al soundtrack becomes unreadable or is damaged, the playback will automatically switch to the analog soundtrack. When the digital track is readable again, it will switch back. Also, in theaters that don't support digital sound, the analog track that can be read by standard Dolby SR equipped rooms.Dolby Digital: the 5.1 format that uses AC-3 compression. On DVD releases, you can have mono, stereo, or 5.1Sound tracks with AC-3 compression recorded on the "Dolby Digital" portion of the soundtrack. The data rate is variable, with 640kbps being common on film, but 384kbps being common in DVD-V releases.Dolby EX: This is a 6.1 system that has the same channels as a 5.1 system, but adds a center rear channel. Star Wars: The Phantom Menace was the first to use this. Some consumers receivers are offering this option now, with the center rear channel matrixes into the stereo surrounds.DTS: Digital Theater Systems. Above, we mentioned DTS in the sense of it being a codec. As a codec, it compresses 6 Channels of 20 bit 48kHz audio into a data rate of 1.4Mbps for roughly a 3:1 compression ratio. It also supports a 754kbps rate for DVD. In the theater, it is actually encoded onto a CD that plays back in sync with the film and is decoded into a very high quality 5.1 soundtrack. Its debut was with the release of Jurassic Park. The third thing that you need to know about DTS is that they have a large catalog of music CDs that play back on regular CD players with digital outs. When the digital output isfed into a DTS decoder, of which several DTS equipped consumer receivers and processors exist, you get a high quality 5.1 music format. Many people don't realize that there is a viable 5.1 music format available today with a catalog of a couple hundred popular CDs available.DTS-ES: This version of DTS is a 6.1 system with a center rear channel, similar to Dolby-EX....
