Oftentimes, clients who need captioning may not have a video file or tape master to provide a caption service company. The only source video is found as a completed DVD-Video master. This poses many challenges for captioners, because they have to find a way to access the video which is found on the DVD disc. Furthermore, to caption a DVD, a new master must be made with a DVD authoring system. This article touches upon many of these technical hurdles, and how to get past them to provide your clients with a closed captioned DVD master.
Accessing the video found inside the DVD
The first thing to do is to move the video files from the DVD disc onto the computer hard drive. There is specialized software that can help access the audio and video inside of the DVD. One of the most effective is a software product called MPEG Streamclip ( free download from www.squared5.com ). This software allows you to extract the MPEG-2 video in its native format to the hard drive. Also, MPEG Streamclip can convert the MPEG-2 video to a video file that is friendlier for playback and closed captioning in CPC software such as .AVI or .MOV.
Creating a proxy video to work with CPC software
DVD-Video uses MPEG-2 formatted video files in a special VOB file structure. These cannot be used to caption a video. They must be converted to a proxy video file such as .AVI, .MOV, or MP4. Using software such as Handbrake, Turbo 264HD, or MPEG Streamclip, non-copyrighted DVD-Video can be easily converted of a proxy video file that is friendly to CPC software.
How to burn a new copy of the DVD with captions
To create a new DVD Master with closed captioning, DVD Authoring software should be used. Many DVD burning software products do not have the ability to make a captioned DVD. Special authoring software should be used. We recommend Adobe DVD Encore or DVD Studio Pro. Both of these software packages can accept a caption data file to marry with the DVD video.
The standard for caption data file is the .SCC (Scenarist Closed Caption) file. This caption data file is created with CPC software and can be imported to both DVD Studio Pro and DVD Encore. The captioning text cannot be checked until the DVD is compiled and/or burned. For best results, it’s important to use a set top DVD-Player connected via analog connections to a TV.
What kind of DVD blank media should be used?
From experience, we have found that DVD-R is the most compatible DVD-Video media available. At the store you may also see DVD-RW and DVD+R. Many older DVD players are only compatible with DVD-R. We recommend using the most compatible blank DVD-Video media. Check to see if your hardware manufacturer recommends a specific type of media.
HDMI doesn’t display captions
Many set top DVD players now have HDMI ports that can connect to HDTV sets. However, when testing captions on a DVD, HDMI connections should be avoided. According to the specifications, HDMI does not support closed caption data. It is imperative that an analog connection be made in order to properly check the captioning. Also, TV sets can only enable closed caption setting when analog connections are active when receiving a signal from a DVD player. Some DVD players have a progressive mode. Make sure that “Progressive” is not enabled or the player will not render the captioning data properly.
Checking captioning data with software DVD-ROM players
Oftentimes, there is no access to a set top DVD player, and the DVD-ROM on a computer is the only way to play a DVD-Video. This means that DVD player software must be installed and used to view the DVD. It is imperative that the DVD player software used to playback the video have a way to turn the captions on in order to properly check the disc. If the user does not have software installed, we recommend VLC player which is a free download from www.videolan.org .
We have yet to see software that properly decodes DVD closed captioning like a standard TV set does. Even VLC will only render the caption text at the bottom center of the screen and ignores any positioning and formatting that a TV would render.