# How input prepare actions work
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You can set up an action to prepare an input that is associated with an immediate input switch, in order to reduce the delay that occurs when MediaLive performs the switch.

The input must already be attached to the channel. However, there is no requirement for the input switch for this input to already exist in the schedule. For example, input X must be *attached *to the channel. You can create action A to prepare input X and later on you can create action B to switch to input X. Or you can create action B and then create action A.

Before you add input prepare actions to the schedule, read [Preparing inputs in AWS Elemental MediaLive](feature-prepare-input.md).

**Input prepare with fixed start**  
When you create the action, include a start time. The start time for the action must be at least 15 seconds before the start time of the associated input switch, but not more than 14 days in the future. After that cutoff, MediaLive rejects the request to create the action. 

After you have created the action, the action sits in the schedule. Approximately 15 seconds before the start time of the prepare action, the schedule passes the action to the channel. The channel starts preparing the input.

**Input prepare with immediate start**  
When you create the action, you set the start type to *immediate*. 

The schedule immediately passes the action to the channel. The channel immediately starts the prepare.

**Input prepare with follow start**  
When you create the action, you specify the input switch action that you want this action to follow. That *reference action* must be an input switch.

The input for the reference action must have a source end behavior of *Continue*. To find the **Source end behavior** field, go to the **Create channel** page, find the input in the **Input attachment** list, and then find **General input settings**. 

After you create the action, the action waits in the schedule. Just before the reference action is due to finish, the schedule passes the action to the channel. As soon as the current input has finished, the channel switches to the new input.