BACKGROUND

Sentinel sequences may identify transitions between a first type of content and a second type of content. These sequences may also be referred to as “bumper” sequences. Sentinel sequences may be short clips or animations that typically last a short period of time, such as 2-5 seconds, and can be replayed several times in the same video. Also, similar sentinel sequences may be displayed in other videos over a time period, such as over the course of a day or longer.

The sentinel sequences may be identified using one or more key frames that are manually extracted from the recorded content. For example, a user may manually view the content and identify the sentinel sequences. Then, the user needs to manually extract a frame from the sentinel sequence. This may help an ad detection system to replace the ads. However, this is a highly manual process, and it is hard to train a user to extract the correct sentinel frame.

