[FFmpeg-user] Add soft subtitles to YouTube Stream Now?
steven at kan.org
Wed Nov 20 16:43:00 EET 2019
> On Nov 20, 2019, at 7:11 AM, Moritz Barsnick <barsnick at gmx.net> wrote:
> On Tue, Nov 19, 2019 at 22:45:44 -0600, Steven Kan wrote:
>> What I want to do is add some captions to the video as soft
>> subtitles, e.g. my location, the present temperature, and the weather
>> forecast. I don’t have enough CPU on the Pi to burn these into the
>> video stream.
>> Is this possible in ffmpeg and with YouTube’s “stream now” feature?
> Check this page:
> YouTube currently only accepts FLV streams, and subtitles only as EIA
> 608/708 captions. As far as I can tell, ffmpeg is currently not capable
> of creating or embedding these captions.
> There's an enhancement request for muxing support:
> https://trac.ffmpeg.org/ticket/1778#comment:10 <https://trac.ffmpeg.org/ticket/1778#comment:10>
If I’m demuxing your answer correctly, the answer is “no,” at least of now. Thank for your reply; at least now I won’t spend hours trying to find a solution that doesn’t exist! That enhancement request has had no updates for 2 years :-(
EIA 608/708 caption generation appears to be non-trivial!
I did find this libcaption project:
and this page saying that the captions can be pushed via RTMP:
I know this is somewhat OT for ffmpeg, but can I push two RTMP streams to YouTube, one for the a/v, and one for the captions?
Back on-topic, given that libcaption exists, how difficult a task would it be to integrate support into ffmpeg? Is it just a matter of re-muxing the output from libcaption into the ffmpeg output stream? I’m not programmer, unfortunately, but I’m just trying to get a sense for the scope of the problem.
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