Among the more exciting evolutionary changes brought about by the digital era is the opportunity for students and teachers to create and share lively classroom presentations. In fact, as educators become increasingly aware of the power of multiple approaches to instruction, the effectiveness of activities, lessons, and presentations incorporating video and other media elements is achieving widespread acceptance in classrooms both nationwide and globally. Research shows that when students can see, hear, and participate interactively in their own learning, they're motivated to spend more time on task. They also retain what they've learned in more depth and for a much greater period of time than with traditional exercises. Thus, partial or entire video-based classroom projects, which offer kids practice in collaborative research, writing, editing, designing, and other "real life" skills are finding their way more and more into all areas and levels of the curriculum.
If your PhD. is in distance learning technologies, what follows isn't really for you. Instead, we're presenting an overview of delivery technologies for those who have yet to take their first steps in using digital media in the classroom.
Adding new media pizzazz to traditional assignments can be accomplished in a variety of ways depending upon the technology resources available. On the video spectrum, students might begin by creating visual backdrops to accompany their oral presentations These presentation can then be shown on classroom projectors or televisions. History, literature, and even math lessons can be spiced up by infusing video or still images, either as core content or as an instructive visual backdrop.
As student and teacher technology skills improve, however, entirely video-based projects offer some definite advantages, such as the ability to store and archive them in a library of lessons to be used in the future. Completed video projects can be shown directly from the computer, videotaped or recorded onto DVDs for easy transport and long-term storage.
Student video projects can also add a new dimension to the school Web site. In addition to teacher areas that might display assignments, calendar items, or password-protected access to individual student test scores and class averages, student areas can showcase e-portfolios, or authentic work. Archived projects, for example, can allow parents to actually experience firsthand the presentations their children make in school-and from this gain a real perspective of their progress over the course of a school year.
For a range of projects that will help you get started with digital video in your classroom or school, see "Pathways to the Future," in this issue.
Whether you are integrating simple animations into your presentations or building full blown video projects, there is no end to the software available to students. For animations, Macromedia Flash is probably the most widely known software product. Flash is a descendant of Macromedia Director, an interactive CD-ROM authoring product, and shares a similar workflow for creating animations. Many Flash animations find themselves on the Internet as games or opening animations, but the software can be used to create standalone animations. Animations can be extended to include interactivity with Flash's scripting language. Thought of simply, Flash animation can be Web sites unto themselves with different images or data being presented depending upon where students click their mice.
For video projects, the number of software tools and their myriad uses can be overwhelming. For editing, software like Apple iMovie can be a great start for labs equipped with Macintosh computers. For Windows users, products like Pinnacle Studio ($99), Ulead Videostudio ($99.95), or Roxio Videowave ($49.95) are available for editing your video content. All provide video capture and entry level editing features (for more on video editing, see "DV Editing," in this issue).
Once your students have created and edited their video projects, there are a number of options for getting their work seen available to them. They can output it to videotape, turn it into a Web-friendly file, or burn it onto a DVD. However, while video files can be directly written to DVDs in a manner similar to putting audio on CDs, creating something that can be played back on a home DVD player takes a little more work (for details on consumer DVD players, recordable media, and recordable format compatibility issues, see Ralph LaBarge's cover story in DV, July 2002). Windows users have a variety of DVD authoring tools to choose from, including Pinnacle Instant CD/DVD ($99.99), Sonic Solutions myDVD ($79.99), Ulead DVD Workshop ($299), and Adobe Encore ($549 street), as well as NLEs such as Avid Xpress Pro ($1,695), and Sonic Foundry Vegas+DVD ($799) that can export directly to DVD. Mac users have Apple's free iDVD for simple projects and DVD Studio Pro ($499) for more complex professional creations. (Note: all prices are MSRPs, educational discounts are available for most of these products. Consult individual vendors for details.)
Projects can quickly grow to several hundred megabytes, which can be not only difficult to move from computer to computer, but can also impede realtime playback. Projects can be shrunk via file or data compression. File compression involves compressing the file as a whole to take up less space on the disk. Such files are saved as either a SIT, ZIP, TAR, or GZ file to the disk. While this type of compression can free up more space on your hard drive, the file will need to be uncompressed before playback. Compressing files in this manner does nothing to increase the playback speed, though such compression leaves the quality of the original file untouched. Note however that shrinking a video file with a compression app such as PKZIP or StuffIt has been known to corrupt video files.
To improve the playback speeds of your files, the data within the file will need to be compressed. This can be done with a variety of software products including Real Producer, Windows Media Encoder, Sorenson Squeeze ($499), Discreet Cleaner ($599), and Canopus ProCoder ($699). Cleaner and ProCoder offer options for optimizing the video signal for the intented playback format, while Real Producer and the Windows Media Encoder are specific to their own proprietary codecs (explained below). Most modern NLE software also includes built-in video compression utilities for outputting popular formats suitable for streaming or playback from computer or DVD such as Real Video, Windows Media Video, QuickTime, MPEG-2, and MPEG-4.
The video data is compressed with an algorithm referred to as a codec (COmpressor/DECompressor). There are many codecs available designed to compress video and allow for playback online over the Internet or an intranet, on disk (CD or DVD), and on-air (as in broadcast or satellite delivery). Some codecs sacrifice quality for file size, while others try to achieve a good balance between quality and size. The most popular for video are MPEG-4, Windows Media, Sorenson, and Real Video. QuickTime is often lumped into the codec category, but it's not a codec. QuickTime is best thought of as a codec container in that it supports a wide variety of codecs, including in QuickTime 6, MPEG-4.
Using a codec to compress video data creates a smaller file to fit on your hard drive along with providing a file that will do a better job of playing back in realtime. Possible drawbacks to using a codec include inferior quality. Most codecs allow the quality/file size ratios to be adjusted to your specific liking. This requires a bit of trial and error to find the exact settings that provide quality that you deem acceptable and still reduce the overall file size. Another tradeoff, however, is often encoding speed. Achieving higher quality at lower file sizes or bitrates, requires more computations, and more computation equates with longer rendering times, though with today's CPUs running at a few gigaHertz, rendering times are getting shorter and shorter.
Streaming down the network
Video can be streamed, or transmitted over a local school network or the Internet, to students and faculty for viewing. There are three popular streaming video formats are Apple QuickTime, Microsoft Windows Media, and Real Video from Real Networks. Each has their respective proponents and often, the streaming type chosen depends upon the computer hardware utilized by each particular school. For example, a school whose computers are primarily Apple Macintoshes, Windows-based PCs, or Solaris-based servers would likely choose QuickTime, Windows Media, and Real respectively, for reasons having to do with availability (QuickTime is Apple's technology; the Windows Media Encoder only runs under Windows; Real's technology is available on the widest variety of platforms and operating systems).
Streamed video can encompass everything from school announcements, internal television broadcasts of theatrical performances, sporting events, and class lectures.
Video that's already been captured and edited on the computer can be streamed directly from the server, or video can be captured and streamed on the fly. For live presentations, video is captured and encoded by products designed to work specifically for a given server: Apple QuickTime Broadcaster, Microsoft Windows Media Encoder, or RealProducer.
The possibilities are almost endless for ways students can add creativity to their class projects. From animations to video, every student should find a way to bring life to everything they create and thereby involve them deeper in the learning process.
Darrin Woods has 15 years experience in carrier and enterprise class systems & network engineering specializing in video transmission, he worked in and taught 3D graphics and animation, and teaches distance learning at the Digital Media Academy. Reach him at email@example.com.
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Hardware or Software: Wading the video stream
Shrinking the Video: how codecs work
Codec (COmpressor/DECcompressor). Technology for compressing and playing back a file.
Decoder. Software or hardware that utilizes a codec to decompress video/audio files.
DVD (digital video/versatile disc). Similar to data or music CDs, but able to hold much more data. DVDs can have up to two layers per side. Up to 4.7 GB can be stored on each layer, providing about 18 GB of storage on a double-sided, double-layered disc. Consumer-grade DVD burners will only write to single-layer, single-sided discs.
DVD-ROM (DVD-Read Only Memory). Format for creating read-only DVDs containing data intended to be read from a computer.
DVD-R or DVD+R (DVD Recordable). Currently single-sided, single-layered DVD that can have data or video written to it once. -R and +R are two competing formats with -R being the most prevalent. Recordable DVDs may be played back from most consumer DVD players or computers equipped with a DVD drive.
DVD-RW or DVD+RW (DVD ReWritable). Currently single-sided, single-layered DVD that can be written to, erased, and used again. -RW and +RW are competing formats with -RW being the most prevalent. DVD Rewritable discs can be played back from some consumer DVD players or computers equipped with a DVD drive.
Encoder. Software or hardware that utilizes a codec to compress video/audio files.
MPEG (Motion Picture Experts Group). Standardized format for storing and transmitting video data. Currently there are three video MPEG standards: MPEG-1, MPEG-2, and MPEG-4. MPEG-1 was used initially for consumer satellite television, but is hardly used anymore. MPEG-2 is currently the most common and used for consumer DVD movies and newer consumer satellite television services. MPEG-4 is currently used for Internet streaming of video, but may possibly replace MPEG-2 as the format of choice in consumer DVD players and satellite television in coming years.
NLE (NonLinear Editor). Until computer-based editing was available, video used to be edited in a linear fashion. Meaning that the video was created from the beginning scene to the ending scene, in chronological order. NLEs enable an editor to work on any part of the video at any time.
Read other articles from the July Issue