[5th Ed] Possible errors in example MPD Patch Document

[asrashley]

In clause G.21 of ISO/IEC 23009-1:2022 it has an example of an MPD Patch document.

I think there might be three errors in this example:

• The replace element for the patch location uses selector /MPD/PatchLocation[0] however XPath indexes start at one not zero. See https://www.w3.org/TR/xpath20/#abbrev for examples of the abbreviated index syntax in XPath.
• The add element for the first adaptation set uses selector /MPD/Period[@id='1588435200']/AdaptationSet[@id='1']/SegmentTemplate/SegmentTimeline. However clause 5.15.3.4 states that "All other elements shall be addressed by position, e.g. SegmentTemplate[1]." As neither SegmentTemplate nor SegmentTimeline is listed as one of the special cases for the element addressing restrictions, I think it would need to adhere to the "shall be addressed by position" rule.
• The add element for the second adaptation set uses selector /MPD/Period[@id='1588435200']/AdaptationSet[@id='2']/SegmentTemplate/SegmentTimeline also appears to be in conflict with clause 5.15.3.4.

If my reading of the normative text in the 5th ed DIS and the XPath specification is correct, I think the example should be:

<?xml version="1.0" encoding="UTF-8" standalone="yes"?>
<Patch
 xmlns="urn:mpeg:dash:schema:mpd-patch:2020"
 xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
 xsi:schemaLocation="urn:mpeg:dash:schema:mpd-patch:2020 DASH-MPD-PATCH.xsd"
 mpdId="live-stream"
 originalPublishTime="2020-05-13T05:34:06+00:00"
 publishTime="2020-05-13T05:34:28.601Z">
 <replace sel="/MPD/@publishTime">2020-05-13T05:34:28.601Z</replace>
 <replace sel="/MPD/PatchLocation[1]">
 <PatchLocation ttl="60">live-stream/patch.mpd?publishTime=2020-05-13T05%3A34%3A28.601Z</PatchLocation>
 </replace>
 <add sel="/MPD/Period[@id='1588435200']/AdaptationSet[@id='1']/SegmentTemplate[1]/SegmentTimeline[1]">
 <S d="360360" r="6" t="5494659049"/>
 </add>
 <add sel="/MPD/Period[@id='1588435200']/AdaptationSet[@id='2']/SegmentTemplate[1]/SegmentTimeline[1]">
 <S d="360960" t="5494660288"/>
 <S d="359040"/>
 <S d="360960" r="1"/>
 <S d="359040"/>
 <S d="360960" r="1"/>
 </add>
</Patch>