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Originally Posted by dj_stick
to be succint here, no, it doesn't
if the Dolby Digital audio is stereo, it's played as stereo, UNLESS, the receiver upmixes it to 5.1, giving a pseudo-surround, which is not true surround - same with any source being upmixed - 5.1 into 7.1 is still 5.1 upmixed, it's NOT true 7.1
i hope that helps to clear up alot of the sh*t that's going around with all the different formats
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To be precise, it is not upmixing, it is matrix(ing).
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Matrix decoder is an audio technology where a finite number of discrete audio channels (eg. 2) are decoded into a larger number of channels on play back (eg. 5). The channels are generally, but not always, arranged for decoding by an encoder, and decoded for playback by a decoder.
The notation for matrix encoding consists of the number of discrete audio channels separated by a colon from the number of decoded channels. For example, two discrete channels decoded to four-channels would be notated:
2:4
Five discrete channels decoded to six channels would be notated:
5:6
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-and It sounds pretty good too, clicking back and forth between 5.1 and matrixed 7.1 with a 5.1 signal sounds pretty good. The surround channels sound more even and full in the room - I know it is not true 7.1 though in that mode.
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Dolby Digital EX
EX adds an extension to the standard 5.1 channel Dolby Digital codec in the form of matrixed rear channels, creating 6.1 or 7.1 channel output. However, the format is not considered a true 6.1 or 7.1 channel codec because it lacks the capability to support a discrete 6th channel unlike the competing DTS-ES codec.
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For instance my cable box -- comes in via HDMI or optical cable. In the case of 5.1 to 7.1, it (the AVR, not the box) is matrixing the SR and SL to create four surround channels.. SL, SR, and SBL, SBR, or just one rear "center surround" for 6.1. (surround left, right, back left, back right).
BTW, on my Yamaha rx-v661- it has a menu where it tells you how many audio channels are coming in via HDMI or optical, and the sampling and bit-rate. Sometimes it has all 5.1 shown coming in, sometimes only 2 are shown depending on the channel (the TV channel Nothing comes out of the rears on news channels, etc.), but it still outputs 5.1 channels if the movie is in 5.1. It sounds like the rear channels are playing different sounds than the front three, or nothing at all depending on what's happening in the movie, etc. It is not as good as true 5.1, but it is definitely not just stereo upmixed to 5.1. There are surround channels, and the AVR separates the LFE in that case.
For true 7.1-- via BD or HD DVD
In my case- the AVR does not Decode
Dolby TrueHD though, but it does process 7.1 multi-channel PCM via HDMI -or 8 discrete channels from a player that has that capability.
That was my point though- The AVR doesn't have to be able to decoded it, as long as the player can do it- output to the AVR and the AVR output it to 8 separate channels. Some non TrueHD AVRs can, some can't. Most good AVRs now do both if they are HDMI and 7.1 capable... Last year that wasn't the case.
Notice the 8 separate channel inputs.. (i think you use zone 2 out for SBL & R) or something like that. Or PCM via HDMI.
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8 Ch Ext Input
8 additional input jacks for discrete multi-channel input. Front (Left, Center, Right), Rear (Surround Left & Right, Surround Back Left & Right) and Subwoofer
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RX-V661
(wiki)
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Connecting a TrueHD source to a TrueHD receiver requires a digital-link capable of transporting either the encoded bitstream (up to 18 Mbit/s), or the unpacked linear-PCM audio (>35 Mbit/s). HDMI 1.1 (and higher) can transport multichannel PCM-audio, and therefore can transport an unpacked TrueHD audiotrack.
HDMI-equipped players can internally decode TrueHD to LPCM, and output the LPCM over an HDMI 1.1 (or higher) interface; all HD DVD players and the PlayStation 3 currently support this.[2] If a player cannot internally decode TrueHD, it can transport the bitstream over HDMI 1.3 to a receiver capable of decoding it; this feature is now supported on Toshiba HD-A35 HD DVD player, as well as the Samsung 1400 BD player with a firmware upgrade. HD DVD players can also transcode the TrueHD bitstream into a different legacy format (such as Dolby Digital or DTS), providing a high-quality approximation of TrueHD audio over a legacy TOSLINK cable for those that do not have HDMI.
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