[FFmpeg-user] bitmap-subtitle in stream

Carl Eugen Hoyos ceffmpeg at gmail.com
Thu Jun 21 13:09:31 EEST 2018

2018-06-21 11:44 GMT+02:00, Thomas Schmiedl <thomas.schmiedl at web.de>:
> Am 16.06.2018 um 19:03 schrieb Carl Eugen Hoyos:
>> 2018-06-16 18:56 GMT+02:00, Thomas Schmiedl <thomas.schmiedl at web.de>:
>>> I use ffmpeg on a router to restream a DASH-stream
>>> (https://live.idnes.cz/slow/slowtv7_720p/manifest.mpd) to a local
>>> htdocs-folder as HLS on the router. The media-server xupnpd2
>>> reads the HLS and transfers it to the TV.
>>> On the DASH-stream website
>>> https://slowtv.playtvak.cz/prave-ted-mazaci-tramvaj-jede-prahou-d73-/mazaci-tramvaj.aspx?c=A150908_111659_mazaci-tramvaj_plap
>>> is a map with the actual position of the tram. The router is to slow
>>> for re-encoding using the video-filter "overlay".
>>> Is it possible to integrate a bitmap-based subtitle in the generated
>>> HLS-stream containing an actual map-image (e.g.
>>> http://staticmap.openstreetmap.de/staticmap.php?center=50.05619,14.43873&zoom=15&size=800x300&maptype=mapnik&markers=50.05619,14.43873,ol-marker)
>>> without re-encoding?
>> In theory, you could provide subtitles but all formats are palettized
>> and creating a palettized image also takes time. In any case, you
>> would have to implement this programmatically.
> Could someone provide a workflow how to do that programmatically. Until
> now I have only worked with the ffmpeg-application in combination with
> xupnpd2 mediaserver.

Sorry, this is not something a beginner will be able to implement.
The overlay filter is the only way to do this currently, its performance
has been increased lately but that does not necessarily mean it will
work on slow hardware.

Carl Eugen

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