Creating video for an on-line, multilingual database
Project Background
The video instructions and examples linked here were developed as part of the Global Performing Arts Database (GloPAD, see www.glopad.org), an online, multilingual database project for materials and information on performing arts worldwide. Because the GloPAD project works with contributors and user-viewers from around the world, a video system needed to be decentralized, accommodating various computer systems for both the video authors and the video viewers. The key features we demanded from a system were to rely on open-source, freeware, or low-cost programs, to be able to create and attach subtitles or other timed text annotations in multiple languages, and to be easily uploaded to and distributed by the browser-based database system so that Internet users could view the products using common computer equipment and media players. We also wanted to be able to make products that could reside in the database in such a way that their component parts could be extracted and used for other purposes in the future. For example, this meant that we did not want subtitled videos where the subtitle text is an integral ("burned in") part of the video package.
As part of developing a system for our contributors to use we wrote up several sets of instructions on creating videos and subtitled videos for use on the GloPAD system. We have abstracted from those instructions some of the procedures we think are generally useful beyond our specific project.
Tutorials offered here
Linked to this Web page are three sets of instructions for authoring video for online distribution. Two of these tutorials show how to create timed text subtitles in multiple language scripts, while the third describes how to put together a hosting Web page for convenient viewing. Each tutorial includes template files that can be used or modified to suit one's own needs.
The instructions here work with Quicktime video, which for reasons of resources, adaptability, and viewing we found to be
the most useful for our project at the time. However, we are also currently working on setting up the same authoring, timed text creation, and distribution procedures using Flash video (the .flv format).
The Flash version
We are developing a Flash instance of the video system because Flash has the greatest browser plug in saturation of any of the online video formats and media players, and because the video, or mixed media, files of Flash are relatively small and therefore take less bandwidth to distribute.
For the Flash part of the system we are setting up a server-side transcoding and file-handling program that will automatically derive .flv video files and insert them into a hosting template page. At the moment the Flash system works by using a freeware program, ffmpegX for Macintosh, to transcode a contributor's video file to the Flash video format (.flv) and then someone manually filling out the file names and text parameters in a PHP file template to make a hosting Web page. The resuIting Web page, with its attached image and video files, is then uploaded to the database using the same CMO upload procedure as used for the Quicktime version of the hosting page. In fact, the basic difference between this Flash version and the Quicktime version is that the Flash video replaces the fast-forward preview clip of the Quicktime version (see Viewing and Previewing below). In the near future we will be incorporating the transcoding software (ffmpeg) and the PHP template into the database upload system so that a contributor will simply upload their original video file--in one of several basic video file formats--and fill out a few text fields and the system will automatically create the Flash video and still thumbnail images and insert all these into the host page template for distribution through the GloPAD public interface. Because we are automating the authoring process to such a degree we are not including instructions on putting together the Flash version of the hosting page, however see below for a screen shot of the Flash GloPAD Video Viewer page.
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Subtitling in multiple scripts
The major obstacle faced by the development of our system was to be able to create timed text subtitles in various language scripts and to get these to play online in common media players. The problems of fonts, encodings, and the lack of internationalization of software programs set up many hurdles to creating a coherent system of use for our editor contributors. We did not want to inscribe the subtitle text into the video because we wanted to allow the future use of the uploaded video and audio, without the timed text. There are any number of captioning software programs that will create separate text tracks, but we found that most will not work with font sets and encodings outside the operating systems for which they were designed. Other transcriptions programs, such as the linguistics-based Quilldriver, were very good at timing texts and handling various language scripts, but required the end users to download and use special software to view the text-annotated video. We felt that we could not demand such extra work from our database viewers. The current instructions show how to make Quicktime text tracks using simple captioning procedures and how to make them play successfully within the Quicktime player. Magpie, a captioning tool developed by The National Center for Accessible Media (NCAM), is a wonderful, freely-available program that works with the standard video formats, but that does not handle certain language scripts. We have adapted some procedures to generate text tracks in extended character set language scripts so that one can use this program to cue one's text to the video and then use a simple text editor to substitute the script of your choice in a file that can be imported by the QuicktimePro video editor. Many thanks to the people at NCAM for working with us to iron out the tricky details of making this system work.
For the Flash version of the video viewer we are working on means to time text directly to the Flash video playing within the hosting page. The main obstacle for this is that there is no appropriate captioning tool that will work with Flash and the extended font sets that we require to make text tracks in languages such as Japanese, Russian, and Chinese. In principle the matter is simple: have a region on the host page for text to display and use XML or SMIL to tell the server to display lines of text from a simple text file at certain timed durations. We have already incorporated multiple subtitle regions into the Flash hosting page, directly below the video player. The issue is making the authoring of the cued text simple for editors, experts who know the contents of the video well enough to translate them into running text commentary, but experts in the performing arts content of the video rather than in file systems, mark up languages, and digital video editing. We currently have plans to create a simple authoring tool for this purpose. Contributing editors will then upload, along with their video, a text file of their subtitle text and another file that supplies the timing to the video. The server-side system will integrate these into the host page template so that they run them together on demand. Until that authoring tool is developed, our editors can use the instructions provided here to subtitle a Quicktime version of the video and supply that subtitled version for download on the hosting page.
Viewing and previewing
For the GloPAD public interface we needed to use certain design techniques to allow viewers access to the video stored in the database, but also to allow them to see what is in the video without playing the whole thing. We developed the hosting page template, the "GloPAD Video Viewer," so that visitors to the database public interface could conveniently preview videos and not simply rely on the text of the item's record. Multimedia browing is one of the new features of the Internet that an online database such as ours must accomodate. The main features of this hosting page template are a storyboard of still images--so that viewers can see certain representative points in the video without playing it at all--and a fast-forward preview clip embedded in the hosting Web page so that viewers can "glance" at the video and decide whether they wish to play the full video or continue searching the database for some other video. (See the above screen shot or example #1). These two techniques we borrowed from the Open Video Project (http://www.open-video.org). For the Flash video instance of the GloPAD Video Viewer, the fast-forward preview clip is replaced by the Flash version of the video, letting viewers manually scrub through the video at their chosen pace and offering a option to download the video in its other format for presentation offline. We are also integrating into the Flash template the ability to make the thumbnails timed points in the video so that a viewer can click on a given thumbnail and the video will play from that point.
The Flash version of the GloPAD Video Viewer (subtitle regions are not visible)
