python3Packages.av: fix build

[emilazy]

Description of changes

Many of the tests depend on sample files fetched over HTTP and they keep adding more. Since they support a caching mechanism, use it to pre‐fetch all the used samples instead.

It might be nice to have a package for the full FATE suite, but it’s over 1 GiB in size so I just did this for now.

Fixes: ca258d2

Going to run a full nixpkgs-review on a master‐based version of this, but it’s probably fine to merge optimistically.

Things done

• Built on platform(s)
  • x86_64-linux
  • aarch64-linux
  • x86_64-darwin
  • aarch64-darwin
• For non-Linux: Is sandboxing enabled in nix.conf? (See Nix manual)
  • sandbox = relaxed
  • sandbox = true
• Tested, as applicable:
  • NixOS test(s) (look inside nixos/tests)
  • and/or package tests
  • or, for functions and "core" functionality, tests in lib/tests or pkgs/test
  • made sure NixOS tests are linked to the relevant packages
• Tested compilation of all packages that depend on this change using nix-shell -p nixpkgs-review --run "nixpkgs-review rev HEAD". Note: all changes have to be committed, also see nixpkgs-review usage
• Tested basic functionality of all binary files (usually in ./result/bin/)
• 24.11 Release Notes (or backporting 23.11 and 24.05 Release notes)
  • (Package updates) Added a release notes entry if the change is major or breaking
  • (Module updates) Added a release notes entry if the change is significant
  • (Module addition) Added a release notes entry if adding a new NixOS module
• Fits CONTRIBUTING.md.

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[Atemu]

We might want to reconsider running these tests at all if they require such maintenance overhead or imply huge build time closures.

[emilazy]

In this current PR it’s like 16 MiB of samples and one bash script to keep them updated in case they add more; I think it’s fine. The overhead was manually disabling every test that wants a sample file, which should no longer be necessary. There’s upstream issues at PyAV-Org/PyAV#623 and PyAV-Org/PyAV#955 (hi @mweinelt).

At some point it might be nice to run the full FATE test suite against our FFmpeg builds, really, at which point we’d have to start thinking about size.

[emilazy]

This breaks Home Assistant’s weird PyAV fork thing… I’ll look into it tomorrow.

[Atemu]

cc @mweinelt

[drupol]

nice!

[emilazy]

I just talked with @mweinelt on Matrix and we’re going to try replacing Home Assistant’s outdated PyAV fork with the real thing. Will report back on the nixpkgs-review results when I have them.

[emilazy]

Alright, this has no regressions vs. Hydra on master (except whisper-ctranslate2 which doesn’t look related so it’s probably an issue with my regression testing methodology?). Should be good to merge.