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http://we.pcinlife.com/redirect.php?tid=1259597&goto=lastpost. C# ~, v: y% Z* \" {
http://www.anandtech.com/video/showdoc.aspx?i=3643&p=10 , Q* R& h7 E- ?2 @6 b7 W
7 `' C+ \7 ?& S1 SThe Race is Over: 8-channel LPCM, TrueHD & DTS-HD MA Bitstreaming
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It's now been over a year since I first explained the horrible state of Blu-ra# ^; y4 r/ ~) F8 Q
y audio on the PC. I'm not talking about music discs, but rather the audio com$ ]9 d7 J7 B; H5 H& G: @8 `; U
ponent of any Blu-ray movie. It boils down to this: without an expensive sound
2 K* g% |& y" I% scard it's impossible to send compressed Dolby TrueHD or DTS-HD Master Audio s
3 [5 D' h- O7 U9 x. i$ otreams from your HTPC to an AV receiver or pre-processor. Thankfully AMD, Inte
, c0 {) R" v7 K/ F. ol and later NVIDIA gave us a stopgap solution that allowed HTPCs, when equippe+ e3 J P- Z4 ^ J
d with the right IGP/GPU, to decode those high-definition audio streams and se
/ s4 }( M4 c6 S; Y7 Q2 Fnd them uncompressed over HDMI. The feature is commonly known as 8-channel LPC& R- I/ G/ Z! ~- Y5 t4 v
M support and without it all high end HTPC users would be forced into spending1 I# q v5 c$ {6 E" m9 u d( _
another $150 - $250 on a sound card like the Auzentech HomeTheater HD I just
, _+ @, e8 k2 M: ~recently reviewed.
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For a while I'd heard that ATI was dropping 8-channel LPCM support from RV870 3 X! S( L- L+ H& \. S. O
because of cost issues. Thankfully, those rumors turned out to be completely u p4 S) G4 f- M6 j( ^6 ]5 i
ntrue. Not only does the Radeon HD 5870 support 8-channel LPCM output over HDM) K: G+ ]( I( M* R
I like its predecessor, but it can now also bitstream Dolby TrueHD and DTS-HD 4 A' v5 v3 E0 k9 E
MA. It is the first and only video card to be able to do this, but I expect ot1 _3 N: W5 y. Z
hers to follow over the next year.
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The Radeon HD 5870 is first and foremost a card for gamers, so unless you're b
* D6 Y( E6 f* C0 ^, r3 X; wuilding a dual-purpose HTPC, this isn't the one you're going to want to use. I
: k! R1 v4 @# Z9 |4 }' z m. Z! Af you can wait, the smaller derivatives of the RV870 core will also have bitst% L$ V9 T) J1 u9 s+ @. H: W Q
reaming support for TrueHD/DTS-HD MA. If you can't and have a deep enough HTPC9 X3 ~; w5 |" W
case, the 5870 will work. ' K1 h2 q z# E! p7 J1 d S
8 `3 w# A! h4 E9 N4 V& F" T
In addition to full bitstreaming support, the 5870 also features ATI's UVD2 (U
, p2 l0 A N; {* o ?# mniversal Video Decoder). The engine allows for complete hardware offload of al
2 k: C, O% Y8 N3 \l H.264, MPEG-2 and VC1 decoding. There haven't been many changes to the UVD2 3 n0 n8 d4 }- J1 s/ a$ x
engine; you can still run all of the color adjusting post-processing effects a" L% l0 S' D& ~5 x' {# ] }/ i
nd accelerate a maximum of two 1080p streams at the same time.
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ATI claims that the GPU now supports Blu-ray playback/acceleration in Aero mod
! _5 S5 i1 R6 w* I) s; je, but I found that in my testing the UI still defaulted to basic mode.
4 E, M; u8 Y1 M' y2 l
# b% E: B [9 O" KTo take advantage of the 5870's bitstreaming support I had to use a pre-releas
2 l) s" k4 G3 v W xe version of Cyberlink's PowerDVD 9. The public version of the software should& R9 T" I7 j! Z7 D" {) s
be out in another week or so. To enable TrueHD/DTS-HD MA bitstreaming you hav
3 m( z8 a1 D) T- j' V; n' be to select the "Non-decoded high-definition audio to external device" option + }2 @1 k. ]; i8 z" U* ?1 u
in the audio settings panel:+ {: Z* q+ o P- U' J- e( ~4 \# |
/ u. f2 @' a+ ^5 ?With that selected the player won't attempt to decode any audio but rather pas7 J. H3 o! E/ o1 U
s the encoded stream over HDMI to your receiver. In this case I had an Integra0 a0 n; K# o! X& ~
DTC-9.8 on the other end of the cable and my first test was Bolt, a DTS-HD MA
\, F8 I; Z' S9 Vtitle. Much to my amazement, it worked on the first try:: Q8 B1 Q7 `* X, f) @
. D5 u( a: \! b) u6 O, }# FNo HDPC errors, no strange player issues, nothing - it just worked. ; R& m0 v5 B1 o
4 R7 i3 k7 G1 w
Next up was Dolby TrueHD. I tried American History X first but the best I coul
8 y( _$ c. i3 p* f5 Ad 【请注意文明用词】 of it was Dolby Digital. I swapped in Transformers and found the sam
& J" `( ]/ Z% h i) se. This ended up being an issue with the early PowerDVD 9 build, similar to is+ b& v/ s2 G5 P$ E
sues with the version of the player needed for the Auzentech HomeTheater HD. S
t6 K4 D! k% _5 R( b# @# r pwitching audio output modes a couple of times seemed to fix the problem, I now
6 e0 C+ q2 r. G) k3 thad both DTS-HD MA and Dolby TrueHD bitstreaming from the Radeon HD 5870 to m( f# e& T* i5 m& W: h
y receiver.; Q) o+ F, A6 m, M
2 Q4 F4 q6 J5 i, a
One strange artifact during my testing was the 5870 apparently delivered 1080i
) A( U8 x, ~' b' goutput to my JVC RS2 projector. I'm not exactly sure what went wrong here as 8 {# S% g. \3 O5 @. Q( N
1080p wasn't an issue on any other display I used. I ran out of time before I
; A. b& d2 W2 l2 N% T8 xcould figure out the cause of the problem but I expect it's an early compatibi3 e4 _1 J. `+ Z. L* Z; z+ \
lity issue. / k; O. h6 o) ?3 |# T M
: ?9 J/ y& ?9 M1 x- q: k* `( S9 yI can't begin to express how relieving it is to finally have GPUs that impleme% K* C8 `& t8 C% t0 v$ @& `
nt a protected audio path capable of handling these overly encrypted audio str( s4 | v# S# @, r# z% x
eams. Within a year everything from high end GPUs to chipsets with integrated : c2 K' q! V) C' w! V
graphics will have this functionality. |
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