Extract 9:16 thumbs from video & using VTT seems to lose the resize about imgproxy HOT 12 OPEN

Hey @routehero!

vtt always does "resize--to-fit" scaling. Currently, the only way to get tiles of the exact size provided is using the extend_tile argument of vtt: vtt:1:5:5:120:160:1. Though I guess this is not what you want.

from imgproxy.

extend is cool, but first I'd like to ensure that every thumbnail in the tile is cropped/scaled.

Goal is to get 9:16 thumbs in the tile.

from imgproxy.

I can add an argument that would enable "resize-to-fill" scaling of the tiles, but it will always use the center of a frame (as with ce gravity). Would it work for you?

from imgproxy.

On our site, we plan to have a feature where the user can select a 9:16 portion of a 16:9 video.

Using ffmpeg, I would do something like:

only iframes:
ffmpeg -y -skip_frame nokey -i ../bbb_sunflower_1080p_30fps_normal.mp4 -vf "fps=1/5,crop=x=0:y=0:w=ih*9/16,scale=480:640,tile=5x5" test%05d.jpg

all frames:
ffmpeg -y -i ../bbb_sunflower_1080p_30fps_normal.mp4 -vf "fps=1/5,crop=x=0:y=0:w=ih*9/16,scale=480:640,tile=5x5" test2%05d.jpg

Being able to specify the x= parameter in this case is key to the feature, so center-based gravity would not be appropriate.

from imgproxy.

Well, it's possible. But I'd rather allow specifying a focus point (like in the fp gravity) instead of offsets. The focus point is generally easier to use and it can have proper defaults (0.5x0.5 for center). From the frontend's point of view, it's a little bit more complex but not rocket science. Basically, it can be calculated as (x_offset + selected_area_width/2) / video_width. What do you think about this?

from imgproxy.

Sounds good to me.

from imgproxy.

I made a test build test-vtk-fill that adds 3 additional arguments to vtt. Now its arguments look like this:

vtt:%step:%columns:%rows:%tile_width:%tile_height:%extend_tile:%trim:%fill:%focus_x:%focus_y

fill: when set to 1, t or true, imgproxy will resize frames to fill a tile and will crop projecting parts (as with resizing_type:fill).
focus_x and focus_y: floating point numbers between 0 and 1 that define the coordinates of the center of the tile. Treat 0 and 1 as right/left for focus_x and top/bottom for focus_y. Applicable only when fill is used.

Please check if this does the job for you.

from imgproxy.

Initial testing looks good to me!

from imgproxy.

Nice! Please drop a line here when you make sure it works for you so I can merge this to the upstream.

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