Audio/Video Out of Sync

[Jim web]

In article <55ad6f4cbbweb at audiomisc.co.uk>, Jim web
<web at audiomisc.co.uk>
wrote:

> I have had some more info. I'm just checking what I'm allowed to pass
> on! Once that's clear I'll do so. But the people I am talking to may not
> know programme-specific details.

OK, I can pass this on. Hope it helps, but I confess I don't understand all
of it! So it may already be well known. I think the basic idea is that we
may need to avoid some old 'legacy' arrangements.

The response was...


Anything served from akamaihd.net is from our legacy platform.
That means Akamai are doing the media segmenting and manifest generation.
These services are deprecated.

Without giving too much away I can tell you that the 'current' HLS is
served from hosts:

llnwd.net - Limelight
edgesuite.net - Akamai

Manifests served from those hosts will look like:

#EXTM3U
#EXT-X-VERSION:2
## Created with Unified Streaming Platform(version=1.7.18)

# variants
#EXT-X-STREAM-INF:BANDWIDTH=1013000,CODECS="mp4a.40.2,avc1.4D401E",RESOLUTI
ON=704x396,FRAME-RATE=25
vf_b07nsx00_2e5666d8-dfa3-45e9-a812-315abab948f7.ism.hlsv2-audio=128000-vid
eo=827000.m3u8
#EXT-X-STREAM-INF:BANDWIDTH=1800000,CODECS="mp4a.40.2,avc1.64001F",RESOLUTI
ON=704x396,FRAME-RATE=50
vf_b07nsx00_2e5666d8-dfa3-45e9-a812-315abab948f7.ism.hlsv2-audio=128000-vid
eo=1570000.m3u8
#EXT-X-STREAM-INF:BANDWIDTH=3117000,CODECS="mp4a.40.2,avc1.64001F",RESOLUTI
ON=960x540,FRAME-RATE=50
vf_b07nsx00_2e5666d8-dfa3-45e9-a812-315abab948f7.ism.hlsv2-audio=128000-vid
eo=2812000.m3u8
#EXT-X-STREAM-INF:BANDWIDTH=5510000,CODECS="mp4a.40.2,avc1.640020",RESOLUTI
ON=1280x720,FRAME-RATE=50
vf_b07nsx00_2e5666d8-dfa3-45e9-a812-315abab948f7.ism.hlsv2-audio=128000-vid
eo=5070000.m3u8


Which gives you 4 bitrate profiles in an ABR (adaptive bitrate) set.
Note the "Created with Unified Streaming Platform" comment which shows we
(the BBC) and not Akamai have segmented and packaged the content in-house.

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