Hi Monica,
I tested your SMIL file as follows:
- Before changing the audio language:
#EXTM3U
#EXT-X-VERSION:3
#EXT-X-MEDIA:TYPE=SUBTITLES,GROUP-ID="subs",NAME="Chinese",FORCED=NO,AUTOSELECT=YES,URI="subtitlelist_lzho_b48000_slCantonese_t64Q2FudG9uZXNl_cfNjk0NjU3LzI0MTEzNi50dG1s.m3u8",LANGUAGE="zho"
#EXT-X-MEDIA:TYPE=AUDIO,GROUP-ID="aac",LANGUAGE="Cantonese",NAME="Cantonese",DEFAULT=YES,URI="chunklist_b48000_ao_slCantonese_t64Q2FudG9uZXNl_cfNjk0NjU3LzI0MTEzNi50dG1s.m3u8"
#EXT-X-STREAM-INF:BANDWIDTH=3872001,AUDIO="aac",SUBTITLES="subs"
chunklist_b3872001_vo_cfNjk0NjU3LzI0MTEzNi50dG1s.m3u8
* STATE: PERFORM => DONE handle 0x600057620; line 1645 (connection #0)
* Curl_done
* Connection #0 to host localhost left intact
- Edited the audio language to English in the SMIL file as follows:
<?xml version="1.0"?>
<smil>
<head/>
<body>
<switch>
<video src="mp4:sample.mp4?audioindex=0" system-language="English" title="English" audio-bitrate="48000">
<param name="audioOnly" value="TRUE" valuetype="data"/>
<param name="cupertinoTag" value="EXT-X-MEDIA" valuetype="data"/>
<param name="cupertinoTag.GROUP-ID" value="aac" valuetype="data"/>
<param name="cupertinoTag.DEFAULT" value="YES" valuetype="data"/>
</video>
<video src="sample.mp4" system-bitrate="3872001">
<param name="videoOnly" value="TRUE" valuetype="data"/>
<param name="cupertinoTag.AUDIO" value="aac" valuetype="data"/>
</video>
<textstream src="241136.ttml" system-language="zho">
<param name="isWowzaCaptionStream" value="true"/>
</textstream>
</switch>
</body>
</smil>
- Generated playlist after the SMIL file edit:
#EXTM3U
#EXT-X-VERSION:3
#EXT-X-MEDIA:TYPE=SUBTITLES,GROUP-ID="subs",NAME="Chinese",FORCED=NO,AUTOSELECT=YES,URI="subtitlelist_lzho_b48000_slEnglish_t64RW5nbGlzaA==_cfNjk0NjU3LzI0MTEzNi50dG1s.m3u8",LANGUAGE="zho"
#EXT-X-MEDIA:TYPE=AUDIO,GROUP-ID="aac",LANGUAGE="English",NAME="English",DEFAULT=YES,URI="chunklist_b48000_ao_slEnglish_t64RW5nbGlzaA==_cfNjk0NjU3LzI0MTEzNi50dG1s.m3u8"
#EXT-X-STREAM-INF:BANDWIDTH=3872001,AUDIO="aac",SUBTITLES="subs"
chunklist_b3872001_vo_cfNjk0NjU3LzI0MTEzNi50dG1s.m3u8
* STATE: PERFORM => DONE handle 0x600057620; line 1645 (connection #0)
* Curl_done
* Connection #0 to host localhost left intact
Do make sure that you are saving the correct SMIL file, and that you are changing the values for both the system-language and the title parameters. In the example you copied above, it looks like your title was still set to Cantonese.
Hope this helps.
Michelle