[FFmpeg-devel] Status of dvdsub "forced_subs_only" patch

Nicholas Robbins nickrobbins at yahoo.com
Mon Sep 15 17:47:13 CEST 2014

Oliver Fromme wrote:

> Michael Niedermayer wrote:
> > On Sun, Jun 29, 2014 at 05:36:32PM +0200, Oliver Fromme wrote:
> > > [...]
> > > The problem with dropping rectangles in utils.c is that there
> > > might be multiple output streams.  The flag ("forced subtitles
> > > only") might be set for some output streams, but not for others.
> > > So, if we dropped some rectangles from the AVSubtitle structure
> > > in utils.c, they will be missing from other output streams that
> > > are encoded afterwards.
> > 
> > You can put the, to be kept rectangles in a new AVSubtitle struct.
> Oh, it didn't occur to me to generate an new AVSubtitle struct
> in utils.c.  Thanks for pointing that out.
> I'll give that a try and make a new patch.
> Best regards
>   Oliver

Has there been any update on this?

I would like to be able to pick out only the forced subtitles from a dvdsub track. This looks like it was my best bet. I can't find any documentation of this or figure out a useful place to put -forced_subs_only 1 in the command line:

ffmpeg -forced_subs_only 1 -i tmp.mkv  -map 0 -c:s dvdsub   out.mkv

I get ...

Codec AVOption forced_subs_only (Only show forced subtitles) specified for input file #0 (tmp.mkv) has not been used for any stream. The most likely reason is either wrong type (e.g. a video option with no video streams) or that it is a private option of some decoder which was not actually used for any stream.

tmp.mkv is just:

Stream #0:0(eng): Subtitle: dvd_subtitle, 720x480 (default)
      LANGUAGE        : eng
      ENCODER         : Lavc55.69.100 dvdsub


More information about the ffmpeg-devel mailing list