Trying to find the right settings for video compression can be a tricky thing when it comes to streaming media. You want the video to look as clean and clear as possible without losing any quality, but you also don’t want super large files that take forever to load over internet connections. Where is the happy medium? It all depends on your project and what sort of files you are compressing to. In this blog we are going to be discussing using Flash Video Files (FLV) within Articulate Storyline.
We used FLV files for our project because we shot our subject on a green screen. The green screen allowed us to key him out and onto any background that we wanted and create an alpha channel on the video. The alpha channel is really a mask– it specifies how the pixel’s colors should be merged with another pixel when the two are overlaid, one on top of the other. Storyline accepts .mov files with alpha channels, but it converts the .mov file to an MP4 file and gets rid of the alpha channel, rendering your file useless. If you are not using an alpha channel on your video, compressing to MP4 files works great.
Scott Downey, Associate Professor of Agricultural Economics at Purdue University, shot in front of green screen for an eLearning presentation.
Since we shot our subject in 1080p HD (1902×1080 pixels) and our module slide size was 756×571, we decided to resize the video in After Effects (where we created the alpha channel) to fit the new dimensions of the Storyline slide. We then had to convert and compress the footage to an FLV file. This is where you want to make sure that the quality of your compressed footage meets that happy medium. We found that compressing the footage to 1200kbps kept the quality looking great and kept the file size down quite a bit. We could have dropped the compression rate down to 1000kbps or even 800kbps, but the audio and video would go out of sync and the quality of the video was starting to suffer.
Scott Downey from Purdue University with the green screen keyed out and edited on a new background using an alpha channel in the FLV video file.
Overall, it really does depend on your project and what sort of footage you are using. Someone standing and talking to the camera won’t have as much data information to process as footage of a basketball game or a concert. It takes more data to process footage that is changing rapidly, so you might have to tweak your settings a bit to see what works best for you.
Remember to consider your audience when creating FLV files. Apple products such as iPhones or iPads do not read FLV files, so you have to be sure that anyone who is viewing your eLearning Project is doing so on a device that is compatible. If you are using alpha channels, this is a very difficult thing to navigate around, so be careful. But, if you are just creating video files without alpha channels your best bet is converting your footage to MP4 files and publishing your files with the HTML5 option selected.