Video Asylum

Posted by Joe Murphy Jr (i) on August 10, 2001 at 17:37:48

In Reply to: DTS! posted by Brian Hueske on August 10, 2001 at 09:46:03:

as there are some incorrect statements in your reply. For instance, Dolby Digital is full range on all channels, except the LFE or .1 channel. It is common for the LFE to be cut off between 100Hz and 120Hz. The same goes for DTS, except 80Hz in the LFE channel. As for the surrounds in DTS, they get frequencies from 80Hz on up -- frequencies below 80Hz are redirected to the sub. As far as what happens in the mix to the higher frequencies, you may want to go to www.dtsonline.com and find the section that includes the DTS vs Dolby Labs letters (Dolby's paper, DTS's response to Dolby, etc.). WidescreenReview magazine also ran these letters in the mag and online (.com). DTS is not uncompressed: it is compressed. It is, however, much less compressed than Dolby Digital (usually between 10 and 12:1). The DTS compression is between 3 and 6:1. As for the space issue and special features, many of those early discs could have included the extras. The question was, "how will DTS be accepted by the consumer?" or, the polite "decoded" version -- "will we make enough money off of this to feed our greedy asses?". The DVD spec says that either PCM or Dolby Digital must be included on a DVD-V. However, Dolby Digital doesn't just mean 5.1 sound. It could be just 2 channels of audio with Dolby Digital encoding. The early DTS DVDs from Universal had this form of Dolby Digital, which I believe are at a bitrate if 192kb/s. DTS on these discs were at 1.54Mb/s, though now DTS is commonly encoded at 754kb/s. Dolby Digital for 5.1 is either at 448kb/s or 384kb/s, depending on the studio. For comparison, two channel music on a CD is at 1.4Mb/s. By the way, DTS can go up to over 4Mb/s and include eight channels of audio.