HLS master playlist with redundant alternate audio tracks?

Question

Created Apr ’21

Replies 1

Boosts 0

Views 1.8k

Participants 2

For a Live stream (HLS LIVE), I need to enable redundancy of alternate audio tracks in the playlist definition.
Any idea how to enable such support in the playlist on EXT-X-MEDIA?

example: (XXXXXX and XXXXXX-b for the redundant url)

Code Block #EXTM3U
#EXT-X-VERSION:4
#EXT-X-INDEPENDENT-SEGMENTS
#EXT-X-MEDIA:TYPE=AUDIO,GROUP-ID="audio1",NAME="FRA",DEFAULT=YES,AUTOSELECT=YES,LANGUAGE="FRA",URI="https://hostname/hls/live/XXXXXX/streamname/stream05/streamPlaylist.m3u8"
#EXT-X-MEDIA:TYPE=SUBTITLES,GROUP-ID="subs",NAME="fra",DEFAULT=NO,AUTOSELECT=YES,LANGUAGE="fra",CHARACTERISTICS="public.accessibility.describes-music-and-sound",URI="https://hostname/hls/live/XXXXXX/streamname/stream108/streamPlaylist.m3u8"
#EXT-X-STREAM-INF:PROGRAM-ID=1,BANDWIDTH=1277113,RESOLUTION=640x360,FRAME-RATE=25.000,AUDIO="audio1",SUBTITLES="subs"
https://hostname/hls/live/XXXXXX/streamname/stream02/streamPlaylist.m3u8
#EXT-X-STREAM-INF:PROGRAM-ID=1,BANDWIDTH=1277113,RESOLUTION=640x360,FRAME-RATE=25.000,AUDIO="audio1",SUBTITLES="subs"
https://hostname/hls/live/XXXXXX-b/streamname/stream02/streamPlaylist.m3u8
#EXT-X-STREAM-INF:PROGRAM-ID=1,BANDWIDTH=658961,RESOLUTION=384x216,FRAME-RATE=25.000,AUDIO="audio1",SUBTITLES="subs"
https://hostname/hls/live/XXXXXX/streamname/stream01/streamPlaylist.m3u8
#EXT-X-STREAM-INF:PROGRAM-ID=1,BANDWIDTH=658961,RESOLUTION=384x216,FRAME-RATE=25.000,AUDIO="audio1",SUBTITLES="subs"
https://hostname/hls/live/XXXXXX-b/streamname/stream01/streamPlaylist.m3u8

Boost

Answer 1

Media Engineer OP

Apple

Jun ’21

The redundant variants should reference duplicate groups that are located under the alternate location.

#EXT-X-VERSION:4
#EXT-X-INDEPENDENT-SEGMENTS

#EXT-X-MEDIA:TYPE=AUDIO,GROUP-ID="audio1",NAME="FRA",DEFAULT=YES,AUTOSELECT=YES,LANGUAGE="FRA",URI="https://hostname/hls/live/XXXXXX/streamname/stream05/streamPlaylist.m3u8"
#EXT-X-MEDIA:TYPE=AUDIO,GROUP-ID="audio1-b",NAME="FRA",DEFAULT=YES,AUTOSELECT=YES,LANGUAGE="FRA",URI="https://hostname/hls/live/XXXXXX-b/streamname/stream05/streamPlaylist.m3u8"

#EXT-X-MEDIA:TYPE=SUBTITLES,GROUP-ID="subs",NAME="fra",DEFAULT=YES,AUTOSELECT=YES,LANGUAGE="fra",CHARACTERISTICS="public.accessibility.describes-music-and-sound",URI="https://hostname/hls/live/XXXXXX/streamname/stream108/streamPlaylist.m3u8"
#EXT-X-MEDIA:TYPE=SUBTITLES,GROUP-ID="subs-b",NAME="fra",DEFAULT=YES,AUTOSELECT=YES,LANGUAGE="fra",CHARACTERISTICS="public.accessibility.describes-music-and-sound",URI="https://hostname/hls/live/XXXXXX-b/streamname/stream108/streamPlaylist.m3u8"

#EXT-X-STREAM-INF:PROGRAM-ID=1,BANDWIDTH=1277113,RESOLUTION=640x360,FRAME-RATE=25.000,AUDIO="audio1",SUBTITLES="subs"
https://hostname/hls/live/XXXXXX/streamname/stream02/streamPlaylist.m3u8
#EXT-X-STREAM-INF:PROGRAM-ID=1,BANDWIDTH=1277113,RESOLUTION=640x360,FRAME-RATE=25.000,AUDIO="audio1-b",SUBTITLES="subs-b"
https://hostname/hls/live/XXXXXX-b/streamname/stream02/streamPlaylist.m3u8
#EXT-X-STREAM-INF:PROGRAM-ID=1,BANDWIDTH=658961,RESOLUTION=384x216,FRAME-RATE=25.000,AUDIO="audio1",SUBTITLES="subs"
https://hostname/hls/live/XXXXXX/streamname/stream01/streamPlaylist.m3u8
#EXT-X-STREAM-INF:PROGRAM-ID=1,BANDWIDTH=658961,RESOLUTION=384x216,FRAME-RATE=25.000,AUDIO="audio1-b",SUBTITLES="subs-b"
https://hostname/hls/live/XXXXXX-b/streamname/stream01/streamPlaylist.m3u8

See also the new talk in WWDC 2021 - "Improve global streaming availability with HLS Content Steering", which I believe is available on Wednesday 2021-06-09

0