support for YouTube app HLS video language choice. also fix #452

README.md

@@ -2,6 +2,10 @@
 
 ### **Now developed at the GitHub site <https://github.com/FDH2/UxPlay> (where ALL user issues should be posted, and latest versions can be found).**
 
+--  **NEW on github**: some YouTube app HLS videos now offer alternative language tracks (generated by AI dubbing).  Language choices will be made in order of
+     preferences set with option -lang (or by environment variable $LANGUAGE, which it overrides). Format is `-lang fr:es:en`, where French ("fr") is
+     the first choice, if available, then Spanish ("es"), etc.   $LANGUAGE has the same format. `-lang` by itself suppresses playing of dubbed audio.
+
 -   **NEW on github**: Support for **service discovery using a Bluetooth LE "beacon"** for both Linux/\*BSD and Windows (as an alternative to Bonjour/Rendezvous DNS-SD
     service discovery).    The user must set up a Bluetooth LE "beacon", (a USB 4.0 or later "dongle" can be used). See instructions
     below.   The beacon runs independently of UxPlay and regularly broadcasts a Bluetooth LE ("Low Energy") 46 byte packet informing nearby iOS/macOS devices of
@@ -1103,6 +1107,14 @@ allows selection of the version of GStreamer's
 is the recommended player, but if some videos fail to play, you can try
 with version 2.)_
 
+**-lang \[list\]**  Specify language preferences for YouTube app HLS videos,
+which may offer a choice of language (based on AI dubbing). If this option is not 
+used, preferences will be taken from environment variable $LANGUAGE, if set.    Both 
+methods specify the preference order as e.g. list =  `fr:es:en`, fot French (first 
+choice), Spanish (second choice), and  English (third choice).   
+If "list" is not given (or list = 0), $LANGUAGE is ignored and undubbed audio is played.
+
+
 **-scrsv n**. (since 1.73) (So far, only implemented
 on Linux/*BSD systems using D-Bus). Inhibit the screensaver in the
 absence of keyboard input (e.g., while watching video), using the
@@ -1927,7 +1939,8 @@ specified). (D-Bus based) option -scrsv <n> to inhibit screensaver while UxPlay
 is running (Linux/*BSD only).   Add support for Service  Discovery using a
 Bluetooth LE beacon.   Add -vrtp option for forwarding decrypted h264/5 video
 to an external renderer (e.g., OBS Studio).  Check that option input strings
-have valid UTF-8 encoding.
+have valid UTF-8 encoding.   New option `-lang fr:es:en` to specify language
+preferences for YouTube  HLS videos when they offer a choice. 
 
 1.72.2 2025-07-07  Fix bug (typo) in DNS_SD advertisement introduced with -pw
 option.  Update llhttp to v 9.3.0