add ffmpeg pixeldensity feature for retina displays

[i3roly]

sorry for the additional pull request, but i had to cleave out the nodejs patches and things were messy.

the comments to the patch files have been added.

the change does not affect people who do not have retina displays. you must invoke -movflags write_pixeldensity for the feature to have any effect.

as shown in the portfile comments, daniel kaiser has done all of the legwork but the ffmpeg team does not seem interested in adding the functionality. i did make a properly-formatted git patch for them and they seemed to not care.

Type(s)

• bugfix
• enhancement
• security fix

Tested on

macOS 10.14.6 18G9323 x86_64
Xcode 11.3.1 11C505

Verification

Have you

• followed our Commit Message Guidelines?
• squashed and minimized your commits?
• checked that there aren't other open pull requests for the same change?
• referenced existing tickets on Trac with full URL in commit message?
• checked your Portfile with port lint --nitpick?
• tried existing tests with sudo port test?
• tried a full install with sudo port -vst install?
• tested basic functionality of all binary files?
• checked that the Portfile's most important variants haven't been broken?

[macportsbot]

Notifying maintainers:
@dbevans for port ffmpeg.
@jeremyhu for port ffmpeg.
@mascguy for port ffmpeg-devel, ffmpeg.

[i3roly]

i have updated the patches. i didn't realise that the "a/" and "b/" suffixes would cause problems.

[barracuda156]

@i3roly Would you mind adding an unrelated fix here to avoid another revbump of all ffmpeg ports?
We need to add a dependency on xorg-libXv info x11 variant. See: https://trac.macports.org/ticket/71280

[i3roly]

what exactly should i do here? it seems that it is trying to link some libraries that don’t exist for or something? some more directions would be helpful. if i can, i will.

…

On Nov 11, 2024, at 7:10 PM, Sergey Fedorov ***@***.***> wrote: @i3roly Would you mind adding an unrelated fix here to avoid another revbump of all ffmpeg ports? We need to add a dependency on xorg-libXv info x11 variant. See: https://trac.macports.org/ticket/71280 — Reply to this email directly, view it on GitHub, or unsubscribe. You are receiving this because you were mentioned.

[barracuda156]

what exactly should i do here? it seems that it is trying to link some libraries that don’t exist for or something? some more directions would be helpful. if i can, i will.
…
On Nov 11, 2024, at 7:10 PM, Sergey Fedorov @.***> wrote: @i3roly Would you mind adding an unrelated fix here to avoid another revbump of all ffmpeg ports? We need to add a dependency on xorg-libXv info x11 variant. See: https://trac.macports.org/ticket/71280 — Reply to this email directly, view it on GitHub, or unsubscribe. You are receiving this because you were mentioned.

Ah, wait, it is a bit more tricky. Originally this error was found with x11 variant and fixed: https://trac.macports.org/ticket/58617
Apparently, however, ffmpeg links to some x11 libs even without +x11 variant, which is wrong.

I will look into why that happens.

[i3roly]

can we merge what we have now please? i don't want to keep applying the patch every time there's an ffmpeg update

[barracuda156]

@i3roly Yeah, no need to wait for x11 issue to be sorted out, it may take a bit of time. There is a ticket for it: https://trac.macports.org/ticket/71353
Rather revbump all ffmpegs whenever that gets fixed.

[mascguy]

LGTM, thank you so much for your contribution!

[mohd-akram]

Something wrong with this patch? Why is this mentioned twice? Same for the ffmpeg7 port in #27440.