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Computers in Radiology |
1 All authors: Russell H. Morgan Department of Radiology, The Johns Hopkins School of Medicine, 601 N Caroline St., Rm. 3251, Baltimore, MD 21287.
Received May 17, 2007;
accepted after revision January 10, 2008.
Since this article was first written, Apple Inc. has released the iLife
software suite, which includes iTunes, GarageBand, and iMovie; also, Final Cut
Express, a less expensive version of Final Cut, is now available.
Abstract
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CONCLUSION. These image-viewing characteristics and the ease of widespread delivery are well suited for radiologic education. This article presents detailed information about how to generate and distribute a video podcast using a Macintosh platform.
Keywords: computers • iMovie • multimedia presentations • podcasting • Web-based education programs • video presentations
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Recently, other powerful handheld devices designed to download and play audio and movie media specifically, such as MP3 (Moving Picture Experts Group [MPEG], audio layer 3) players with video capability and handheld movie players, have flooded the market and become mainstream [7]. Published studies indicate that, as of early 2005, 1 in 10 Americans older than 18 years (22 million) owned an MP3 player [8] and, as of November 2006, 12% of Internet users had downloaded a podcast, including video podcasts [9]. With all of the choices of handheld media players available on the market, ease of use, and "plug and synchronize" or straightforward download and upload functions, the channels are in place to distribute video content to virtually any subscriber. Such dissemination of multimedia educational programs is well suited for an image-dependent field such as radiology.
Video "podcasting" is an Internet-based publication and syndication technology defined as the process of capturing, editing, distributing, and downloading audio, video, and general multimedia productions. Previously, podcasts only allowed the distribution of audio files, which limited lectures to topics that did not require image display. However, new technology expanding on this concept allows one to publish, disseminate, and download video files as a video podcast [9]. Like audio podcasting technology [10], video podcasting is a form of really simple syndication (RSS) feed. Video podcasts are syndication feeds that are in movie file format (MPEG-4 [Moving Picture Experts Group, audio layer 4]) instead of MP3 format (audio only). These digital presentations are not limited to video, but can use still-image slide shows, moving medical images, or animation—all common and effective media tools for displaying radiologic educational material. We have identified in the published medical literature generalized descriptions about how to create a video podcast [11, 12]. This article describes in detail how radiologists interested in creating and disseminating educational radiologic materials can produce a video podcast.
Basics of Creating a Video Podcast
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The content and style of your production will dictate which software packages you need to use. Although there are numerous ways to create a video podcast, we describe the procedure on a Macintosh (Apple Inc.) platform in this article because we use Apple's recommended techniques and software to create video podcast productions, with a few purchased software additions for increased flexibility, function, and quality [13, 14].
For Microsoft users, Windows Sound Recorder (Microsoft), which is part of the Windows operating system (OS), can be used if you have a sound card or an alternative package such as QuickTime 7 Pro (Apple Inc.) may need to be purchased as an inexpensive solution to record sound files on a PC. QuickTime 7 Pro is available for Macintosh and Windows-based computers. The following are the minimum requirements to create and distribute a video podcast.
Macintosh
Windows
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Other Windows-based audio- and video-capturing software and editing software may have a slightly different interface and functionality, but most follow timeline-based editing procedures and concepts similar to those we describe. Lectures consisting of continuous video footage of the lecturer can be created with an inexpensive digital video camera (VHS cameras can also be used) and video editing software such as iMovie for Macintosh PCs or Movie Maker for Windows PCs. iMovie and Movie Maker are included with the most recent operating systems at no extra cost.
For higher-quality video productions, professional video editing software, such as Final Cut Pro or Avid Xpress (Avid), is available for purchase. Although both of these software packages can be useful for editing professional-quality video productions, there is a steep learning curve and a large time commitment is involved in learning to use these expensive software packages.
Other styles of video podcast productions can range from simple slide shows with audio to full-length educational video productions that use combinations of video, slides, illustrations, animations, audio lecture, and music. All of this media can be imported, handled, and edited in iMovie. For increased multimedia production capabilities—such as multilayered video production, animation, still-image composition and compositing, and complex audio compilation—software such as After Effects can be purchased and used. Producers can also explore other options, such as downloading and experimenting with third-party extensions that allow users to export Power-Point (Microsoft) presentations as MPEG-4 movie file format.
When creating a podcast, it is helpful to remember one simple concept: High-quality educational material does not need to be complex. The basic requirements to create a video podcast are as follows: the ability to record or import sound onto your computer; the ability to upload and edit video footage, animation, and still images on your computer; and the ability to combine the image and audio files, edit them, and create an MPEG-4 file for video podcasts. MPEG-4 and MP3 are the only file types accepted for podcast presentation. MPEG-4 is the standard used primarily to compress audio and visual digital data. MP3 (MPEG-1 audio layer 3) is an audio-specific format compression format.
Capturing and Importing Video
The first component of video podcast creation that we discuss involves
capturing and editing video footage for a video podcast publication. For this
demonstration, we reference all functions and tools from iMovie 5.0.1. The
first step is to shoot the video using a digital video camera; a VHS video
camera can be used as well, but camera connection protocol and uploading of
video footage change. The best scenario for shooting a lecture is a well-lit
environment with a solid-colored background that provides contrast with the
focal point (i.e., the speaker, procedure, or other object of interest).
If you are recording a lecture in a large room, a close microphone setup may be desirable. To set up a close microphone, place a microphone in front of the speaker (3–5 inches [8–13 cm] is ideal and depends on the type and quality of the microphone) or attach a small lapel-style microphone to the speaker and run the line into the external microphone port on the camera, digital preamp converter (USB [universal serial bus] or FireWire [Apple Inc.]), or computer sound card; all of the details for capturing audio have been reported previously [10]. Separate video and audio files (audio recorded from a separate microphone) can be synchronized later during the editing process.
After the footage is captured on the camera, proceed to download the video footage onto your computer via a FireWire or USB connection with the camera. Video footage uploaded from a camera using USB 2.0 or FireWire is of better quality than footage uploaded using USB 1.0. After the footage is loaded and viewable in a video editing software package, such as iMovie or Movie Maker, make the edits, cuts, and transitions needed to finalize the production and render the movie file; these details and functions will be discussed later.
All of the basic camera setup, connections, and basic video editing functions are independent to specific cameras and software. Users will need to consult the product manuals for details. Most editing software packages offer a quick (30-minute) tutorial that will take you through the basic process of downloading, editing, and rendering. There are many types of digital video cameras commercially available, ranging in cost from just over $200 to $1,000, and most include USB or FireWire capabilities.
Recording Audio
Many podcast productions may require a voice-over, a separate microphone
positioned near the speaker, or additional separate audio tracks. We use
GarageBand (Windows Sound Recorder or QuickTime 7 Pro can be used on a
Windows-based PC) for recording these independent audio tracks that were not
captured with the live camera footage. GarageBand does not currently run on
Microsoft Windows computers. Windows users will need to use Windows Sound
Recorder, which is included on Microsoft PCs with a sound card; download
QuickTime 7 Pro; or download a free audio recording and editing package such
as Audacity 1.2.6 (Audacity) to record the audio portion of their production.
There are many software packages available for Windows-based PC users
developed by Steinberg, Avid, or Sony
[10]. Another place to look
for inexpensive or free quality audio editing software packages is
www.shareware.com
[7].
Although audio can also be recorded directly into many video editing programs, most programs are not specifically designed to record and edit audio files. We recommend recording any separate audio tracks in a program such as GarageBand and then synchronizing the audio file with images and other media during the image editing process. A step-by-step tutorial of the audio recording and editing process has been previously described [10].
Compiling Video, Images, and Audio
The next step is importing separately recorded audio into image and video
editing software. All of this can be done in iMovie or Movie Maker, although
at times we use a more sophisticated program called After Effects. For
demonstration purposes in this article, we use only iMovie.
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Next, import all of the images, animation, and video that will be used in the production. Click on the Clips button in the iMovie toolbox. Users can drag and drop the files from the computer's finder or they can select Import, which is located under the File menu at the top of the screen (Fig. 2). After all of the visual media have been imported into the Clips menu, drag and drop the individual images and footage files onto the timeline located at the bottom of the screen (Fig. 2). Drop these files into the timeline in the order you want them to appear in the production. Users can change the order of the footage by dragging the footage around to reorder it and can also change the duration of the still images by double clicking on the image in the timeline. A dialogue box will appear to allow the user to increase or decrease the time the image will stay on the screen.
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Editing moving media such as video, QuickTime movies, and animations is a basic function in iMovie. To cut the video footage at any point, mark the splice point with the cursor and select Split video clip at play head, which is located under the Edit menu at the top of the screen. You can perform this same function on audio files in iMovie too. Another way to cut portions of video or still images is to use the slider function in the image window to mark portions of video that are to be deleted. Select the image or footage that you would like to edit and drag the Marker over the area you want to delete. The "marked" area will be highlighted in yellow. After selecting the area, click the delete button and the area will be removed.
If the user needs the audio from a combined audiovisual file (footage from a video shoot) on a separate track to allow the user to move and cut video without splitting the audio track, extract the audio from the video. This function is located in the Advanced menu in iMovie.
After all of the edits are in place, add transitions between the cuts. There are many to choose from and they are all located under the Trans menu in the iMovie toolbox. One style consideration to keep in mind, involving transitions from scene to scene, is to keep transitions simple, clean, and as seamless as possible. We use "dissolves" and "fades" and avoid large sweeping transitions such as "wipes" or "shutter" transitions.
After the project is complete and the production is ready to be rendered as the final movie, select Share located under the File menu at the top of the screen. We then select the QuickTime icon. Next, we select Export Settings to view and set our presets. After selecting Export Settings, click Share. A second box will appear and the user can make adjustments to the settings. Export the file as an MPEG-4 file and select Options to see some of the presets. We leave most of these settings at their default settings and change a few basic presets (Fig. 3). Figure 3 shows our options "setup" window for the video settings. We choose MP4 (ISMA) (for faster data rate) as the File Format. We select MPEG-4 Improved as the Video Format. We also change the image size to 320 x 240 and change the Frame Rate to 15. We leave all Audio and Streaming settings set to default. Now click Share again, and iMovie will begin rendering the movie file. It is important to note that MPEG-4 is the only type of movie file format that is supported for video podcast publications.
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A podcast can be distributed as a downloadable file, and downloading podcast files to the user's computer allows the user to play the media off-line or on a portable media player. Any content manager that can play the MPEG-4 file format and has a monitor to view an image can be used. Content managers such as iTunes and Windows Media Player (Microsoft) will play video podcast media on PCs and portable media players with video screens. Nonetheless, video podcasts are also likely to be viewed on a desktop computer or laptop because of the expense of handheld devices, their newness [7], and their small screen size.
Examples of our use of video podcasting can be found on our Website, www.ctisus.com, linked from the main page. We are currently adding at least one new video podcast each week. At the present time, our published video lectures include 3D rendering techniques, workflow and image processing, 3D CT angiography of the gastrointestinal tract, virtual gastroscopy, cardiac CT, and many case review lectures. Our available video podcasts usually last about 8–17 minutes and use a variety of content including audio lecture, word slides, still radiologic images, animated 3D radiologic images, medical illustrations and animations, and music. All of this material is free to users.
In the future, video podcast content will likely expand beyond radiology-based lectures. Based on the groundwork of Kahn et al. [15], video podcasting technology may prove valuable to deliver just-in-time learning teaching modules. Designed for Internet point-of-care learning, podcasts are focused, educational programs of short duration that integrate literature-based text and images [15, 16]. A pilot study of Web-based modules revealed that radiologists prefer such programs to range from 5 to 15 minutes, similar in length to our current collection of video podcasts [15]. In the future, we will also see specific software packages designed to create and handle video podcasts from inception to publication as well as to manage and catalogue downloaded video podcast files [7].
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