Why SWF Is Not Actually a Video Format
When Camtasia Studio introduced ExpressShow in Camtasia Studio 5, the ability to create a single file video with a built-in player helped our customers create compelling screencasts in a simple to use package. Things have changed since ExpressShow was first introduced in 2007, especially the way we create, host, and consume video on the Internet.
The Adobe Flash format known as SWF isn’t actually designed for videos at all. Rather, it’s a versatile way to create graphics that include animations or interactivity. Camtasia Studio leverages that file format to create a video player with the video baked in. With the rise of video hosting sites like YouTube and video file formats like MP4 with H.264 encoding the problems that a SWF packaged video solved became less relevant and the downsides of using the lossless compression of SWF have started to outweigh the benefits.
The Camtasia Recorder has come a long way in the past five years. The codec used to record the screen is recording a high quality, low file size source video file. Unfortunately, because the videos that are put in a SWF file are lossless, the benefits of TechSmith’s TSC2 recording codec are lost and file sizes balloon upwards. SWF isn’t able to provide both high quality and low file size.
Another concern is a limitation of the SWF format itself: it only allows roughly 16,000 frames per file. This puts a hard limit on video length that doesn’t exist with a dedicated and more modern video format like MP4.
Finally, playback of a SWF file is something of a resource hog. Viewers’ machines have to spend a lot of resources to load and play those files. The same isn’t true of dedicated video formats.
The SWF file format solved a lot of problems for video creation when the format was first introduced in Camtasia 5 in 2007. By 2012, better solutions to those problems, without the drawbacks of SWF, have been developed.