Andrew Montgomery from Roycemore School presented how he manages a flipped classroom. I think the one thing we should take away from his presentation is that he does not expect the videos and resources that he posts to replace classroom instruction. They are posted to allow students to preview the material before class and to review the material after class. He realizes that (a) some kids do not have Internet access at home, and (b) some kids simply won't watch the videos even if they are considered a requirement. Posting the videos helps students get ahead or to at least keep up with the class.
His videos are 5 - 9 minutes long which helps to keep them interesting and focused. His videos are all narrated whiteboarding sessions using his Mobi board to write and Screencast-O-Matic to do the recordings, or they are narrated presentations/ PowerPoints.
Along with the videos, he also posts additional materials and links to go with the lessons. He uses Khan Academy, a site with high-quality video lessons that focus mainly on math and science but the site does include other subjects and topics.
The overall focus for Mr. Montgomery is to use the videos to help students prepare for the lesson that day. Students have a rough idea before class begins whether or not they understand the material, and they are prepared to ask focused questions during the instruction. They are ready for the lesson, which makes the instructional piece go faster and therefore allows for more time to practice the material, i.e. do their homework in class while the teacher is still with them and available to answer their questions.