DTS IN MOVIE THEATER
 
DTS, or Digital Theater Sound, is a motion picture sound system format that
stores a digital soundtrack on separate CD-ROM discs.
 
The 35mm prints released for DTS films have a normal, conventional analog
optical soundtrack.  The same prints can thus be played in DTS-equipped and
non-DTS-equipped theaters; studios and distributors only need to maintain a
single inventory of prints.  The analog soundtrack also provides a
fail-safe backup for DTS-equipped systems.
 
The only unusual addition to a DTS print is an optical timecode track,
which is squeezed in between the optical sound track and the film frame.
The DTS system includes an optical timecode reader which is mounted onto the
projector.  Then, for each film frame, a timecode is read off
the print, and the corresponding digital soundtrack info is retrieved off
of the CD-ROM.  
 
 
DTS IN HOME APPLICATIONS
 
 -> Introduction
DTS especially usedin high-definition audiotracks in Video or audio.
The majority is used in DVDvideo.
 
DTS is a 5.1 sound format like Dolby Digital. But, there are other alternatives, like DTS-ES, encoded on 7 channels,so in 6.1.
 
 -> Compression
 
The audio signal undergoes a succession of treatments :
 . analyze spectral by filtering 32 bands of equal width (750 Hz)
 . elimination of the nonrelevant bands
 . dynamic binary allowance (i.e. that the number of bits of the quantification is variable 2 to 15 bits).  The precision of the resolution is given on each tape to maintain inaudible the noise of the quantification
 . a FFT supplements the analysis by band, especially for the low frequencies
 . one calculates the maximum amplitude by intervals of time (from 8 to 24 ms) in order to determine a scale factor, i.e. a multiplying coefficient coded on 6 bits
 . the whole is multiplexed and put in screens
 
 -> Specification
 
The compression ratio is about 4, contrary to Dolby digital which is to 12.
Thus, a track DTS is less compressed, and is of better quality, but it occupies more place on the support.
 
Channels in DTS have a bandwith of 20Hz to 20KHz.
The data rate of these channel is about 1536 kpsc (contrary of 448 kpsc maximum and a average of 384 kpsc for Dolby Digital).
DTS soundtrack is used a quantification of 20 bits, contrary of the 16 of dolby digital, with a sampling rate of 44.1 KHz or 48 KHz.
 
 
With these specification DTS are the best way to encode a movie soundtrack, but there is a little problem to the expansion of this format, it's the space used by DTS.
 
For answer to this problem, DTS have decrease the quality of his format. They have down their data rate to 768 Kbps, with this data rate, we can found DTS soundtrack on DVD.
But even with this data rate, a DTS soundtrack is better quality than the same encoded in Dolby digital.
 
 
 -> Other application.
 
But DTS, is also used in audio medium, like CD, and of course in DVD-Audio.
The futur of DTS is a evolution of the current format, the quantification ratio and the sampling rate is increased to 24 bis and 96 KHz.