YouTube's Content ID system uses a reference for an asset as the basis for determining matches and claiming videos. When a reference includes content that you don't own, you need to exclude that content from consideration when determining matches. For example, a news program might include footage received from other sources. You don't want to claim videos that match the footage you don't own.

A <reference_exclusions> tag specifies one or more time intervals in a reference that YouTube should exclude when determining Content ID matches. Each <interval> tag specifies a duration to exclude:

  <reference_exclusions>
    <interval start="0:00" end="0:10"/>
    <interval start="1:00:20" end="1:00:30"/>
  

To exclude portions of a reference from consideration during matching, include the <reference_exclusions> tag in your feed and define a relationship that associates the tag with the reference to which it applies. The feed supports two ways to associate the exclusions with a reference:

• To apply the exclusions when you create a reference file, include the <reference_exclusions> element in the relationship that creates the reference. For example:

  
   <file type="video">
      <filename>foo.mp4
    
    <reference_exclusions>
      <interval start="0:00" end="0:10"/>
      <interval start="1:00:20" end="1:00:30"/>
    
    <relationship>
      <item path="/external/asset[@id='ASSET_ID_1_']"/>
      <item path="/feed/reference_exclusions[1]"/>
      <related_item path="/feed/file[1]"/>
    
      

• To apply the exclusions to an existing reference, define a relationship between the reference and the <reference_exclusions> element. For example:

  
   <reference_exclusions>
      <interval start="0:00" end="0:10"/>
    
    <relationship>
      <item path="/feed/reference_exclusions[1]"/>
      <related_item path="/external/reference[@id='REFERENCEID']"/>
    
  

To remove the exclusions, associate an empty <reference_exclusions> tag with the reference.

  <reference_exclusions/>
  <relationship>
    <item path="/feed/reference_exclusions[1]"/>
    <related_item path="/external/reference[@id='REFERENCEID']"/>
  

* Nguồn: Youtube