[FFmpeg-devel] [PATCH] lavf: add ffprobe demuxer

[Stefano Sabatini]

On date Thursday 2016-09-29 21:55:11 +0200, wm4 encoded:
> On Thu, 29 Sep 2016 01:21:01 +0200
> Stefano Sabatini <stefasab at gmail.com> wrote:
> 
> > On date Monday 2016-09-26 18:55:47 +0200, wm4 encoded:
> > > On Sun, 25 Sep 2016 19:32:37 +0200
> > > Stefano Sabatini <stefasab at gmail.com> wrote:  
> > [...]
> > > > > > My use case: I need to build a data stream with scripting/manual
> > > > > > editing. Since I don't want to have to rely on a binary format (which
> > > > > > is not ideal for that use case) I needed a format simple enough to be
> > > > > > written and analysed without special tools, but with a simple text
> > > > > > editor.    
> > > > > 
> > > > > I still don't get it. Your description makes me think of something like
> > > > > EDL, but that doesn't seem to have anything to do with it.    
> > > > 
> > > > EDL as "Edit Decision List"? No I don't think this is related at
> > > > all.
> > > > 
> > > > Suppose you want to inject a data stream, you have the data and you
> > > > know where to insert it given its PTS. With this muxer you can
> > > > handcraft a textual file in the ffprobe_default format and use ffmpeg
> > > > to inject the new data stream.  
> > >   
> > 
> > > What's a "data stream"?  
> > 
> > A stream consisting of generic data, that is a stream with type
> > AV_MEDIA_TYPE_DATA.
> > 
> > > Inject into what?  
> > 
> > Interleave the stream with other media streams (audio, video,
> > etc.). This can be done via remuxing (no need for transcoding).
> > 
> > > And why?  
> > 
> > Data stream could be used to insert custom information for
> > post-processing (e.g. they might contain advertising information).
> 
> This seems like a rather special use case. Why does it have a demuxer,
> and can't be in your own C code using libavcodec/libavformat?
> 

> In addition, I think using the ffprobe "format" is an overcomplication,
> and will justify adding even more stuff to the demuxer, until it's a
> similarily complex mess like the ffm demuxer/muxer.

I'm aware of the issue. OTOH I think the feature per-se is useful, at
least for the two mentioned use cases (debugging - especially if
coupled with a corresponding muxer), and data streams (generated by
script) injection, since it relies on a textual format easily
scriptable and editable by hand.

I thus leave the choice to the community. I guess this will require a
vote if we cannot find an agreement.

Latest patch in attachment with ffprobe demuxer disabled by default,
and extended documentation. (I'm also attaching the ff_get_line2 patch
which is used by this new patch).
-- 
FFmpeg = Fierce Frenzy Magnificient Plastic Explosive Gadget
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