Interpret prediction results from video classification models

After requesting a prediction, Vertex AI returns results based on your model's objective. Predictions from a classification model return shots and segments in your videos that have been classified according to your own defined labels. Each prediction is assigned a confidence score.

The confidence score communicates how strongly your model associates each class or label with a test item. The higher the number, the higher the model's confidence that the label should be applied to that item. You decide how high the confidence score must be for you to accept the model's results.

Score threshold slider

In the Google Cloud console, Vertex AI provides a slider that's used to adjust the confidence threshold for all classes or labels, or an individual class or label. The slider is available on a model's detail page in the Evaluate tab. The confidence threshold is the confidence level that the model must have for it to assign a class or label to a test item. As you adjust the threshold, you can see how your model's precision and recall changes. Higher thresholds typically increase precision and lower recall.

Example batch prediction output

The following sample is the predicted result for a model that identifies cats and dogs in a video. The result includes segment, shot, and one-second interval classifications.

{
  "instance": {
   "content": "gs://bucket/video.mp4",
    "mimeType": "video/mp4",
    "timeSegmentStart": "1s",
    "timeSegmentEnd": "5s"
  }
  "prediction": [{
    "id": "1",
    "displayName": "cat",
    "type": "segment-classification",
    "timeSegmentStart": "1s",
    "timeSegmentEnd": "5s",
    "confidence": 0.7
  }, {
    "id": "1",
    "displayName": "cat",
    "type": "shot-classification",
    "timeSegmentStart": "1s",
    "timeSegmentEnd": "4s",
    "confidence": 0.9
  }, {
    "id": "2",
    "displayName": "dog",
    "type": "shot-classification",
    "timeSegmentStart": "4s",
    "timeSegmentEnd": "5s",
    "confidence": 0.6
  }, {
    "id": "1",
    "displayName": "cat",
    "type": "one-sec-interval-classification",
    "timeSegmentStart": "1s",
    "timeSegmentEnd": "1s",
    "confidence": 0.95
  }, {
    "id": "1",
    "displayName": "cat",
    "type": "one-sec-interval-classification",
    "timeSegmentStart": "2s",
    "timeSegmentEnd": "2s",
    "confidence": 0.9
  }, {
    "id": "1",
    "displayName": "cat",
    "type": "one-sec-interval-classification",
    "timeSegmentStart": "3s",
    "timeSegmentEnd": "3s",
    "confidence": 0.85
  }, {
    "id": "2",
    "displayName": "dog",
    "type": "one-sec-interval-classification",
    "timeSegmentStart": "4s",
    "timeSegmentEnd": "4s",
    "confidence": 0.6
  }]
}

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