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HLS v3 audio only

yvettema@cisco.com

Total Posts:
Joined: March 09, 2016

Hi,

We are trying to generate an HLS v3 variant playlist which includes an audio only playlist together with several video playlists.

According to the spec, we should just list all video playlists for the variant generation and include the one which we want to generate audio only for twice. However this doesn't seem to work, as it just generates the variant with the video playlist twice:

- mp4split --package-hls -o variant.m3u8 video1.m3u8 video2.m3u8 video3.m3u8 video3.m3u8

generates

#EXTM3U
#EXT-X-MEDIA:TYPE=SUBTITLES,GROUP-ID="subs",NAME="English",DEFAULT=YES,FORCED=NO,URI="c0_ABCDEF123456_clear/c0_ABCDEF123456_clear.m3u8",LANGUAGE="en"
#EXT-X-VERSION:1
## Created with Unified Streaming Platform(version=1.7.17)
#EXT-X-STREAM-INF:BANDWIDTH=722000,AVERAGE-BANDWIDTH=531000,CODECS="mp4a.40.2,avc1.4D4029",RESOLUTION=852x480,SUBTITLES="subs"
v0_ABCDEF123456_clear/v1_ABCDEF123456_clear.m3u8
#EXT-X-STREAM-INF:BANDWIDTH=989000,AVERAGE-BANDWIDTH=646000,CODECS="mp4a.40.2,avc1.4D4029",RESOLUTION=852x480,SUBTITLES="subs"
v1_ABCDEF123456_clear/v2_ABCDEF123456_clear.m3u8
#EXT-X-STREAM-INF:BANDWIDTH=1628000,AVERAGE-BANDWIDTH=1011000,CODECS="mp4a.40.2,avc1.4D4029",RESOLUTION=1280x720,SUBTITLES="subs"
v2_ABCDEF123456_clear/v3_ABCDEF123456_clear.m3u8
#EXT-X-STREAM-INF:BANDWIDTH=1628000,AVERAGE-BANDWIDTH=1011000,CODECS="mp4a.40.2,avc1.4D4029",RESOLUTION=1280x720,SUBTITLES="subs"
v2_ABCDEF123456_clear/v3_ABCDEF123456_clear.m3u8

Also when extracting the audio with --track audio and then adding it to the variant I get an error saying STREAM-INF is not compatible with MEDIA tags. (mixing hlsv3 and hlsv4 I suppose).

Can you point me in the right direction as to how I can generate HLSv3 variant playlists with an audio only playlist attached? It is very important it remains HLSv3, I can't have demuxed audio tracks for backwards compatibility.

Thanks and kind regards,
Yvette

Tags: hls, V3, AUDIO, AUDIO-ONLY
Posted on September 30, 2016 at 12:41 AM

Dirk

Total Posts:
Joined: June 23, 2010

Re: HLS v3 audio only

Hi,

Could you perhaps repost to support[at]unified-streaming.com?

Posted on September 30, 2016 at 8:43 AM