Multi-period DASH in AWS Elemental MediaPackage - AWS Elemental MediaPackage
How it works

Multi-period DASH in AWS Elemental MediaPackage

The ability to insert multiple periods in DASH manifests for both VOD and live is available in AWS Elemental MediaPackage.

A period is a chunk of content in the DASH manifest, defined by a start time and duration. By default, the entire manifest is contained in one period but MediaPackage can partition the DASH manifest into multiple periods to indicate boundaries between ads and the main content. For example, if you're using MediaPackage with a downstream ad service such as AWS Elemental MediaTailor, choose Trigger new period on ads on the MPEG-DASH endpoint in MediaPackage. This option tells MediaPackage that the DASH manifest is to be formatted with multiple periods.

How multi-period DASH works

To use the multi-period DASH feature, the input to MediaPackage must have SCTE-35 ad marker messages. These messages inform MediaPackage of where to create period boundaries. This is how MediaPackage processes those messages:

  1. MediaPackage detects the SCTE-35 messages from the input source.

  2. Using the attributes of the SCTE-35 messages, MediaPackage calculates where the boundaries are between the end of the main content and the ads. This calculation is (scte35 ptsAdjustment + scte35 ptsTime) / (EventStream timescale).

    In the following example, the period starts at 44.075 seconds because (183003 + 3783780) / 90000 = 44.075:

    <Period start="PT44.075S" id="21">
    <EventStream timescale="90000" schemeIdUri="urn:scte:scte35:2013:xml">
      <Event>
        <scte35:SpliceInfoSection protocolVersion="0" ptsAdjustment="183003" tier="4095">
          <scte35:SpliceInsert spliceEventId="1000" spliceEventCancelIndicator="false" outOfNetworkIndicator="true" spliceImmediateFlag="false" uniqueProgramId="7" availNum="1" availsExpected="4">
            <scte35:Program><scte35:SpliceTime ptsTime="3783780"/></scte35:Program>
          </scte35:SpliceInsert>
        </scte35:SpliceInfoSection>
      </Event>
    </EventStream>
     .
     .
</Period>

  3. MediaPackage inserts the EventStream, Event, and scte35 tags with additional information into the manifest and surrounds the ad period with a Period tag, as shown in the preceding example. MediaPackage groups all adaptation sets before the first ad period into a period, and any subsequent adaptation sets after the ad are grouped into a period, until the next SCTE-35 marker. Here is a complete manifest example with multiple periods. It uses SpliceInsert SCTE-35 ad markers:

    <?xml version="1.0" encoding="utf-8"?>
<MPD>
  <Period start="PT0.000S" id="0" duration="PT44.075S">
    <AdaptationSet mimeType="video/mp4" segmentAlignment="true" subsegmentAlignment="true" startWithSAP="1" subsegmentStartsWithSAP="1" bitstreamSwitching="true">
      <Representation id="1" width="960" height="540" frameRate="30000/1001" bandwidth="1000000" codecs="avc1.4D401F">
        <SegmentTemplate timescale="30000" media="index_video_1_0_$Number$.mp4?m=1528413503" initialization="index_video_1_0_init.mp4?m=1528413503" startNumber="6" presentationTimeOffset="0">
          <SegmentTimeline>
            <S t="361301" d="60060" r="15"/>
          </SegmentTimeline>
        </SegmentTemplate>
      </Representation>
    </AdaptationSet>
    <AdaptationSet mimeType="audio/mp4" segmentAlignment="0" lang="eng">
      <Representation id="2" bandwidth="96964" audioSamplingRate="48000" codecs="mp4a.40.2">
        <SegmentTemplate timescale="48000" media="index_audio_2_0_$Number$.mp4?m=1528413503" initialization="index_audio_2_0_init.mp4?m=1528413503" startNumber="6" presentationTimeOffset="0">
          <SegmentTimeline>
            <S t="578305" d="96256" r="3"/>
            <S t="963329" d="95232"/>
            <S t="1058561" d="96256" r="5"/>
            <S t="1636097" d="95232"/>
            <S t="1731329" d="96256" r="3"/>
          </SegmentTimeline>
        </SegmentTemplate>
      </Representation>
    </AdaptationSet>
  </Period>
  <Period start="PT44.075S" id="21">
    <EventStream timescale="90000" schemeIdUri="urn:scte:scte35:2013:xml">
      <Event>
        <scte35:SpliceInfoSection protocolVersion="0" ptsAdjustment="183003" tier="4095">
          <scte35:SpliceInsert spliceEventId="1000" spliceEventCancelIndicator="false" outOfNetworkIndicator="true" spliceImmediateFlag="false" uniqueProgramId="7" availNum="1" availsExpected="4">
            <scte35:Program><scte35:SpliceTime ptsTime="3783780"/></scte35:Program>
          </scte35:SpliceInsert>
        </scte35:SpliceInfoSection>
      </Event>
    </EventStream>
    <AdaptationSet mimeType="video/mp4" segmentAlignment="true" subsegmentAlignment="true" startWithSAP="1" subsegmentStartsWithSAP="1" bitstreamSwitching="true">
      <Representation id="1" width="960" height="540" frameRate="30000/1001" bandwidth="1000000" codecs="avc1.4D401F">
        <SegmentTemplate timescale="30000" media="index_video_1_0_$Number$.mp4?m=1528413503" initialization="index_video_1_0_init.mp4?m=1528413503" startNumber="22" presentationTimeOffset="1322261">
          <SegmentTimeline>
            <S t="1322261" d="60060" r="13"/>
          </SegmentTimeline>
        </SegmentTemplate>
      </Representation>
    </AdaptationSet>
    <AdaptationSet mimeType="audio/mp4" segmentAlignment="0" lang="eng">
      <Representation id="2" bandwidth="96964" audioSamplingRate="48000" codecs="mp4a.40.2">
        <SegmentTemplate timescale="48000" media="index_audio_2_0_$Number$.mp4?m=1528413503" initialization="index_audio_2_0_init.mp4?m=1528413503" startNumber="22" presentationTimeOffset="2115617">
          <SegmentTimeline>
            <S t="2116353" d="96256"/>
            <S t="2212609" d="95232"/>
            <S t="2307841" d="96256" r="5"/>
            <S t="2885377" d="95232"/>
            <S t="2980609" d="96256" r="4"/>
          </SegmentTimeline>
        </SegmentTemplate>
      </Representation>
    </AdaptationSet>
  </Period>
</MPD>

    If your input has TimeSignal SCTE-35 ad markers instead of SpliceInsert, the EventStream within the ad period looks like this:

    <EventStream timescale="90000" schemeIdUri="urn:scte:scte35:2013:xml">
  <Event>
    <scte35:SpliceInfoSection protocolVersion="0" ptsAdjustment="183265" tier="4095">
      <scte35:TimeSignal>
        <scte35:SpliceTime ptsTime="1350000"/>
      </scte35:TimeSignal>
      <scte35:SegmentationDescriptor segmentationEventId="1073741825" segmentationEventCancelIndicator="false" segmentationDuration="450000">
        <scte35:DeliveryRestrictions webDeliveryAllowedFlag="false" noRegionalBlackoutFlag="true" archiveAllowedFlag="true" deviceRestrictions="3"/>
        <scte35:SegmentationUpid segmentationUpidType="1" segmentationUpidLength="3" segmentationTypeId="48" segmentNum="0" segmentsExpected="0">012345</scte35:SegmentationUpid>
      </scte35:SegmentationDescriptor>
    </scte35:SpliceInfoSection>
  </Event>
</EventStream>

    MediaPackage also embeds scte35:SpliceInsert messages as metadata in the individual video segments.

If you're using a downstream ad service, that service looks for the SCTE-35 markers in the manifest that MediaPackage provides and inserts ads based on those markers.