On Sat, 21 Mar 2026, 15:52 Michael Niedermayer via ffmpeg-devel, <
[email protected]> wrote:

> Hi everyone
>
> 2 days ago "tests/checkasm: switch to shared libcheckasm implementation
> #22546"
> was opened
>
> This is not a small refactor. It adds 651 commits, touches 117 files, and
> adds 19405 lines and removes 1940.
> That scope merits broader review and discussion before any merge decision.
>
> I have several concerns.
>
> First, a dependancy on external infrastructure is unnecceasry
>
> Second, a dependancy on gitlab-CI is not acceptable
> We need to be able to run the full relevant test coverage ourselves, under
> FFmpeg-controlled infrastructure
>
> Third, the copyright and authorship situation needs clarification.
>     The copyrights after the PR
>     git grep Copyright  tests/checkasm/ | sed 's/.*:[ *;#]*//' | sed
> 's/([cC])/©/' | sed 's/,//' | sort | uniq -c | sort -n  | tail -10
>         3 Copyright © 2024 Marvin Scholz
>         4 Copyright © 2015 James Almer
>         4 Copyright © 2015 Janne Grunau
>         4 Copyright © 2023 Institute of Software Chinese Academy of
> Sciences (ISCAS).
>         5 Copyright © 2025 Martin Storsjo
>         6 Copyright © 2016 Alexandra Hájková
>         8 Copyright © 2015 Henrik Gramner
>         37 Copyright © 2018 Two Orioles, LLC
>         45 Copyright © 2018 VideoLAN and dav1d authors
>         45 Copyright © 2025 Niklas Haas
>
>     But the actual authorship in tests/checkasm/ is dominated by FFmpeg
> contributors, for example:
>     git shortlog -s -n tests/checkasm/ | head -10
>        120      Andreas Rheinhardt
>         87      James Almer
>         80      Martin Storsjö
>         44      Rémi Denis-Courmont
>         29      Henrik Gramner
>         28      Michael Niedermayer
>         27      Niklas Haas
>         23      Clément Bœsch
>         18      Hendrik Leppkes
>         18      Martin Vignali
>
>     the authorship in the added commits is likewise specific and
> attributable:
>     git shortlog -s -n origin..
>           450  Niklas Haas
>           128  Martin Storsjö
>            25  Rémi Denis-Courmont
>            22  Cameron Cawley
>            11  Marvin Scholz
>             6  Nathan E. Egge
>             3  KO Myung-Hun
>             2  J. Dekker
>             1  Brad Smith
>             1  Felix Paul Kühne
>             1  Henrik Gramner
>             1  Konstantin Pavlov
>
>     So at least from a first look, this appears to remove or dilute FFmpeg
> attribution
>     while adding blanket notices such as “VideoLAN and dav1d authors” to
> many files,
>     even though that is not a literal commit author. That needs a proper
> explanation before anything proceeds.
>
> Forth,
>     "Some changes have been ported over from FFmpeg's copy of checkasm,
> with permission to relicense."
>
>     My permission for relicensing was conditional on the resulting project
> being hosted on code.ffmpeg.org.
>     That condition was never fulfilled. So unless I am missing something,
> that statement is at best
>     incomplete and may be misleading.
>
> Fifth,
>     the libcheckasm work was done by FFlabs people and discussed in FFlabs
> meetings.
>     So unless I misunderstand the situation, we seem to have funded work
> that now removes FFmpeg attribution or identity,
>     adds a dependency on external infrastructure, and moves testing in a
> direction tied to systems FFmpeg does not control and previously did not
> choose.
>
> Please correct me if I am wrong, but from where I stand this proposal
> raises significant technical,
> governance, infrastructure, and attribution concerns, and I do not think
> it should be merged in its current form.
>

Checkasm came from x264 originally, a VideoLAN project.

It is the right decision to not have various forks of checkasm (you would
agree, no?). Many companies, mine included, also maintain forks and would
like a standalone checkasm.

You also seem to misunderstand concepts around collective work in copyright.

You are effectively demanding an FFmpeg takeover of Checkasm. This is not
acceptable.

Kieran

>
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