# MediaTailor and MediaPackage time-shifted viewing integration
<a name="mediapackage-integration-param"></a>

AWS Elemental MediaTailor can pass time-shifted viewing parameters to MediaPackage origins to enable startover and catch-up viewing functionality. This integration allows viewers to start watching live content from earlier points in time.

**MediaPackage time-shifted viewing parameters**  
MediaPackage supports the following time-shifted viewing parameters that can be passed through MediaTailor:
+ `start`: Epoch or ISO 8601 timestamp defining the beginning of the time-shifted manifest
+ `end`: Epoch or ISO 8601 timestamp defining the end of the time-shifted manifest
+ `time_delay`: Delay content availability by specified seconds
+ `manifest_window_seconds`: Request a manifest shorter than the configured window

**Example MediaTailor session initialization with MediaPackage time-shifted parameters**  
The following example shows how to initialize a session with time-shifted viewing parameters:  

```
GET /v1/master/123456789/originId/index.m3u8?start=2024-08-26T10:00:00Z&end=2024-08-26T11:00:00Z
```
Or using explicit session initialization:  

```
POST /v1/session/123456789/originId/index.m3u8
{
    "adsParams": {
        "param1": "value1"
    }
}
```
With additional query parameters:  

```
?start=2024-08-26T10:00:00Z&end=2024-08-26T11:00:00Z
```

**Parameter behavior during sessions**  
Time-shifted viewing parameters have specific behavior characteristics:
+ **Session initialization:** Parameters are processed when the session is created
+ **Parameter persistence:** Parameters remain associated with the session throughout playback
+ **Immutable after initialization:** Parameters cannot be changed during an active session
+ **New session required:** To modify time-shift windows, create a new session with updated parameter values

**MediaPackage startover window requirements**  
For time-shifted viewing to work with MediaPackage, ensure the following:

1. Configure a startover window on your MediaPackage endpoint (up to 24 hours)

1. Ensure your CDN forwards the necessary query parameters to MediaPackage

1. Use consistent playback windows across player sessions for better CDN caching

1. Verify that start and end times fall within the configured startover window

**Important**  
When using time-shifted viewing, use consistent playback windows across player sessions rather than generating unique start or end times for each viewer. This yields better caching at the CDN and avoids potential throttling.

For complete information about MediaPackage time-shifted viewing configuration and parameters, see [Time-shifted viewing with AWS Elemental MediaPackage](https://docs.aws.amazon.com/mediapackage/latest/ug/time-shifted.html) in the *AWS Elemental MediaPackage User Guide*.