Consume metadata embedded in a Kinesis video stream

To consume the metadata in a Kinesis video stream, use an implementation of MkvTagProcessor:

public interface MkvTagProcessor {
        default void process(MkvTag mkvTag, Optional<FragmentMetadata> currentFragmentMetadata) {
            throw new NotImplementedException("Default FragmentMetadataVisitor.MkvTagProcessor");
        }
        default void clear() {
            throw new NotImplementedException("Default FragmentMetadataVisitor.MkvTagProcessor");
	    }
    }
}

This interface is found in the FragmentMetadataVisitor class in the Watch output from cameras using parser library.

The FragmentMetadataVisitor class contains an implementation of MkvTagProcessor:

public static final class BasicMkvTagProcessor implements FragmentMetadataVisitor.MkvTagProcessor {
    @Getter
    private List<MkvTag> tags = new ArrayList<>();

    @Override
    public void process(MkvTag mkvTag, Optional<FragmentMetadata> currentFragmentMetadata) {
        tags.add(mkvTag);
    }
    
    @Override
    public void clear() {
        tags.clear();
	}
}

The KinesisVideoRendererExample class contains an example of how to use a BasicMkvTagProcessor. In the following example, a BasicMkvTagProcessor is added to the MediaProcessingArguments of an application:

if (renderFragmentMetadata) {
    getMediaProcessingArguments = KinesisVideoRendererExample.GetMediaProcessingArguments.create(
        Optional.of(new FragmentMetadataVisitor.BasicMkvTagProcessor()));

The BasicMkvTagProcessor.process method is called when fragment metadata arrives. You can retrieve the accumulated metadata with GetTags. To retrieve a single metadata item, first call clear to clear the collected metadata, and then retrieve the metadata items again.