One of our special education teachers made the video above using WeVideo. First off I should say we flip for not just mainstreamed students, but also special ed and ESOL (ESL) students.
WeVideo is an app that you can add in Google Drive or sign up for separately. As with everything else here, it is free and pretty amazing as it lets you add in sound, video, words, effects, etc. Best of all, you can use it with your students in groups as it lets them collaborate much as one can do on a document in Google Drive.
Below is an introductory video on WeVideo and here are all their (short) tutorials