from having the ability to combine a video stream
with a captions stream for applications such as transcoding from .mxf to
mp4 or mpegts. Many playout solutions exclusively require .mxf op1a files
with 436m captions. While I haven't investigated ffmpeg support for those
files recently and know that work has been done recently on it, that
conversion does fundamentally require integrating a separate captions
stream into the video stream and occasionally requires transcoding of
either video or audio due to container codec limitations.
Why don't we separate the discussion of the uncompressed domain solution
and the compressed domain. This ticket should really just about a
solution that can integrate a seperate captions stream from .scc, .mcc, or
mxf 436m caption track to an A/53 Part 4 or SCTE-128 DTVCC encoded stream
within the video elementary stream headed to an mp4 file. If the solution
can also work for mpegts outputs that would be great, but mpegts outputs
will require a higher degree of standards compliance due to multiple
decoder targets.
--
Ticket URL: <https://trac.ffmpeg.org/ticket/11462#comment:27>
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