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

[James Almer]

On 12/27/2023 8:37 AM, Stefano Sabatini wrote:
> On date Tuesday 2023-12-26 22:33:36 -0300, James Almer wrote:
>> On 12/26/2023 10:25 PM, Stefano Sabatini wrote:
>>> On date Tuesday 2023-12-26 17:20:33 +0100, Stefano Sabatini wrote:
>>>> ---
>>>>    Changelog                |   1 +
>>>>    configure                |   4 +
>>>>    doc/filters.texi         |  35 ++++++++
>>>>    libavfilter/Makefile     |   1 +
>>>>    libavfilter/allfilters.c |   1 +
>>>>    libavfilter/vf_quirc.c   | 183 +++++++++++++++++++++++++++++++++++++++
>>>>    6 files changed, 225 insertions(+)
>>>>    create mode 100644 libavfilter/vf_quirc.c
>>>
>>> V2 with a few fixes and all corners put in the metadata (e.g. in case
>>> the QR code is rotated).
>>
> 
>> Looking at the library, the license is very permissive and the code hasn't
>> been touched in many years. It is also pretty small, so why not just add it
>> as a native filter instead of requiring an external dependency for what
>> seems to be a relatively simple process?
> 
> I see pros and cons, in total that would be about 3K lines of pretty
> clean code and data, and this would simplify integration for end-users
> (since they would not need to build the library, which seems not
> packaged by many distributions), and having the code would help to
> solve similar problems and probably could be generalized and optimized
> (e.g. to support other pixel formats).
> 
> OTOH it would add to the maintenance burden since we would be owners
> of the code, which also means we would not benefit from fixes to the
> upstream project, in case they happen (last commit is from March
> 2023, so not very old):
> https://github.com/dlbeer/quirc/commit/542848dd6b9b0eaa9587bbf25b9bc67bd8a71fca

That's a build system change, so not really relevant. Last real change 
was 
https://github.com/dlbeer/quirc/commit/cc673124335785d220dbb9057b21c51e4a87e0b2, 
also from March 2023, but the one before it is from August 2021.

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 (A library 
that's not going to be abandoned like it happened with libdcadec after 
it was merged into lavc, because its license is more permissive than our 
LGPL, which has its merits).

Lets try to keep external dependencies as limited as possible.