# DASH ad markers
<a name="dash-ad-markers"></a>

MediaTailor 

AWS Elemental MediaTailor uses SCTE-35 cue-out markers to identify ad avails in the DASH manifest using the following logic: 
+ **Multi-period DASH**: MediaTailor inserts ads for the first `Event` in each `Period` that contains either `SpliceInsert` or `TimeSignal` cue-out markers. MediaTailor ignores additional `Event` markers in the `Period`.
+ **Single-period DASH**: MediaTailor inserts ads each `Event` in the `Period` that contains either `SpliceInsert` or `TimeSignal` cue-out markers.

By default, AWS Elemental MediaTailor manages DASH manifests as multi-period manifests. You can change your configuration to handle single-period DASH manifests from your origin server. For information, see [Creating an MediaTailor playback configuration](configurations-create.md).

The following sections provide additional detail about DASH ad marker handling and provides decorated manifests from the origin.

## DASH origin manifest XML requirements
<a name="dash-ad-markers-examples"></a>

Ad markers in DASH manifests from the origin must be formatted properly for MediaTailor to identify ad breaks. The following topics describe these formatting requirements in clear XML.

### `SpliceInsert` in clear XML
<a name="dash-splice-xml"></a>

`SpliceInsert` ad markers in clear XML must contain the following:
+ `EventStream` must have the following attribute: `schemeIdUri=urn:scte:scte35:2013:xml`
+ `Event` must hold `scte35:SpliceInfoSection` 
+ `scte35:SpliceInfoSection` must hold `scte35:SpliceInsert` 
+ `scte35:SpliceInsert` must have the following attribute: `outOfNetworkIndicator="true"`

**Example `SpliceInsert` in XML**  
In the following example, required SCTE markers are in bold.   

```
<Period start="PT444806.040S" id="123586" duration="PT15.000S">
  <EventStream timescale="90000" schemeIdUri="urn:scte:scte35:2013:xml">
    <Event duration="1350000">
      <scte35:SpliceInfoSection protocolVersion="0" ptsAdjustment="180832" tier="4095">
        <scte35:SpliceInsert spliceEventId="4026531855" spliceEventCancelIndicator="false" outOfNetworkIndicator="true" spliceImmediateFlag="false" uniqueProgramId="1" availNum="1" availsExpected="1">
            <scte35:Program><scte35:SpliceTime ptsTime="5672624400"/></scte35:Program>
            <scte35:BreakDuration autoReturn="true" duration="1350000"/>
        </scte35:SpliceInsert>
      </scte35:SpliceInfoSection>
    </Event>
  .
  .
  .
</Period>
```

### `TimeSignal` in clear XML
<a name="dash-signal-xml"></a>

`TimeSignal` ad markers in clear XML must contain the following:
+ `EventStream` must have the following attribute: `schemeIdUri=urn:scte:scte35:2013:xml`
+ `Event` must hold `scte35:SpliceInfoSection`
+ `scte35:SpliceInfoSection` must hold `scte35:TimeSignal`
+ `scte35:SpliceInfoSection` must also hold `scte35:SegmentationDescriptor`
+ `scte35:SegmentationDescriptor` must have the following attribute, where the value is a valid [Cue-out numbers](#dash-signal-xml-values): `segmentationTypeId="{{xx}}"`
+ `scte35:SegmentationDescriptor` must hold `scte35:SegmentationUpid` 
<a name="dash-signal-xml-values"></a>
**Cue-out numbers**  
The following are supported cue-out numbers for the `segmentationTypeId`.


| Segmentation message | segmentationTypeId value | Hexadecimal value | 
| --- | --- | --- | 
| Distributor advertisement end | 51 | 0x51 | 
| Distributor advertisement start | 50 | 0x32 | 
| Distributor placement opportunity end | 55 | 0x37 | 
| Distributor placement opportunity start | 54 | 0x36 | 
| End break | 35 | 0x23 | 
| Provider advertisement end | 49 | 0x31 | 
| Provider advertisement start | 48 | 0x30 | 
| Provider overlay placement opportunity end | 57 | 0x39 | 
| Provider overlay placement opportunity start | 56 | 0x38 | 
| Provider placement opportunity end | 53 | 0x35 | 
| Provider placement opportunity start | 52 | 0x34 | 
| Start break | 34 | 0x22 | 

**Example `TimeSignal` in XML**  
In the following example, required SCTE markers are in bold.   

```
<Period start="PT346530.250S" id="178443" duration="PT61.561S">
  <EventStream timescale="90000" schemeIdUri="urn:scte:scte35:2013:xml">
    <Event duration="5310000">
      <scte35:SpliceInfoSection protocolVersion="0" ptsAdjustment="183003" tier="4095">
        <scte35:TimeSignal>
          <scte35:SpliceTime ptsTime="3442857000"/>
         </scte35:TimeSignal>
        <scte35:SegmentationDescriptor segmentationEventId="1414668" segmentationEventCancelIndicator="false" segmentationDuration="8100000" segmentationTypeId="52" segmentNum="0" segmentsExpected="0">
            <scte35:DeliveryRestrictions webDeliveryAllowedFlag="false" noRegionalBlackoutFlag="false" archiveAllowedFlag="false" deviceRestrictions="3"/>
            <scte35:SegmentationUpid segmentationUpidType="12" segmentationUpidLength="2">0100</scte35:SegmentationUpid>
          </scte35:SegmentationDescriptor>
        </scte35:SpliceInfoSection>
    </Event>
  .
  .
  .
</Period>
```

## DASH origin manifest base64-encoded binary requirements
<a name="dash-base64"></a>

Ad markers in DASH manifests from the origin must be formatted properly for MediaTailor to identify ad breaks. The following topics describe these formatting requirements in base64-encoded binary.

Both `TimeSignal` and `SpliceInsert` ad markers in base64-encoded manifests must contain the following:
+ `EventStream` must have the following attribute: `urn:scte:scte35:2014:xml+bin`
+ `Event` must hold `scte35:Signal`
+ `scte35:Signal` must hold `scte35:Binary` that contains a base64-encoded binary. 

The decoded binary must provide a `splice_info_section` with the same information as what's required for clear XML ad markers.
+ The command type must be either `splice_insert()` or `time_signal()`
+ The additional settings must comply with those described in [`TimeSignal` in clear XML](#dash-signal-xml) and [`SpliceInsert` in clear XML](#dash-splice-xml).

 The decoded binary must provide a `splice_info_section` with the same set of information as the clear XML would provide in a `scte35:SpliceInfoSection` element. The command type must be either `splice_insert()` or `time_signal()`, and the additional settings must comply with those described previously for clear XML delivery. 

The following example shows this option, with the required markers in bold.

```
<Period start="PT444806.040S" id="123586" duration="PT15.000S">
    <EventStream schemeIdUri="urn:scte:scte35:2014:xml+bin" timescale="1">
      <Event presentationTime="1541436240" duration="24" id="29">
        <scte35:Signal xmlns="http://www.scte.org/schemas/35/2016">
          <scte35:Binary>/DAhAAAAAAAAAP/wEAUAAAHAf+9/fgAg9YDAAAAAAAA25aoh</scte35:Binary>
        </scte35:Signal>
      </Event>
      <Event presentationTime="1541436360" duration="24" id="30">
        <scte35:Signal xmlns="http://www.scte.org/schemas/35/2016">
          <scte35:Binary>QW5vdGhlciB0ZXN0IHN0cmluZyBmb3IgZW5jb2RpbmcgdG8gQmFzZTY0IGVuY29kZWQgYmluYXJ5Lg==</scte35:Binary>
        </scte35:Signal>
      </Event>
  .
  .
  .
</Period>
```

The following is the decoded binary for the first event listed in the preceding example. The setting for `splice_command_type` is 5, which indicates `splice_insert`. 

```
{
        "table_id": 252,
        "section_syntax_indicator": false,
        "private_indicator": false,
        "section_length": 33,
        "protocol_version": 0,
        "encrypted_packet": false,
        "encryption_algorithm": 0,
        "pts_adjustment": 0,
        "cw_index": 0,
        "tier": "0xFFF",
        "splice_command_length": 16,
        "splice_command_type": 5,
        "splice_command": {
          "splice_event_id": 448,
          "splice_event_cancel_indicator": false,
          "out_of_network_indicator": true,
          "program_splice_flag": true,
          "duration_flag": true,
          "splice_immediate_flag": false,
          "utc_splice_time": {
            "time_specified_flag": false,
            "pts_time": null
          },
          "component_count": 0,
          "components": null,
          "break_duration": {
            "auto_return": false,
            "duration": {
              "pts_time": 2160000,
              "wall_clock_seconds": 24.0,
              "wall_clock_time": "00:00:24:00000"
            }
          },
          "unique_program_id": 49152,
          "avail_num": 0,
          "avails_expected": 0
        },
        "splice_descriptor_loop_length": 0,
        "splice_descriptors": null,
        "Scte35Exception": {
          "parse_status": "SCTE-35 cue parsing completed with 0 errors.",
          "error_messages": [],
          "table_id": 252,
          "splice_command_type": 5
        }
      }
```