[FFmpeg-devel] [Sponsored work] ASCII Text subtitles in DVB subtitles
andrey.krieger.utkin at gmail.com
Sun Jan 12 21:59:02 CET 2014
2014/1/12 Sylvain <sylvain at lahiette.com>:
> Thanks for you response.
> In fact it is possible to send text subtitles in EN 300 743, in
> addition of bitmap subtitles. The documents states that transfering
> text-only strings shall be negotiated between the broadcaster and the
> set-top-box manufacturer, as they need to agree on the font used on
> the decoder side (at least). See page 26 of ETSI EN 300 743 V1.2.1,
> field "object_coded_method". .
There's indeed something looking like text info, but not exactly usual
character_code (it is 16 bits each - my remark): Specifies a character
through its index number in the character table identified in the
subtitle_descriptor. Each reference to the character table is counted
as a separate character code, even if the resulting
character is non spacing. For instance floating accents are counted as
separate character codes.
Floating accents as separate character codes - looks unusual for any
encoding i know.
How exactly the character table should be defined in
subtitle_descriptor is not defined in the doc, and anywhere else.
So this looks to be left implementation specific, although i am not sure yet.
In such case i think it is not probable that a patch for such feature
could be included into ffmpeg mainstream. But anything is possible in
> In fact, i am searching a way to push TXT-subtiles, as well as bitmap
> subtiltes at the same time. Hence my request. I did not check for dvb-
> teletext and i will look into it to see if it fit my needs.
Please check it, it seems more usable way to move on.
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