Analysis Task Output Tracks

The events that occur in video usually span many frames. For example, a person, object, or logo might appear on screen and remain there for several minutes. Media Server analyzes video frame by frame, but many analysis engines track events across frames because analyzing multiple frames can improve accuracy.

Analysis tasks can produce many different output tracks but, regardless of which track they belong to, records that relate to the same event always have the same ID.

TIP:

Data and DataWithSource tracks contain a lot of information, usually more than you want to output from Media Server. These tracks are intended to provide data for subsequent analysis tasks. For example, you can use the DataWithSource track from face detection as the input for face recognition, so that face recognition can analyze each face across multiple video frames.

The following diagram shows how face detection creates records (represented by rectangles) when a face appears in a video.

The following diagram shows how face detection creates records (represented by rectangles) when two faces appear in a video. All of the records related to the same detected face (the same event) have the same ID. So, in the following example, all of the blue records (1) would have the same ID and all of the green records (2) would have the same ID.

In both of the previous examples:

Some analysis tasks process the output of other engines. Face recognition, for example, processes records that are produced by face detection. You can see from the examples, above, that the face detection DataWithSource track provides much more information than the ResultWithSource track. When you configure face recognition, you can choose which track to process. Processing the DataWithSource track can result in better accuracy, because face recognition processes multiple video frames for each detected face. However, processing all of these frames is more computationally intensive and you should configure this only if your server has sufficient resources.

For information about the tracks that are produced by Media Server tasks, and the information contained in each track, refer to the Media Server Reference.


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