l mpv: add autosub script

lass/2configs/mpv.nix

@@ -2,11 +2,84 @@
 
 let
 
+  download_subs = pkgs.writers.writePython3 "download_sub" {
+    libraries = [ pkgs.python3Packages.subliminal ];
+  } ''
+    from subliminal import download_best_subtitles, scan_video
+    from babelfish import Language
+    import sys
+
+    video_filename = sys.argv[1]
+
+    vid = scan_video(video_filename)
+    sub = download_best_subtitles([vid], {Language('eng')})[vid][0]
+
+    filename = '/tmp/' + vid.title + '.srt'
+
+    with open(filename, 'wb+') as file:
+        file.write(sub.content)
+
+    print(filename)
+  '';
+
+  autosub = pkgs.writeText "autosub.lua" ''
+    -- Requires Subliminal version 1.0 or newer
+    -- Make sure to specify your system's Subliminal location below:
+    local utils = require 'mp.utils'
+
+    -- Log function: log to both terminal and mpv OSD (On-Screen Display)
+    function log(string, secs)
+        secs = secs or 2     -- secs defaults to 2 when the secs parameter is absent
+        mp.msg.warn(string)          -- This logs to the terminal
+        mp.osd_message(string, secs) -- This logs to mpv screen
+    end
+
+    function download()
+        log('Searching subtitles ...', 10)
+        table = { args = {"${download_subs}", mp.get_property('path')} }
+        result = utils.subprocess(table)
+        if result.error == nil then
+            -- remove trailing newline from subtitle filename
+            filename = string.gsub(result.stdout, "\n", "")
+            log(filename)
+            mp.commandv('sub_add', filename)
+            log('Subtitles ready!')
+        else
+            log('Subtitles failed downloading')
+        end
+    end
+
+    -- Control function: only download if necessary
+    function control_download()
+        duration = tonumber(mp.get_property('duration'))
+        if duration < 900 then
+            mp.msg.warn('Video is less than 15 minutes\n', '=> NOT downloading any subtitles')
+            return
+        end
+        -- There does not seem to be any documentation for the 'sub' property,
+        -- but it works on both internally encoded as well as external subtitle files!
+        -- -> sub = '1' when subtitles are present
+        -- -> sub = 'no' when subtitles are not present
+        -- -> sub = 'auto' when called before the 'file-loaded' event is triggered
+        sub = mp.get_property('sub')
+        if sub == '1' then
+            mp.msg.warn('Sub track is already present\n', '=> NOT downloading other subtitles')
+            return
+        end
+        mp.msg.warn('No sub track was detected\n', '=> Proceeding to download subtitles:')
+        download()
+    end
+
+    mp.register_event('file-loaded', control_download)
+    mp.add_key_binding('S', "download_subs", download)
+  '';
+
   mpv = pkgs.symlinkJoin {
     name = "mpv";
     paths = [
       (pkgs.writeDashBin "mpv" ''
-        exec ${pkgs.mpv}/bin/mpv --no-config "$@"
+        exec ${pkgs.mpv}/bin/mpv --no-config --script=${autosub} "$@"
+        # exec ${pkgs.mpv}/bin/mpv --no-config "$@"
       '')
       pkgs.mpv
     ];