Where Shall We Go Next? - A Practical Guide to Video and Audio Compression - page 632

alongside the picture and this is the same data that would have gone out to air on a TV
system.
The DTS company that develops surround-sound systems has found a way to super-
impose subtitles at the time of projection. Because the company is well versed in synchro-
nizing multi-channel sound tracks to film and video, it becomes very easy to synchronize
a subtitle track.
The DTS system delivers the audio on a separate CD-ROM disk and that allows the
picture to be delivered on a single generic print of the movie that is the same all over the
world. The different language sound tracks are accomplished just by swapping the disk.
The subtitle data is synchronized and presented with an auxiliary projector, which
renders the overlay and projects it in addition to the normal picture. This is such a simple
idea, it is incredible no one thought of doing it years ago.
This approach is beneficial from the encoding point of view because text does not
encode very well and these subtitles would be in a different motion plane, which would
void the use of motion compensation in the area they occupy.

39.11 DVR Systems

The convergence of TV and information technology will continue with TV-Anytime and
other technologies, which add value to the viewing proposition.
The broadcast-TV industry is facing a scenario where appointment viewing is
replaced by cached playback systems modeled after the TiVo devices. This has major impli-
cations for interactivity and ensuring that programs are broadcast at scheduled times.

Figure 39-3 DTS subtitle-overlay projection.

DTS Cinema Subtitling: http://www.dtsonline.com/
PDC description: http://625.uk.com/pdc/