import (
"context"
"fmt"
"io"
"io/ioutil"
video "cloud.google.com/go/videointelligence/apiv1"
videopb "cloud.google.com/go/videointelligence/apiv1/videointelligencepb"
"github.com/golang/protobuf/ptypes"
)
// objectTracking analyzes a video and extracts entities with their bounding boxes.
func objectTracking(w io.Writer, filename string) error {
// filename := "../testdata/cat.mp4"
ctx := context.Background()
// Creates a client.
client, err := video.NewClient(ctx)
if err != nil {
return fmt.Errorf("video.NewClient: %w", err)
}
defer client.Close()
fileBytes, err := ioutil.ReadFile(filename)
if err != nil {
return err
}
op, err := client.AnnotateVideo(ctx, &videopb.AnnotateVideoRequest{
InputContent: fileBytes,
Features: []videopb.Feature{
videopb.Feature_OBJECT_TRACKING,
},
})
if err != nil {
return fmt.Errorf("AnnotateVideo: %w", err)
}
resp, err := op.Wait(ctx)
if err != nil {
return fmt.Errorf("Wait: %w", err)
}
// Only one video was processed, so get the first result.
result := resp.GetAnnotationResults()[0]
for _, annotation := range result.ObjectAnnotations {
fmt.Fprintf(w, "Description: %q\n", annotation.Entity.GetDescription())
if len(annotation.Entity.EntityId) > 0 {
fmt.Fprintf(w, "\tEntity ID: %q\n", annotation.Entity.GetEntityId())
}
segment := annotation.GetSegment()
start, _ := ptypes.Duration(segment.GetStartTimeOffset())
end, _ := ptypes.Duration(segment.GetEndTimeOffset())
fmt.Fprintf(w, "\tSegment: %v to %v\n", start, end)
fmt.Fprintf(w, "\tConfidence: %f\n", annotation.GetConfidence())
// Here we print only the bounding box of the first frame in this segment.
frame := annotation.GetFrames()[0]
seconds := float32(frame.GetTimeOffset().GetSeconds())
nanos := float32(frame.GetTimeOffset().GetNanos())
fmt.Fprintf(w, "\tTime offset of the first frame: %fs\n", seconds+nanos/1e9)
box := frame.GetNormalizedBoundingBox()
fmt.Fprintf(w, "\tBounding box position:\n")
fmt.Fprintf(w, "\t\tleft : %f\n", box.GetLeft())
fmt.Fprintf(w, "\t\ttop : %f\n", box.GetTop())
fmt.Fprintf(w, "\t\tright : %f\n", box.GetRight())
fmt.Fprintf(w, "\t\tbottom: %f\n", box.GetBottom())
}
return nil
}
