[FFmpeg-devel] [PATCH] lavfi: add quirc filter

[Stefano Sabatini]

On date Wednesday 2023-12-27 21:57:19 -0300, James Almer wrote:
> On 12/27/2023 8:20 PM, Stefano Sabatini wrote:
[...]
> > > I really think this should be ported as a native filter. It's not big and
> > > complex like a scaler (sws, zscale) which should not live within
> > > libavfilter.
> > 
> > > Any change can be contributed back to libquirc
> > 
> > This is not realistic, given that a reimplementation would be possibly
> > completely refactored to fit into FFmpeg.
> > 
> > > (A library
> > > that's not going to be abandoned like it happened with libdcadec after it
> > > was merged into lavc,
> > 
> > OTOH, this library is quite outside the scope of the FFmpeg, so it
> > makes sense to keep it as external dependency. This is a quite
> > different use case than a decoder, a QR-decoder library can make sense
> > outside of a multimedia library, for a decoder you would need a
> > complete multimedia library anyway.
> > 
> > I was checking the code, and porting would be a serious effort and
> > comprise several thousands lines of code (against the moderate effort
> > of wrapping it - which is already done), also some of the logic would
> > not really fit into FFmpeg because it is quite specific to this
> > application domain (QR code decoding), so it makes sense for it to
> > live within an external library. Not to mention that this would be
> > a duplication of effort.
> 
> Image analysis is within FFmpeg's scope, which QR code identification and
> decoding would be about.
> 
> > 
> > *Unless* someone is willing to port/reimplement the code, but this
> > should not be a blocker for the wrapper and can be done as a separate
> > step.
> 
> No, i'm not blocking anything. Just stating that ideally this would be a
> native module.

I'm not against this of course, but as I already stated this would
require more effort. It is probably worth it (polynomials and Galois
fields based error correction) as they would be probably reused in
other parts of the code. Ditto for the QR encoder.

But I plan to have this functionality in with the wrappers - this
should also help with an eventual native port of the features.

I plan to push this patch in a few days, unless I see comments.

Thanks for the feedback.