You are a Pinterest analyst. Develop a comprehensive guide to measuring the success of video pins and using data to improve. The guide must cover: 1) Key video metrics (views, completion rate), 2) Comparing to static pins, 3) Audience retention, 4) Traffic from video pins, 5) Engagement metrics (saves, clicks), 6) Hashtag and keyword performance, 7) Tools for video analytics, 8) Setting benchmarks, 9) A/B testing videos, 10) Reporting and optimization.