Streaming Media - August/September 2007 - (Page 50)

a crash course in flash video There are also two command-line encoders currently available that transcode video into FLV format on the server side: ffmpeg (PC) and ffmpegX (Mac). These are widely used by user-generated video sites such as YouTube to automatically convert uploaded videos to FLV. Both of these tools are open source, and free. opment to customization, which the other two options don’t do. There’s also a stripped-down version, called Red5-minimal that just provides streaming capabilities if that’s all you need. Red5 and Red5minimal can be compiled to work on virtually any operating system. Red5 could be a good solution for you if you’re a server geek (or have one on staff). The best part? It’s free. How Do I Serve Flash Video? There are two ways to serve Flash Video to your audience: by progressive download or by streaming. • Progressive Download. Progressive video is served from a standard web server. Like any other file viewed in a browser, it is cached and viewed as it downloads. You don’t need any special software or server technologies to deploy Flash Video via progressive delivery. • Streaming. Streaming delivery uses RTMP (Real Time Messaging Protocol), rather than the standard HTTP, to send over the video file. This sounds complicated, but it’s really just a different way of sending data to the browser. It’s real time, as the name states, which means that the video data is displayed as it is received, rather than cached. So, Should I Use Streaming or Progressive Download? The answer depends on several factors: • How long are your videos? Progressive download is best for short videos, generally five minutes or less. Streaming video is most efficient for delivery of longer videos such as seminars, feature-length films, or shorts. • Do you need to allow your viewer to navigate smoothly through the video? Progressive download has some limitations when it comes to navigation. You can only seek forward in a video if the point you’re seeking has been downloaded into your browser cache. This means that you can’t jump to the middle of a video as soon as it loads; you have to wait until that video data is downloaded first. Streaming video, however, doesn’t have this restriction. Since you’re displaying the video data as it’s received, you can jump around as much as you like, and you’ll There are currently three choices for deploying streaming Flash Video: Figure 5. Detail of the Flash Properties window. • Adobe’s Flash Media Server • Wowza Media Server • Red5 The obvious first choice is Adobe’s Flash Media Server (FMS). FMS runs on Windows or Linux servers, and provides video and audio streaming, and two-way data sharing capabilities. With FMS and Flash, you can create applications such as live videoconferences, text chat, or pre-recorded video feeds. There’s even an edge-origin server available to handle large-scale, high-traffic video streaming. The Wowza Media Server is a commercial competitor to FMS. It has fewer bells and whistles, but also allows for live or pre-recorded audio, video, and data streaming. It’s more affordable than FMS, and is gaining ground with companies who are getting into streaming but may not have a need for all of FMS’s features and want to save a buck or two. It also runs on Windows and Linux, as well as additional platforms such as Mac OS X. Red5 is an open-source solution for streaming Flash Video. It’s also a whole lot more. It streams FLVs, yes, but it also opens up the server-side devel50 STREAMING MEDIA August/September 2007 start receiving the video data right at the point you’ve chosen. Another navigation issue to note is the smoothness of the playback when seeking. Progressively downloaded video can only seek to keyframes. Therefore, if you choose a spot that’s between keyframes, the video will snap forward or backward to a keyframe, resulting in a “stuttering” navigation. This can be a bit frustrating to viewers who are trying to jump to a specific point in a video. Streaming video doesn’t have this issue at all, as keyframes are generated on-the-fly by the streaming server, as needed. • Is the video content copyright-sensitive? When serving video via progressive download, the FLV data is actually cached and stored on the viewer’s hard drive. The file is not easily located, but any somewhat tech-savvy teen could figure out where it is, grab the FLV, and share it to his heart’s content. This can be a real problem for content creators who are concerned about where their videos end up. In streaming delivery, the data is displayed as it’s received then flushed from memory, so it’s never cached or saved. • Are you concerned with bandwidth consumption and server load? If you’re watching your bandwidth calories carefully, you may want to choose streaming. Unlike progressive download, streaming only delivers the data that’s displayed. If the

Table of Contents Feed for the Digital Edition of Streaming Media - August/September 2007

Table of Contents Sweet Sixteen Letters to the Editor Technology and Business Trends IBM Takes Webcasting to the Desktop ROI in the EDU Bank Serves Espresso, Enterprise Video Online Video Advertising: Hit or Miss MLB’s Foul Bawl A Crash Course in Flash Video Newspapers in Multimedia Metamorphosis Webcasting Large Entertainment Events: Seeing Through the Hype Webcasting With Windows Media Can’t Start A Fire . . . A WiMAX Primer Mobile Video at Last Telestream Episode Pro Grass Valley ProCoder 3 Silverlight Is No Flash Killer

Streaming Media - August/September 2007

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