[MPlayer-dev-eng] Subtitles modules

[Aurelien Jacobs]

On Sat, Dec 04, 2010 at 01:36:16AM +0100, Clément Bœsch wrote:
> On Sat, Dec 04, 2010 at 01:07:43AM +0100, Aurelien Jacobs wrote:
> > On Tue, Nov 30, 2010 at 10:41:32PM +0100, Clément Bœsch wrote:
> > > On Tue, Nov 30, 2010 at 10:17:51PM +0100, Nicolas George wrote:
> > > > Le decadi 10 frimaire, an CCXIX, Clément Bœsch a écrit :
> > > > > Hi,
> > > > > 
> > > > > subreader.c is huge file with lots of various, and I was planning to
> > > > > extract specific subtitles format functions into sub modules, just like
> > > > > libmpdemux, libmpcodecs, etc.
> > > > > 
> > > > > So first step, I'd like to just put specific format functions into
> > > > > specific files:
> > > > <...>
> > > > > If I'm not wrong the second step would be to define some instance and info
> > > > > struct just like with at least init, read, postproc, dump and close
> > > > > function.
> > > > > 
> > > > > The automatic type detection could be ported in the init function of each
> > > > > type.
> > > > > 
> > > > > Does anyone has a grudge against this, or see a big obstacle?
> > > > 
> > > > I am all for it in principle, but there may be even better: libavformat has
> > > > recently gained the capacity to decode some text subtitles format (at least
> > > > ASS and SRT): rather than working on mplayer, you may want to try to port
> > > > the subtitles decoders that mplayer has and lavf does not have to lavf, and
> > > > then entirely rely on lavf in mplayer. On of the pros of this solution is
> > > > that lavf already has all the probe/init/read infrastructure designed.
> > > > 
> > > 
> > > Indeed I saw the integration of ASS and SubRip in FFmpeg, but I only saw
> > > ASS and SubRip as muxed subtitles, so are you sure FFmpeg developers would
> > > accept support for external subtitles format such as JacoSub or SAMI?
> > 
> > Definitely yes !
> > All subtitles format are welcome in FFmpeg.
> 
> Oh? Al'right then, I'll try to submit some patches when they get ready.

Great !

> > The architecture for muxing/demuxing and for encoding/decoding is
> > already in place. It will certainly take you some more time to implement
> > proper (de)muxer and decoder in FFmpeg but I think it's definitely worth
> > it. I'm planning to add support for various subtitles format, but I have
> > only very limited free time those days so it will probably take quite
> > some time.
> > I have already support for srt, microdvd and movtext close to be ready,
> 
> There is already a support for markup in MPlayer, I suppose you're aware
> of it; maybe you can reuse it.

Yes I'm aware of it. I made an independent implementation, but I then
had a look at MPlayer's code to check if I didn't forgot to support any
kind of formatting, etc...

> What's the movtext you're talking about?

The native codec embeded in .mov files, which lavf is exporting as
CODEC_ID_MOV_TEXT.

> > just needing some polishing. So if you want to start implementing
> > some subtitles decoders, it would be more useful if you start by some
> > other formats.
> 
> OK. Well then maybe I'll start with easy ones (MPlayer sub for example, or
> VPlayer and such), and then I'll for for more complex and crazy ones such
> as JacoSub or SAMI.

Wise choice.

> > Anyway, it would be very nice to see someone else working on FFmpeg
> > text subtitle support.
> > 
> 
> Would be a great pleasure. See you soon then if I found enough time in the
> next days :)

:-)

Aurel