Back to Basics: Making Flash Play

A primer for newbies and a refresher for veterans, Back to Basics is a regular feature examining some of the basic concepts and technologies involved with delivering online video.

While we've covered Flash as part of previous Back to Basics articles, we've never really touched on the difference between the video file formats (FLV, F4V) and the interactive file formats (FLA, SWF). An email exchange last week, though, made me realize that an explanation of the types of file extensions for Flash might be helpful.

It started innocently enough: I woke up on vacation one morning to find a Facebook post from a friend, requesting help putting a long-format video interview on a website.

"What I’m working on is setting up a series of downloadable thought leaders interviews for our organization," she wrote. "The idea is to have 2-3 minute teasers on the site, then a link for the whole download. I’m thinking a Flash download would be great—but we also might want to offer the files for WindowsMedia and RealPlayer."

I responded, figuring I could help create the video file, but first asked a clarifying question regarding the difference between downloads and streams as well as the type of Flash video file needed.

"Flash is almost always delivered more like a stream than a download," I wrote, "using a technology called progressive download. So if you want to do a true download, you might want to consider another option. Just wanted to make sure I knew what you mean by downloading, as downloading normally means the user downloads a file to their machine to watch without needed to be connected during the viewing."

I also asked whether the Flash file needs to be in FLV (a stand-alone video file that's embedded into the website's Flash video player) or SWF (a self-contained Flash file that contains the Flash video and the Flash video player, usually pronounced "swiff"). I also sent a sample FLV file for testing, suggesting it could be viewed on the desktop using Real Player or Adobe Media Player (AMP).

At this point, the typical confusion about the difference between Flash, Flash Video and even the Flash Player comes in to full force, and this time was no exception.

"I tried to open the file in Flash [Professional] CS3," she wrote, "but it defaults to having me import it. I follow basic settings without changing a thing; it imports. but I can't see it... What am I not doing right?"

Most consumers of video files are familiar with the fact that video files correspond to their complementary video player: QuickTime (MOV) files can be played in QuickTime Player; Real (RM, RMA, RMV) in Real Player; Windows Media in the Windows Media Player (or on the Mac with QuickTime Player and Telestream's Flip4Mac).

For those who encounter Flash Video files, though, the ability to play that content on the desktop has been somewhat maddening; even after the advent of AMP, it still takes some thought to make sure content plays correctly on the desktop, since SWF files default to Flash Professional and FLV files default to AMP.

The thing most users don't understand is the difference between Flash and Flash Video. Flash is the interactive part of the process, which allows the creation of the player that is designed to interactively manipulate the video: stop, fast-forward, rewind, etc.

Flash Video on the other hand, is just the video file that the Flash SWF file plays, using the Flash Player. SWF files may include video content that has been imported from FLV or F4V files, or may merely reference external FLV/F4V video files which the SWF file will play back at certain pre-defined or user-input intervals.

Confused? Let's look at it this way.

Video files come in two flavors: FLV or F4V, which can be thought of, at a basic level, as standalone video files for Flash Players version 6-10, with Sorenson Spark and On2's VP6 being the two primary codecs designated with the FLV extension and H.264 designated with the F4V extension.

FLV
FLV files can play on any of the Flash Player versions noted above, while F4V files can only be played with Flash Players 9 (v3) and 10. All of these files can also be played on Adobe Media Player, which itself runs on the Adobe Integrated Runtime (AIR) platform.

SWF
SWF files are the output of programming interactivity using Flash Professional. SWF files can be played back using Flash Player, and SWF files primarily play through the Flash Player web browser plug-in.