Hello,
I'm trying to create an HLS manifest for VOD that has four WebVTT subtitle tracks representing full subtitles and forced subtitles for both English and Spanish. This same manifest will of course also have no fewer than 6 audio tracks (2.0 AAC, 5.1 AC3 and 5.1 E-AC3 for both English and Spanish). The playback environment for testing is ***** Safari (just navigating directly to the manfiest URL). We'll add things like FairPlay later.
The desired behavior at a minimum is for all 4 subtitle tracks to be visible when loading the manifest in Safari. It would be ideal if forced subtitles show up when the subtitle selector is set to auto, and will switch from english to spanish if the user switches the audio track, and to have the full subtitle tracks available as options regardless of what audio language is streaming.
Here was my first attempt:
#EXT-X-MEDIA:TYPE=SUBTITLES,GROUP-ID="capt_1",LANGUAGE="en",NAME="English Forced Subtitles",DEFAULT=YES,AUTOSELECT=YES,URI="presentation_s1/prog_index.m3u8" #EXT-X-MEDIA:TYPE=SUBTITLES,GROUP-ID="capt_1",LANGUAGE="en",NAME="English Subtitles",AUTOSELECT=YES,URI="presentation_s2/prog_index.m3u8" #EXT-X-MEDIA:TYPE=SUBTITLES,GROUP-ID="capt_1",LANGUAGE="es",NAME="Spanish Forced Subtitles",AUTOSELECT=YES,URI="presentation_s3/prog_index.m3u8" #EXT-X-MEDIA:TYPE=SUBTITLES,GROUP-ID="capt_1",LANGUAGE="es",NAME="Spanish Subtitles",AUTOSELECT=YES,URI="presentation_s4/prog_index.m3u8"
This sort of worked. The forced subtitles did play, but the full subtitles were not selectable. I realized that I'd neglected to set the FORCED=TRUE flag on the two forced streams, so I tried again with that:
#EXT-X-MEDIA:TYPE=SUBTITLES,GROUP-ID="capt_1",LANGUAGE="en",NAME="English Forced Subtitles",DEFAULT=YES,AUTOSELECT=YES,FORCED=YES,URI="presentation_s1/prog_index.m3u8" #EXT-X-MEDIA:TYPE=SUBTITLES,GROUP-ID="capt_1",LANGUAGE="en",NAME="English Subtitles",AUTOSELECT=YES,URI="presentation_s2/prog_index.m3u8" #EXT-X-MEDIA:TYPE=SUBTITLES,GROUP-ID="capt_1",LANGUAGE="es",NAME="Spanish Forced Subtitles",AUTOSELECT=YES,FORCED=YES,URI="presentation_s3/prog_index.m3u8" #EXT-X-MEDIA:TYPE=SUBTITLES,GROUP-ID="capt_1",LANGUAGE="es",NAME="Spanish Subtitles",AUTOSELECT=YES,URI="presentation_s4/prog_index.m3u8"
This time I got full subtitles to show up, but I never see the forced subtitles, regardless of setting.
How should my subtitle tags look given my desired behavior? I'm using Unified Streaming Packager to create these packages, but can manually manipulate the manifests if necessary.
