Current surround formats

Revision as of 19:25, 14 December 2008

http://www.dolby.com/

http://www.dts.com/

http://www.thx.com/

Adapted from this sticky on the OCAU forums.

"Obviously this should have been done a while ago..." - Tony

Encoding Formats

• DTS 5.1 - L/C/R + SL/SR + LFE (768 or 1,536k/s)

• DTS '6.1' ES-Matrix - L/C/R + SL/SR + LFE + matrix Rear Centre

Note: Obviously they call it "6.1" but it is only 5.1 in reality.

• DTS 6.1 ES-Discrete - L/C/R + SL/SR + LFE + discrete Rear Centre

• Dolby Digital 5.1 - L/C/R + SL/SR + LFE (384 or 448k/s)

• Dolby Digital 5.1 EX - L/C/R + SL/SR + LFE + matrix Rear Centre

• Dolby Digital Plus

Multi-channel audio and higher audio quality is made possible using Dolby Digital Plus. BD-Video supports up to 7.1 channel output.

• Dolby TrueHD

Dolby TrueHD is a very high quality audio format that reproduces the studio master audio. BD-Video supports up to 7.1 channel output.

• DTS-HD

DTS-HD is a high-quality, sophisticated audio format used in movie theaters. Previous DTS Digital Surround-compatible equipment can play DTS-HD as DTS Digital Surround audio. BD-Video supports up to 7.1 channel output.

• DTS-HD High Resolution Audio

This is a signal format achieved by improving the previous DTS, DTS-ES and DTS96/24 formats. It is compatible with sampling frequency 96 kHz/48 kHz. BD-Video supports up to 7.1 channel output.

• DTS-HD Master Audio

This is a lossless audio format and compatible with 96 kHz/7.1ch or less. In addition, faithful reproduction of the master audio is enabled using lossless audio

Decoding Format

• THX EX Surround 7.1 - L/C/R + SL/SR + LFE + two matrix rear centres; depending on the product, the matrix rears can be summed mono or derived stereo. This is applied to Dolby 5.1 EX titles. Later Dolby 5.1 EX was introduced as THX 7.1 was too expensive for the majority of systems.

Certifications

• THX Ultra2 - update for 7.1 systems, rated for 3,000+ cu.ft rooms

• THX Ultra - 5.1 systems, rated for 3,000+ cu.ft rooms (same as the old THX cert.)

• THX Select - 5.1 or 7.1 systems, rated for 2,000+ cu.ft rooms

Other THX formats aren't worth anything.

Current virtualising formats for two channel

• SRS Circle Surround 5.1 ("CS 5.1") - derived centre + SL/SR + LFE

• Dolby Pro Logic II - derived centre + SL/SR + LFE (Dolby Pro Logic II is also a matrix encoding format.)

• dts Neo 6 - derived centre + SL/SR + LFE

• Logic 7 - derived centre + SL/SR + SBL/SBR + LFE can be applied to either stereo or 5.1/6.1 formats depending on sophistication of processor. Limited to Lexicon and Harmon Kardon equipment.

You will often see

• Linear PCM 48kHz audio at 16-bit (1,536k/s) or at 24-bit (2,304k/s).

• Dolby Digital 2.0 Stereo or Surround at anything from 96 to 448k/s.

There is also an emerging dts 24/96 format at 768k/s with 5.1 or 6.1 channels. I think they call it "dts 96/24".

SACD and DVD-A

• SACD - signal frequecy response up to 100kHz. Normal Cds only 20 KHz.

SACD are found in most new Philips and Sony Dvd players.

• DVD-A - Sampling rate up to 192kHz.

DVD-A uses the same coding method of Cds by extending the word length from 16 to 24 bit. Thus the improved performance.

External Links

• General surround formats info - Every format in detail
• DTS Whitepaper