Issue with sequence of elements in the MPD

[ypo]

MPD elements are not ordered based the <xs:sequence> of the DASH schema.
The results is that MPDs generated by this library are not passing the XML Schema validation

For example, the following MPD Instance :

<?xml version="1.0" encoding="UTF-8"?>
<MPD type="dynamic"
  xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
  xmlns:cenc="urn:mpeg:cenc:2013"
  xmlns:xlink="http://www.w3.org/1999/xlink"
  xmlns:dvb="urn:dvb:dash-extensions:2014-1"
  xmlns="urn:mpeg:dash:schema:mpd:2011" xsi:schemaLocation="urn:mpeg:dash:schema:mpd:2011 DASH-MPD.xsd" profiles="urn:mpeg:dash:profile:isoff-live:2011" minBufferTime="PT2S" minimumUpdatePeriod="PT2S" timeShiftBufferDepth="PT1M0S" publishTime="2024-11-12T11:49:06Z" availabilityStartTime="1970-01-01T00:00:02.664019486Z">
  <Period id="P0" start="PT0S">
    <AdaptationSet contentType="video" sar="1:1" scanType="progressive" segmentAlignment="true" mimeType="video/mp4" maxWidth="1280" maxHeight="720" frameRate="50" maxFrameRate="50" startWithSAP="1">
      <Role schemeIdUri="urn:mpeg:dash:role:2011" value="main"/>
      <SegmentTemplate initialization="$RepresentationID$/init.mp4" media="$RepresentationID$/$Number$.m4s" startNumber="0" duration="200" timescale="100"/>
      <Representation id="HD" codecs="avc1.640020" bandwidth="6281004" width="1280" height="720"/>
      <Representation id="SD" codecs="avc1.64001f" bandwidth="1507176" width="854" height="480"/>
    </AdaptationSet>
    <AdaptationSet contentType="audio" lang="eng" segmentAlignment="true" audioSamplingRate="48000" mimeType="audio/mp4" codecs="mp4a.40.2" startWithSAP="1">
      <Role schemeIdUri="urn:mpeg:dash:role:2011" value="main"/>
      <SegmentTemplate initialization="$RepresentationID$/init.mp4" media="$RepresentationID$/$Number$.m4s" startNumber="0" duration="96000" timescale="48000"/>
      <AudioChannelConfiguration schemeIdUri="urn:mpeg:mpegB:cicp:ChannelConfiguration" value="2"/>
      <Representation id="audio" bandwidth="101673"/>
    </AdaptationSet>
  </Period>
  <UTCTiming schemeIdUri="urn:mpeg:dash:utc:http-iso:2014" value="http://dvb.gw/time?iso&amp;ms"/>
</MPD>

Is generating the following error when validating with DASH-MPD.xsd :

Element '{urn:mpeg:dash:schema:mpd:2011}AudioChannelConfiguration': This element is not expected. Expected is ( {urn:mpeg:dash:schema:mpd:2011}Representation ).

[emarsden]

Indeed, most MPD consumers don't care about the order of elements, but it should be fixed.

[ypo]

This is correct, most players don't care.
However I'm using this project to manipulate and serialize MPDs, generated MPDs are passing through validators before going on production and they are rejected.
I'd be very happy if it can be fixed 👍

[emarsden]

There is some initial support for this in HEAD. I don't currently have fully satisfactory test support in place (in part because many manifests in the wild don't appear to be valid), so please report and remaining problems.

[ypo]

I moved to the HEAD and I confirm that the generated MDPs are now valid against the schema .
However I'm using only a very limited subset of DASH, but I'll report if I see a problem.