ffmpeg: 4.3.2 -> 4.4

[TredwellGit]

Motivation for this change

https://github.com/FFmpeg/FFmpeg/blob/n4.4/Changelog

Things done

• Tested using sandboxing (nix.useSandbox on NixOS, or option sandbox in nix.conf on non-NixOS linux)
• Built on platform(s)
  • NixOS
• Tested execution of all binary files (usually in ./result/bin/)
• Fits CONTRIBUTING.md.

[vcunat]

It won't build on x86_64-darwin

libavcodec/videotoolboxenc.c:1036:29: error: use of undeclared identifier 'TARGET_CPU_ARM64'
    return TARGET_OS_OSX && TARGET_CPU_ARM64;

As a fallback, we might e.g. get 4.3 back just for darwin, even though it's not ideal.

[vs49688]

@vcunat I'm working with upstream on this, what SDK version are we building with?

[vcunat]

@vs49688: 10.12, I think. I'm not involved but it seems clear from pkgs/os-specific/darwin/apple-sdk/default.nix

[vcunat]

Overall, perhaps it would be better to keep NixOS 21.05 default on ffmpeg 4.3.x? I see also mplayer regressing: https://hydra.nixos.org/build/142702864

/cc @NixOS/nixos-release-managers #122068 (ffmpeg doesn't cause that huge rebuild)

[vs49688]

That's been fixed in a newer revision of mplayer. I'm backporting it now.

[jonringer]

21.05 doesn't need a backport yet. There hasn't been a branchoff yet

[vs49688]

I meant backporting the mplayer fix. Here 'tis: #123068

[vcunat]

I'm working with upstream on this, what SDK version are we building with?

@vs49688: any outlooks for that? (the darwin build)

[vs49688]

@vcunat Submitted draft PR, waiting for ofborg to build it as I don't have any OSX machines. #123169
Patch (v2): https://ffmpeg.org/pipermail/ffmpeg-devel/2021-May/280337.html
Bug: https://trac.ffmpeg.org/ticket/9242

EDIT: Could someone request a darwin build from ofborg on the above pr? I don't have permissions.