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Subtitles M3u8 playlist not generated for WebVtt file

Open pscplayco opened this issue 7 years ago • 6 comments

When trying to package subtitles from a WebVTT file, using mp4dash tool, and in order to get an HLS stream, I'm getting a master playlist which is just pointing to a WebVTT file instead of an m3u8 subtitltes playlist. Therefore, the iOS native player and other HLS test players I've tried are not able to read and show subtitles.

This is the command I'm using: mp4dash --hls --subtitles [+format=webvtt,+language=ar]testfile.vtt *.mp4

And this is what I get into my master m3u8 playlist:

Subtitles

#EXT-X-MEDIA:TYPE=SUBTITLES,GROUP-ID="subs",NAME="ar",DEFAULT=NO,AUTOSELECT=YES,FORCED=YES,LANGUAGE="ar",URI="subtitles/ar/testfile.vtt"

The only way I've got it to work is:

  • creating an m3u8 subtitles playlist, pointing to the webvtt generated file
  • modifying the master playlist #EXT-X-MEDIA:TYPE=SUBTITLES tag, to point to the subtitles playlist instead of the webvtt file
  • adding the subtitles group to each of the #EXT-X-STREAM-INF

Do you think this is something that can be added to the code? Otherwise, if I were wrong, how can subtitles be added to the HLS stream, so that the native iOS player is able to fetch them correctly?

Thank you in advance

pscplayco avatar Aug 20 '18 14:08 pscplayco

I'm pretty sure this worked some time ago, maybe with older version of iOS or macOS. But it doesn't seem to match what in the most recent RFC, so I think WebVTT files should be referenced by a paylist rather than directly. I'll double check and make the fix if that's the case.

barbibulle avatar Aug 30 '18 19:08 barbibulle

  • creating an m3u8 subtitles playlist, pointing to the webvtt generated file

@pscplayco How do you create the m3u8 subtitle playlist?

ghost avatar Sep 23 '19 10:09 ghost

that was very long ago....but I think it was just manually generating it

pscplayco avatar Sep 23 '19 11:09 pscplayco

@pscplayco I want to add a url for a single vtt file into the master m3u8 and I can't find a proper way. I'm looking for a manual way as well.

ghost avatar Sep 23 '19 11:09 ghost

We still having this issue.

night91 avatar Mar 03 '20 17:03 night91

Yep

DrJapan avatar Feb 11 '22 03:02 DrJapan