Grosse maj

Scripts/autocrop.lua

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+-- This script uses the lavfi cropdetect filter to automatically
+-- insert a crop filter with appropriate parameters for the currently
+-- playing video.
+--
+-- It registers the key-binding "C" (shift+c), which when pressed,
+-- inserts the filter vf=lavfi=cropdetect. After 1 second, it then
+-- inserts the filter vf=crop=w:h:x:y, where w,h,x,y are determined
+-- from the vf-metadata gathered by cropdetect. The cropdetect filter
+-- is removed immediately after the crop filter is inserted as it is
+-- no longer needed.
+--
+-- If the "C" key is pressed again, the crop filter is removed
+-- restoring playback to its original state.
+--
+-- Since the crop parameters are determined from the 1 second of video
+-- between inserting the cropdetect and crop filters, the "C" key
+-- should be pressed at a position in the video where the crop region
+-- is unambiguous (i.e., not a black frame, black background title
+-- card, or dark scene).
+--
+-- The default delay between insertion of the cropdetect and
+-- crop filters may be overridden by adding
+--
+-- --script-opts=autocrop.detect_seconds=<number of seconds>
+--
+-- to mpv's arguments. This may be desirable to allow cropdetect more
+-- time to collect data.
+require "mp.msg"
+
+script_name = mp.get_script_name()
+cropdetect_label = string.format("%s-cropdetect", script_name)
+crop_label = string.format("%s-crop", script_name)
+
+-- number of seconds to gather cropdetect data
+detect_seconds = tonumber(mp.get_opt(string.format("%s.detect_seconds", script_name)))
+if not detect_seconds then
+    detect_seconds = 1
+end
+
+function del_filter_if_present(label)
+    -- necessary because mp.command('vf del @label:filter') raises an
+    -- error if the filter doesn't exist
+    local vfs = mp.get_property_native("vf")
+    for i,vf in pairs(vfs) do
+        if vf["label"] == label then
+            table.remove(vfs, i)
+            mp.set_property_native("vf", vfs)
+            return true
+        end
+    end
+    return false
+end
+
+function autocrop_start()
+    -- exit if cropdetection is already in progress
+    if timer then
+        mp.msg.warn("already cropdetecting!")
+        return
+    end
+
+    -- if there's a crop filter, remove it and exit
+    if del_filter_if_present(crop_label) then
+        return
+    end
+
+    -- insert the cropdetect filter
+    ret=mp.command(
+        string.format(
+            'vf add @%s:cropdetect=limit=%f:round=2:reset=0',
+            cropdetect_label, 24/255
+        )
+    )
+    -- wait to gather data
+    timer=mp.add_timeout(detect_seconds, do_crop)
+end
+
+function do_crop()
+    -- get the metadata
+    local cropdetect_metadata = mp.get_property_native(
+        string.format("vf-metadata/%s", cropdetect_label)
+    )
+
+    -- use it to crop if its valid
+    if cropdetect_metadata then
+        if cropdetect_metadata["lavfi.cropdetect.w"]
+            and cropdetect_metadata["lavfi.cropdetect.h"]
+            and cropdetect_metadata["lavfi.cropdetect.x"]
+            and cropdetect_metadata["lavfi.cropdetect.y"]
+        then
+            mp.command(string.format("vf add @%s:lavfi-crop=w=%s:h=%s:x=%s:y=%s",
+                                     crop_label,
+                                     cropdetect_metadata["lavfi.cropdetect.w"],
+                                     cropdetect_metadata["lavfi.cropdetect.h"],
+                                     cropdetect_metadata["lavfi.cropdetect.x"],
+                                     cropdetect_metadata["lavfi.cropdetect.y"]))
+        else
+            mp.msg.error(
+                "Got empty crop data. You might need to increase detect_seconds."
+            )
+        end
+    else
+        mp.msg.error(
+            "No crop data. Was the cropdetect filter successfully inserted?"
+        )
+        mp.msg.error(
+            "Does your version of ffmpeg/libav support AVFrame metadata?"
+        )
+    end
+    -- remove the cropdetect filter
+    del_filter_if_present(cropdetect_label)
+    timer=nil
+end
+
+mp.add_key_binding("C", "auto_crop", autocrop_start)