Content-modification system with unscheduling feature

A content-presentation device comprising:

• a content-presentation element configured for presenting content received by the content-presentation device;
• one or more processors;
• and
• a non-transitory computer-readable storage medium having stored thereon program instructions that, upon execution by the one or processors, cause the content-presentation device to carry out operations including:
• while receiving content for presentation on the content-presentation element, determining an upcoming first temporal interval and an immediately following second temporal interval during both of which the presentation of the received content is modifiable;
• transmitting a first request for first supplemental content;
• transmitting a second request for second supplemental content;
• receiving a link that points to a set of content items arranged in a playlist, wherein when the first request is transmitted, the playlist includes the requested first supplemental content, and at subsequent time after the first request is transmitted the playlist is modified to also include the requested second supplemental content positioned immediately after the first supplemental content;
• using the received link to retrieve the first supplemental content;
• using the retrieved first supplemental content in a first content-modification operation to modify presentation during the first temporal interval of the received content;
• prior to completion of the first content-modification operation:
• (i) using the received link to start retrieving the second supplemental content for upcoming use in a second content-modification operation scheduled immediately following the first content-modification operation in order to modify presentation during the second temporal interval of the received content, and (ii) making a determination that while less than a threshold portion of the first content-modification operation remains to be completed, retrieving the second supplemental content has not yet completed;
• and
• responsive to the determination, unscheduling the second content-modification operation, wherein unscheduling the second content-modification operation comprises:
• prior to the start of the second temporal interval, canceling modification of the received content with the second supplemental content that had been scheduled for the second temporal interval.

A non-transitory computer-readable storage medium having stored thereon program instructions that, upon execution by one or more processors of a content-presentation device, cause the content-presentation device to carry out operations including:

• while receiving content for presentation determining an upcoming first temporal interval and an immediately following second temporal interval during both of which the presentation of the received content is modifiable;
• transmitting a first request for first supplemental content;
• transmitting a second request for second supplemental content;
• receiving a link that points to a set of content items arranged in a playlist, wherein when the first request is transmitted, the playlist includes the requested first supplemental content, and at subsequent time after the first request is transmitted the playlist is modified to also include the requested second supplemental content positioned immediately after the first supplemental content;
• using the received link to retrieve the first supplemental content;
• using the retrieved first supplemental content in a first content-modification operation to modify presentation during the first temporal interval of the received content;
• prior to completion of the first content-modification operation:
• (i) using the received link to start retrieving the second supplemental content for upcoming use in a second content-modification operation scheduled immediately following the first content-modification operation in order to modify presentation during the second temporal interval of the received content, and (ii) making a determination that while less than a threshold portion of the first content-modification operation remains to be completed, retrieving the second supplemental content has not yet completed;
• and
• responsive to the determination, unscheduling the second content-modification operation wherein unscheduling the second content-modification operation comprises:
• prior to the start of the second temporal interval, canceling modification of the received content with the second supplemental content that had been scheduled for the second temporal interval.