TOOLS/autocrop.lua: update comment

TOOLS/lua/autocrop.lua

@@ -1,79 +1,59 @@
 --[[
-This script uses the lavfi cropdetect filter to automatically
-insert a crop filter with appropriate parameters for the
-currently playing video.
+This script uses the lavfi cropdetect filter and the video-crop property to
+automatically crop the currently playing video with appropriate parameters.
 
-It will automatically crop the video, when playback starts.
+It automatically crops the video when playback starts.
 
-Also It registers the key-binding "C" (shift+c). You can manually
-crop the video by pressing the "C" (shift+c) key.
+You can also manually crop the video by pressing the "C" (shift+c) key.
+Pressing it again undoes the crop.
 
-If the "C" key is pressed again, the crop filter is removed
-restoring playback to its original state.
+The workflow is as follows: First, it inserts the cropdetect filter. After
+<detect_seconds> (default is 1) seconds, it then sets video-crop based on the
+vf-metadata values gathered by cropdetect. The cropdetect filter is removed
+after video-crop is set as it is no longer needed.
 
-The workflow is as follows: First, it inserts the filter
-vf=lavfi=cropdetect. After <detect_seconds> (default is 1)
-seconds, 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.
+Since the crop parameters are determined from the 1 second of video between
+inserting the cropdetect filter and setting video-crop, 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).
 
-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).
+If non-copy-back hardware decoding is in use, hwdec is temporarily set to
+auto-copy-safe for the duration of cropdetect as the filter would fail
+otherwise.
 
-The default options can be overridden by adding
-script-opts-append=autocrop-<parameter>=<value> into mpv.conf
-
-List of available parameters (For default values, see <options>)：
-
-auto: bool - Whether to automatically apply crop at the start of
-    playback. If you don't want to crop automatically, set it to
-    false or add "script-opts-append=autocrop-auto=no" into
-    mpv.conf.
-
-auto_delay: seconds - Delay before starting crop in auto mode.
-    You can try to increase this value to avoid dark scene or
-    fade in at beginning. Automatic cropping will not occur if
-    the value is larger than the remaining playback time.
-
-detect_limit: number[0-255] - Black threshold for cropdetect.
-    Smaller values will generally result in less cropping.
-    See limit of https://ffmpeg.org/ffmpeg-filters.html#cropdetect
-
-detect_round: number[2^n] -  The value which the width/height
-    should be divisible by. Smaller values ​​have better detection
-    accuracy. If you have problems with other filters,
-    you can try to set it to 4 or 16.
-    See round of https://ffmpeg.org/ffmpeg-filters.html#cropdetect
-
-detect_min_ratio: number[0.0-1.0] - The ratio of the minimum clip
-    size to the original. If the picture is over cropped or under
-    cropped, try adjusting this value.
-
-detect_seconds: seconds - How long to gather cropdetect data.
-    Increasing this may be desirable to allow cropdetect more
-    time to collect data.
-
-suppress_osd: bool - Whether the OSD shouldn't be used when filters
-    are applied and removed.
+These are the default options. They can be overridden by adding
+script-opts-append=autocrop-<parameter>=<value> to mpv.conf.
 --]]
-
-require "mp.msg"
-require 'mp.options'
-
 local options = {
+    -- Whether to automatically apply crop at the start of playback. If you
+    -- don't want to crop automatically, add
+    -- script-opts-append=autocrop-auto=no to mpv.conf.
     auto = true,
+    -- Delay before starting crop in auto mode. You can try to increase this
+    -- value to avoid dark scenes or fade ins at beginning. Automatic cropping
+    -- will not occur if the value is larger than the remaining playback time.
     auto_delay = 4,
+    -- Black threshold for cropdetect. Smaller values will generally result in
+    -- less cropping. See limit of
+    -- https://ffmpeg.org/ffmpeg-filters.html#cropdetect
     detect_limit = "24/255",
+    -- The value which the width/height should be divisible by. Smaller
+    -- values have better detection accuracy. If you have problems with
+    -- other filters, you can try to set it to 4 or 16. See round of
+    -- https://ffmpeg.org/ffmpeg-filters.html#cropdetect
     detect_round = 2,
+    -- The ratio of the minimum clip size to the original. A number from 0 to
+    -- 1. If the picture is over cropped, try adjusting this value.
     detect_min_ratio = 0.5,
+    -- How long to gather cropdetect data. Increasing this may be desirable to
+    -- allow cropdetect more time to collect data.
     detect_seconds = 1,
+    -- Whether the OSD shouldn't be used when cropdetect and video-crop are
+    -- applied and removed.
     suppress_osd = false,
 }
-read_options(options)
+
+require "mp.options".read_options(options)
 
 local label_prefix = mp.get_script_name()
 local labels = {