Poster frame generation pricing

MediaConvert allows to generate a Poster frame by adding another output group as described in https://aws.amazon.com/blogs/media/create-a-poster-frame-and-thumbnail-images-for-videos-using-aws-elemental-mediaconvert/. I couldn't find any information about poster frame pricing. Technically it's another output, however charging the same amount as for video output sounds a bit too expensive?