vout: add Fill display fit mode

On Android there's a fit mode where the whole video area is filled with the video, stretching if necessary.

changed milestone to %4.0

added Component::Core: Video output label

mentioned in merge request libvlcjni!100

added MRStatus::Reviewable label

added 2 commits

• f2f27b21 - display: only compute the scaled dimensions when we use them
• 16ede660 - display: reduce line length and reorder variables

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added MRStatus::NotCompliant label and removed MRStatus::Reviewable label

added MRStatus::Reviewable label and removed MRStatus::NotCompliant label

added 3 commits

• 578351c1 - display: force VLC_VIDEO_FIT_FILL for non rectangulat (360) videos
• 34c8fbf0 - display: always use 0,0 video placetment in VLC_VIDEO_FIT_FILL mode
• 82336398 - display: return early for VLC_VIDEO_FIT_FILL

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I disagree. This is redundant with fitting to the largest dimension, and changing the aspect ratio, both of which we already have.

Perhaps there should be a magic aspect ratio value to match the window aspect ratio, but that's a different thing then.

The way it's done in Android does allow to tweak the aspect ratio: libvlcjni!100 (ed69d76a)

I can give this a try but that seems hackish compared to a "fitting" mode which in this case really means the video placement should be have no offset and use the whole display width/height. Hijacking a special aspect ratio in the source format so it's placed that way seems odd. This will get even worse when the source video has cropping inside its original format.

It could also be an aspect ratio we change every time the window dimension changes. But that means micro-managing the aspect ratio, setting the value every time a pixel is added/removed and it may not be handled right away since they are handled in different threads.

However it's true that the fitting and aspect-ratio are in contradiction in this case. If a user wants a video to be considered as 16:9 and yet wants to fit it the whole display area, the 16:9 won't be respected (when the display area is not 16:9).

Not sure what a special value could be. For now the integer values are unsigned in the string. And 0:0 means the display aspect ratio is not forced.

As expected, it seems hackish. For this to work, that means all display modules must use vd->source to place the video inside the display area. That's where the final aspect ratio will be passed to the display module, which will compensate for the window size.

Looking at all the display modules, some don't call vout_display_PlacePicture() with vd->source but with a custom format. d3d11 in particular only uses it on startup but not later. I should fix that. But that means we need a pass on vout_display_PlacePicture() to make sure they all handle aspect ratio changes in the source properly.

This is also a problem when the filling mode is set in the vout_display_placement because some modules like MMAL force the fitting mode (probably wrong).

(another good reason the video placement shouldn't be left to each display module, especially since the core already has its own to place subpictures)

added MRStatus::InReview label and removed MRStatus::Reviewable label

mentioned in merge request !6042

Closing in favor of !6042

closed