[SOLVED] Why this dash manifest keeps the player stuck until streams are downloaded?

Why this dash manifest keeps the player stuck until streams are downloaded?

I have this manifest file below . The issue is that the player waits for the streams to download completely before to start playing which is bad for the user experience. Any idea how to fix it? I expected the player to start range requests and feed media source with partial requests instead to wait for the streams to completely download.

<MPD xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns="urn:mpeg:dash:schema:mpd:2011" xmlns:xlink="http://www.w3.org/1999/xlink" xsi:schemaLocation="urn:mpeg:DASH:schema:MPD:2011 http://standards.iso.org/ittf/PubliclyAvailableStandards/MPEG-DASH_schema_files/DASH-MPD.xsd" profiles="urn:mpeg:dash:profile:isoff-live:2011" type="static" mediaPresentationDuration="PT30M67.6S" minBufferTime="PT2S">
<ProgramInformation></ProgramInformation>
<Period id="0" start="PT0.0S">
<AdaptationSet id="0" contentType="video" segmentAlignment="true" bitstreamSwitching="true" lang="und">
<Representation id="0" mimeType="video/webm" codecs="vp9" bandwidth="770153" width="854" height="480" frameRate="23421/1000">
<BaseURL>https://liveradio.s3.eu-central-1.amazonaws.com/video.webm</BaseURL>
<SegmentList duration="1840613" startNumber="1">
<Initialization range="0-219"/>
<SegmentURL indexRange="220-6592"/>
</SegmentList>
</Representation>
</AdaptationSet>
<AdaptationSet id="1" contentType="audio" segmentAlignment="true" bitstreamSwitching="true" lang="und">
<Representation id="1" mimeType="audio/webm" codecs="opus" bandwidth="115412" audioSamplingRate="48000">
<AudioChannelConfiguration schemeIdUri="urn:mpeg:dash:23003:3:audio_channel_configuration:2011" value="2"/>
<BaseURL>https://liveradio.s3.eu-central-1.amazonaws.com/audio.webm</BaseURL>
<SegmentList duration="1840641" startNumber="1">
<Initialization range="0-258"/>
<SegmentURL  indexRange="259-3444"/>
</SegmentList>
</Representation>
</AdaptationSet>
</Period>
</MPD>

Solution

You seem to be using a mix of the DASH 'live' profile approach and the 'on-demand' profile one - you can see the profile in the profiles="urn:mpeg:dash:profile:isoff-live:2011" at the top of your manifest.

At a very high level the difference is:

'live' profile manifests contain a list of urls for each segment to be downloaded.
'on-demand' profile manifests contain a URL to a file and an index to where the segments can be found in the file, so the client can download chunks as it wants.

DASH is a complex specification and it may be that some players will accept some mixes of profiles and others not, and not all players support all features - for example Shaka player claims not to support 'indexRange' (or did in 2017: https://github.com/google/shaka-player/issues/765)