AV Foundation makes it reasonably straightforward to capture video from the camera and edit together a nice family video. This session is not about that stuff. This session is about the nooks and crannies where AV Foundation exposes what's behind the curtain. Instead of letting AVPlayer read our video files, we can grab the samples ourselves and mess with them. AVCaptureVideoPreviewLayer, meet the CGAffineTransform. And instead of dutifully passing our captured video frames to the preview layer and an output file, how about if we instead run them through a series of Core Image filters? Record your own screen? Oh yeah, we can AVAssetWriter that. With a few pointers, a little experimentation, and a healthy disregard for safe coding practices, Core Media and Core Video let you get away with some neat stuff.