[FFmpeg-devel] [PATCH] Move stream_options to avformat

[wm4]

On Sun, 25 Jan 2015 13:39:10 +0100
Michael Niedermayer <michaelni at gmx.at> wrote:

> On Sun, Jan 25, 2015 at 01:18:31PM +0100, Michael Niedermayer wrote:
> > On Sun, Jan 25, 2015 at 12:15:40PM +0100, Reimar Döffinger wrote:
> > > On 25.01.2015, at 03:08, Michael Niedermayer <michaelni at gmx.at> wrote:
> > > > On Sun, Jan 25, 2015 at 02:31:33AM +0100, wm4 wrote:
> > > >> 
> > > >>>> 
> > > >>>> As an experienced API user, I don't have the slightest clue what I'd do
> > > >>>> with this API, or where to find information about it.
> > > >>> 
> > > >>> the primary goal is to remove duplicated disposition type tables,
> > > >>> which needs one of the tables to be public first
> > > >>> 
> > > >>> [...]
> > > >> 
> > > >> And this is the most awkward way you could find to do this?
> > > > 
> > > > No, i could certainly find a more akward way, if people prefer
> > > > 
> > > > this is just the way that would be a big step towards consistent
> > > > and simple access to the structs
> > > > All public structs use AVClass and AVOptions to allow applications
> > > > to extract/enumerate fields except a few like AVStream
> > > > this patch would add these AVClass & AVOption for AVStream, its
> > > > indeed not populated for all fields and AVStream doesnt have a
> > > > AVClass as its first field due to ABI. But its a step toward it
> > > > 
> > > > Would people prefer that each field in AVStream has a custom and
> > > > different way to access it, as long as it looks simpler when looked
> > > > at in isolation ?
> > > 
> > > Sorry if it's useless of me to only state some obvious questions, but:
> > > I think it's clear we all want a simple, obvious and consistent API :)
> > > If it's a bit messy, might there be a point in holding off a bit so we aren't stuck with something complicated?
> > > Could possibly another approach after a major bump be nicer?
> > > Or maybe better documentation/examples?
> > 
> > > I think this started with a valid complaint/concern but unfortunately no better alternative, could we stick to considering that instead of going over to agressive rhethoric?
> > 
> > absolutley
> > i would strongly prefer if others could take this over, my interrest
> > was just in the technical side and i wanted to move AVStream to
> > the same system we use for all other structs. As well as fixing the
> > quite valid issue nicolas had raised with the duplicated tables.
> > I am quite surprised that others dont see this as a clear and
> > uncontroversal step, there really are just
> > 1. If we want AVStream to be consistent with other structs, that means
> >    AVOption & AVClass. And this patch is a step toward it, one could
> >    make a bigger or smaller step but its then either more or less
> >    code not different code.
> > 2. There could be a different system be used for this field or for
> >    AVStream, this would be inconsistent
> > 3. We can implement both a system based on AVOptions/AVClass and a
> >    system without them, why would this field that noone cared about
> >    until now need this, iam not sure though
> > 4. We can leave the triplicated tables as is and hope not to forget
> >    updating them in sync
> > 
> > To me the best choice is clear, move toward the same system we use
> > elsewhere. Change that system everywhere if it could be improved
> > I see nothing controversal on this patch but others do apparently.
> > As i dont see what issue people have with this, i certainly cannot
> > help fixing the patch. But iam happy to review & approve the solution
> > that people do prefer
> 
> About the documentation & example side, i dont think this should yet
> be used from outside, its only a partial implementation of AVOption
> for AVStream, a full implementation needs a ABI bump due to the
> first field needing to be a AVClass
> 
> [...]
> 

How is it even consistent with "other structs"? Doesn't it just resolve
flags? Resolving flags with a complicated AVOption contraption (which
every user has to understand and duplicate) doesn't seem like a good
choice to me at all. I hear about API users fighting with the basics of
the FFmpeg API because it's so weird and complicated; seeing patches
like this just feel like a bad joke in contrast.

What's wrong with:

    int av_parse_disposition_flags(const char *s);

?