# Enabling ad avail blanking in the output
<a name="enable-ad-avail-blanking"></a>

In a MediaLive channel, you can enable ad avail blanking to blank out the content for an SCTE 35 message that is considered an ad avail (as defined by the ad avail mode in [Getting ready: Set the ad avail mode](getting-ready-set-the-ad-avail-mode.md)).

A similar feature is [blackout](enable-blackout.md).

Blanking involves the following processing:
+ Replace the video content associated with this event with an image that you specify or is with a black image. 
+ Remove the audio that is associated with this event. 
+ Remove the captions that are associated with this event. 

**Comparison to Manifest Decoration and Passthrough**

Ad avail blanking applies to all outputs. You cannot choose to blank out for some outputs (for example, the HLS output) and not blank out for others (for example, the Microsoft Smooth output). It is an all-or-nothing decision. 

Manifest decoration and passthrough have a smaller scope: they apply only to outputs that support these features. 

**Important**  
Be careful not to get into the following situation:  
You do *not* do passthrough.
You do *not* do manifest decoration in a specific output (because they are not supported or because you choose not to).
You do implement blanking
In this situation, there will be no markers for where the blanked content occurs. The only way to identify where this blanking is occurring will be to look for the IDR i-frames that identify where the SCTE 35 message used to be.

**Topics**
+ [Enabling blanking](procedure-to-enable-ad-avail-blanking.md)
+ [Triggers for ad avail blanking](triggers-for-ad-avail-blanking.md)
+ [Ad avail blanking restriction flags](ad-avail-blanking-restriction-flags.md)

# Enabling blanking
<a name="procedure-to-enable-ad-avail-blanking"></a>

Follow this procedure if you want to enable the ad avail blanking feature in a MediaLive channel.

**To enable blanking**

1. In the channel that you are creating, in the navigation pane, choose **General settings**. 

1.  Set the ad avail mode, if you have not already done so. See [Getting ready: Set the SCTE 35 source—segments or manifest](scte35-getting-ready-source.md). The mode identifies which of all possible events are treated as triggers for blanking, which determines [when video is blanked](triggers-for-ad-avail-blanking.md). 

1. Still in **General settings**, in **Avail blanking**, in **State**, choose **Enabled**.

1. In **Avail blanking image**, choose the appropriate value:
   + Disable: To use a plain black image for blanking.
   + Avail blanking image: To use a special image for blanking. In the **URL** field, type the path to a file in an S3 bucket. For integration with MediaLive, the bucket name mustn't use dot notation. For example, `mycompany-videos` is acceptable but `mycompany.videos` isn't. The file must be of type .bmp or .png. Also enter the user name and Systems Manager password parameter for accessing the S3 bucket. See [About the feature for creating password parameters](requirements-for-EC2.md#about-EC2Password).

# Triggers for ad avail blanking
<a name="triggers-for-ad-avail-blanking"></a>

For ad avail blanking, the ad avail mode that you set controls which SCTE 35 events result in the blanking of the content in the MediaLive outputs.

## Triggers in splice insert mode
<a name="triggers-splice-insert-mode"></a>

This section describes which message type and segmentation type combination is blanked by ad avail blanking when the Ad Avail mode is Splice Insert mode. 

[\[See the AWS documentation website for more details\]](http://docs.aws.amazon.com/medialive/latest/ug/triggers-for-ad-avail-blanking.html)

## Triggers in timesignal APOS mode
<a name="triggers-timesignal-mode"></a>

This section describes which message type/segmentation type combination is blanked by ad avail blanking when the Ad Avail mode is Timesignal with APOS mode. 

[\[See the AWS documentation website for more details\]](http://docs.aws.amazon.com/medialive/latest/ug/triggers-for-ad-avail-blanking.html)

# Ad avail blanking restriction flags
<a name="ad-avail-blanking-restriction-flags"></a>

This section provides information about the restriction flags that you can set in a MediaLive channel, when you set up for ad avail blanking.

**Restrictions in the input**

SCTE 35 messages of type time\$1signal always contain segmentation descriptors. 

SCTE 35 messages of type splice\$1insert might or might not include segmentation descriptors.

If the input has SCTE 35 messages that do include segmentation descriptors, these segmentation descriptors always include two types of flags. Each flag has a value of "true" or "false" and provides additional information as guidance for blanking in specific situations:
+ web\$1delivery\$1allowed\$1flag 
  + True means that there is no restriction on including the ad avail event’s content in a stream that is intended for web delivery: there is no need to blank out content in streams intended for web delivery. 
  + False means there is a restriction: the content should be blanked out. 
+ no\$1regional\$1blackout\$1flag

  (The wording of this flag is confusing. Think of it as the "regional\$1delivery\$1allowed\$1flag".)
  + True means that there is no restriction on including the ad avail event’s video in a stream that is intended for regional markets: there is no need to blank out content in streams intended for regional markets. 
  + False means there is a restriction: the content should be blanked out.

If neither flag is present (usually the case with splice\$1inserts), then both are considered to be false. Blanking should occur.

If both flags are present (which is usually the case with time\$1signal; it is unusual to have only one flag present), then a "false" for one flag takes precedence over a "true" for the other flag. Blanking should occur.

Typically, in any message in the input only one of these flags is ever set to false, so only one restriction is ever in place. There would typically never be *both* a regional delivery restriction and a web delivery restriction. This is because if content is considered restricted for regional delivery, then it would not also be considered restricted for web delivery (where the concept of a region makes no sense).

**Representation of these Restrictions in MediaLive**

There are two fields in MediaLive that let you control how MediaLive responds to the these flags. See [Enabling blanking](procedure-to-enable-ad-avail-blanking.md). Typically, you set the two fields to Follow (the default), to instruct MediaLive to follow the behavior implied by the value of the flag.