Time-shifting parameters for manifest requests - AWS Elemental MediaTailor
Time delayStart timeStart program

Time-shifting parameters for manifest requests

This section lists the parameters for time-shifting manifest requests.

To use this functionality, follow the steps in Enable time-shifted viewing.

Time delay

You can specify a duration in seconds for MediaTailor to delay when content is available to players. The minimum is 0 seconds, and the maximum is the maximum time delay that you have configured for the channel.

Use the aws.mediatailor.channel.timeDelay parameter to redefine the live point and make content available later than when it appears in your channel’s schedule. With a 60-second time delay, content that appears in MediaTailor’s schedule at 12:20 is not available until 12:21. Likewise, if you are serving content across time zones, you can set a time delay equal to the difference to make content available at, for example, 8:00 local time.

To supply a time delay to a manifest request, include aws.mediatailor.channel.timeDelay as a query parameter.

Example time delay

https://<some prefix>.channel-assembly.mediatailor.us-west-2.amazonaws.com/v1/channel/ExampleChannel/index_dash.mpd?aws.mediatailor.channel.timeDelay=901

Start time

You can specify a timestamp from which to start playback using the aws.mediatailor.channel.startTime parameter. The start time must be specified in one of the following formats:

  • ISO 8601 dates, such as 2017-08-18T21:18:54+00:00

  • POSIX (or Epoch) time, such as 1503091134

When provided with a start time, MediaTailor responds with a sliding-window manifest, as if the player had requested the initial manifest at the specified start time. For example, a viewer who starts watching a channel at 2023-10-25T14:00:00 and provides an aws.mediatailor.channel.startTime of 2023-10-25T12:00:00 sees the same content as a viewer who starts watching the same channel at 2023-10-25T12:00:00 with no start time specified. On channels with the LINEAR playback mode, the last segment in the manifest window is the segment that overlaps with the time 10 seconds before the time that the request is made. In addition, players maintain a buffer between the playback point and the end of the manifest window. Therefore, playback does not start exactly with the content scheduled for the specified start time.

The delay that results from the specified start time must be at least 0 and must be no greater than the maximum time delay that you configured for the channel.

Example start time

https://<some prefix>.channel-assembly.mediatailor.us-west-2.amazonaws.com/v1/channel/ExampleChannel/index_dash.mpd?aws.mediatailor.channel.startTime=2017-12-19T13:00:28-08:00

Start program

You can specify a program from which playback should start using the aws.mediatailor.channel.startProgram parameter. Acceptable values are the names of programs whose start times fall within the the maximum time delay that you configured for the channel from the end of the manifest window.

When provided with a start program, MediaTailor indicates to players the exact point at which playback should start.

  • For HLS outputs, MediaTailor chooses a delay such that the first segment of the start program is 29 seconds from the end of the manifest window, and uses an EXT-X-START tag in the primary manifest to indicate that the player should start playback with the segment that is 29 seconds from the end of the manifest window.

  • For DASH outputs, MediaTailor chooses a delay based on the suggested presentation delay that you have configured for your output. If your output has a non-zero suggested presentation delay, MediaTailor chooses a delay where the duration between the start of the first segment of the start program and the wall clock time that MediaTailor receives the request is equal to the output’s suggested presentation delay. Otherwise, MediaTailor chooses a delay where the first segment of the start program is 29 seconds from the end of the manifest window. For the best results, we recommend that you configure your output to have a suggested presentation delay that is at least three times the maximum segment duration on your start program, plus 10 seconds.

Players do not necessarily obey MediaTailor’s suggestions, and the point at which playback starts may vary slightly depending on what player you use and how you configure it. We recommend that you test your channel with a start program parameter in your player and, if necessary, make adjustments to your player’s configuration so that it starts playback at the first segment of the start program.

Example start program

https://<ome prefix>.channel-assembly.mediatailor.us-west-2.amazonaws.com/v1/channel/ExampleChannel/index_dash.mpd?aws.mediatailor.channel.startProgram=SuperBowlLVII