mplayer: add page (#6874)

pages/common/mplayer.md

@@ -0,0 +1,28 @@
+# mplayer
+
+> Cross-platform multimedia player.
+> More information: <https://mplayerhq.hu/DOCS/HTML/en/commandline.html>.
+
+- Play the specified file or URL:
+
+`mplayer {{path/to/file|url}}`
+
+- Play multiple files:
+
+`mplayer {{path/to/file1 path/to/file2 ...}}`
+
+- Play a specific file repeatedly:
+
+`mplayer -loop {{0}} {{path/to/file}}`
+
+- Pause playback:
+
+`<Space>`
+
+- Quit mplayer:
+
+`<Escape>`
+
+- Seek backward or forward 10 seconds:
+
+`<Left> or <Right>`