MediaTailor player variables for ADS requests
AWS Elemental MediaTailor sends data received from the player to the ADS when you configure
            AWS Elemental MediaTailor to specify player_params.<query_parameter_name>
            variables in the template ADS URL. For example, if the player sends a query parameter
            named user_id in its request to MediaTailor, to pass that data in the ADS
            request, include [player_params.user_id] in the ADS URL configuration. 
This allows you to control the query parameters that are included in the ADS request. Typically, you add a special query parameter that the ADS recognizes to the ADS request URL and provide key-value pairs as the value of the parameter.
The examples used in the following procedure use the following key-value pairs:
- 
                param1 with a value of value1: 
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                param2 with a value of value2: 
To add query parameters as key-value pairs
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                In AWS Elemental MediaTailor, configure the ADS request template URL to reference the parameters. The following URL shows the inclusion of the example parameters: https://my.ads.com/path?param1=[player_params.param1]¶m2=[player_params.param2]
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                (Optional) For server-side ad-tracking reporting, URL-encode the key-value pairs on the player. When MediaTailor receives the session initialization request, it URL-decodes the values once before substituting them into the ADS request URL. NoteIf your ADS requires a URL-encoded value, URL-encode the value twice on the player. This way, the decoding done by MediaTailor results in a once-encoded value for the ADS. For example, if the decoded representation of the values sent to the ADS is param1=value1:¶m2=value2:, then the URL-encoded representation isparam1=value1%3A¶m2=value2%3A.
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                In the session initialization call from the player, pass the key-value pairs to MediaTailor as the value of a single query parameter. The following example calls provide the example key-value pairs for server- and client-side ad tracking reporting. - 
                        Example requests for server-side ad-tracking reporting - using URL-encoded pairs HLS: <master>.m3u8?ads.param1=value1%3A&ads.param2=value2%3ADASH: <manifest>.mpd?ads.param1=value1%3A&ads.param2=value2%3A
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                        Example request for client-side ad-tracking reporting - with no URL-encoding HLS: POST <master>.m3u8 { "adsParams": { "param1": "value1:", "param2": "value2:" } }DASH: POST <manifest>.mpd { "adsParams": { "param1": "value1:", "param2": "value2:" } }
 
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For server-side reporting, MediaTailor decodes the parameters when the player request is received. For client-side reporting, it doesn't alter the parameters received in the JSON payload. MediaTailor sends the following request to the ADS:
https://my.ads.com/<path>?param1=value1:¶m2=value2:In this way, the param1 and param2 key-value pairs are
            included as first-class query parameters in the ADS request.