MediaTailor DASH implicit session initialization - AWS Elemental MediaTailor

MediaTailor DASH implicit session initialization

AWS Elemental MediaTailor creates a session for the client and redirects it with query parameters when the client makes a manifest request without a session. The following example shows this request format:

GET /v1/dash/111122223333/originId/index.mpd?manifest.test=123&other=456

MediaTailor creates a session for the client and redirects it with the query parameters:

/v1/dash/111122223333/originId/index.mpd?sessionId=session&test=123
Parameter application in DASH

The DASH manifest response includes the query parameters in various locations, including content segments, ad segments, and initialization URLs. MediaTailor applies parameters to the following:

  • DASH manifest Location elements

  • SegmentTemplate initialization attributes

  • SegmentTemplate media attributes

  • Content segment URLs

  • Ad segment URLs

When the client makes the request, MediaTailor responds with a DASH manifest similar to the following example. The first period is a content period, so MediaTailor doesn't insert the manifest query parameter there. In the second period, which is an ad period, MediaTailor inserts the manifest query parameter into the SegmentTemplate element's initialization attribute and media attribute. The Location element also has the manifest query parameters.

<?xml version="1.0" encoding="UTF-8"?>
<MPD availabilityStartTime="2018-07-27T09:48:23.634000+00:00" id="201" minBufferTime="PT30S" minimumUpdatePeriod="PT15S" profiles="urn:mpeg:dash:profile:isoff-live:2011" publishTime="2023-02-14T23:37:43" suggestedPresentationDelay="PT25.000S" timeShiftBufferDepth="PT56.997S" type="dynamic" xmlns="urn:mpeg:dash:schema:mpd:2011" xmlns:scte35="urn:scte:scte35:2013:xml" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="urn:mpeg:dash:schema:mpd:2011 http://standards.iso.org/ittf/PubliclyAvailableStandards/MPEG-DASH_schema_files/DASH-MPD.xsd">
    <BaseURL>https://origin.com/contentSegments/</BaseURL>
    <Location>https://mediatailor.com/v1/dash/111122223333/originId/index.mpd?test=123&aws.sessionId=session</Location>
    <Period duration="PT29.963S" id="28737823" start="PT143732873.178S">
        <AdaptationSet bitstreamSwitching="true" mimeType="video/mp4" segmentAlignment="true" startWithSAP="1" subsegmentAlignment="true" subsegmentStartsWithSAP="1">
            <Representation bandwidth="2200000" codecs="avc1.640029" frameRate="30000/1001" height="540" id="1" width="960">
                <SegmentTemplate initialization="index_video_7_0_init.mp4?m=1611174111" media="index_video_7_0_$Number$.mp4?m=1611174111" presentationTimeOffset="4311986195351" startNumber="28737828" timescale="30000">
                    <SegmentTimeline>
                        <S d="180180" t="4311986911066"/>
                        <S d="3003" t="4311987091246"/>
                    </SegmentTimeline>
                </SegmentTemplate>
            </Representation>
        </AdaptationSet>
    </Period>
    <Period id="28737829_1" start="PT39925H48M23.141S">
        <BaseURL>https://mediatailor.com/v1/dashsegment/111122223333/originId/session/28737829/28737829_1/</BaseURL>
        <AdaptationSet bitstreamSwitching="false" frameRate="30000/1001" mimeType="video/mp4" segmentAlignment="true" startWithSAP="1" subsegmentAlignment="true" subsegmentStartsWithSAP="1">
            <SegmentTemplate startNumber="1" timescale="90000"/>
            <Representation bandwidth="2200000" codecs="avc1.64001f" height="540" id="1" width="960">
                <SegmentTemplate initialization="asset_540_2_0init.mp4?test=123" media="asset_540_2_0_$Number%09d$.mp4?test=123" startNumber="1" timescale="90000">
                    <SegmentTimeline>
                        <S d="180180" r="6" t="0"/>
                        <S d="87087" t="1261260"/>
                    </SegmentTimeline>
                </SegmentTemplate>
            </Representation>
        </AdaptationSet>
    </Period>
</MPD>