[FFmpeg-devel] [PATCH]Basic XSUB encoder (take 2)

Björn Axelsson gecko
Tue Feb 3 10:25:03 CET 2009

On Mon, 2 Feb 2009, Diego Biurrun wrote:

> On Mon, Feb 02, 2009 at 10:55:05PM +0100, Bj?rn Axelsson wrote:
> > On Sun, 1 Feb 2009, Bj?rn Axelsson wrote:


> > --- doc/general.texi.orig	2009-02-02 22:38:39.000000000 +0100
> > +++ doc/general.texi	2009-02-02 22:41:11.000000000 +0100
> > @@ -455,7 +455,7 @@
> >  @item ASS/SSA      @tab X @tab X
> >  @item DVB          @tab X @tab X @tab X @tab X @tab X
> >  @item DVD          @tab X @tab X @tab X @tab X @tab X
> > - at item XSUB         @tab   @tab   @tab   @tab X @tab
> > + at item XSUB         @tab X @tab X @tab X @tab X @tab X
> You implemented an encoder, a muxer, a demuxer and a renderer?
> Note that I continue confused about the inner workings of the subtitle
> system, so it is a sincere question.

The more I think about that table, the more confused I get...

Are the muxing/demuxing columns for stand-alone (de)muxers, like
libavformat/assdec.c which can handle .ass files, or for muxing in other
containers such as mkv, avi etc?

Also, is the rendering column for rendering to bitmaps (e.g. render
text-based .ass subtitles to bitmaps for displaying) or for actual
rendering on the display, like what ffplay does with existing bitmaps?
In any case, XSUB is on par with DVB and DVD here, and if they support
"rendering" then XSUB does that too.
That addition should have been in a separate patch, and I'll prepare one
later if no one beats me to it.

My XSUB patch only adds encoding, and muxing into .avi containers.

ffmpeg currently supports XSUB decoding, demuxing (at least from avi)
and displaying.

I have also have experimental ASS/SSA subtitle decoder and renderer
implementations and a subtitle embedding avfilter which I'll submit for
RFC shortly.

Bj?rn Axelsson

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