[FFmpeg-devel] SDR lib comments

[Michael Niedermayer]

On Thu, Sep 28, 2023 at 05:07:17PM -0400, Vittorio Giovara wrote:
> On Thu, Sep 28, 2023 at 3:28 PM Michael Niedermayer <michael at niedermayer.cc>
> wrote:
> 
> > On Thu, Sep 28, 2023 at 12:28:22PM +0200, Anton Khirnov wrote:
> > > Quoting Michael Niedermayer (2023-09-23 18:43:44)
> > > > Is a seperate library really the right choice for SDR in FFmpeg at
> > this stage ?
> > > >
> > > > Also code can always be moved into an seperate library
> > >
> > > we've had postproc in the tree for ages, nobody maintains it or
> > > cares about it, yet it seems impossible to get rid of it.
> >
> > what maintaince does it need ?
> >
> 
> making sure that the library builds on all supported system, doesn't have
> security holes, etc

is it failing to build ?
i would expect if it fails to build to be contacted about that. Or well
if not that people would not expect it to be fixed by me.

are there security holes ?
If so i would expect them to be reported to ffmpeg-security or me or
something like that.


> or for packagers to bundle the library
> 
> 
> > libpostproc implements part of ISO/IEC 14496-2
> > (that is the spec for an MPEG-4 ASP decoder)
> >
> 
> We're going a bit off topic, but you're referring to something preceding
> H264 which means is something older than 20 years -- while old formats
> surely need to be supported against digital obsolescence, the
> code:functionality ratio is certainly not worth it (who uses ASP
> nowadays?),

There is substantial amounts of existing material in ASP


[...]

> 
> 
> > I have too many other things to work on to do a big refactoring of it
> > but if there are small bugs in it or questions about it i can look into
> > them
> >
> 
> I think the main reason libpostproc was mentioned is that we don't want a
> repeat of the history for SDR - so far you're only developer expressing

SDR currently is completely self contained in a input device/demuxer.
Thats the very opposite of libpostproc which is a bit of video filtering
a bit of mpeg4 ASP and neither in libavfilter (which did not exist when libpostproc
was created) nor libavcodec

The main obstacle to cleanup libpostproc is probably the old style interleaved
SIMD code. Again this has no parallel to SDR

thx

[...]

-- 
Michael     GnuPG fingerprint: 9FF2128B147EF6730BADF133611EC787040B0FAB

Everything should be made as simple as possible, but not simpler.
-- Albert Einstein
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