|
|
http://we.pcinlife.com/redirect.php?tid=1259597&goto=lastpost
6 o: }, }% E6 G; r/ Fhttp://www.anandtech.com/video/showdoc.aspx?i=3643&p=10
2 {3 `$ i0 ?, ^$ c0 L* S, m# D: c% t. K7 I0 C1 l& a
The Race is Over: 8-channel LPCM, TrueHD & DTS-HD MA Bitstreaming
) V/ t! O2 w; `. P' a7 \1 [$ e
2 C$ i7 `9 m8 FIt's now been over a year since I first explained the horrible state of Blu-ra8 f5 t& N9 d' r0 a
y audio on the PC. I'm not talking about music discs, but rather the audio com: P1 [0 l* }% E; c0 K, l& }
ponent of any Blu-ray movie. It boils down to this: without an expensive sound/ o3 { ^* {& ^6 W
card it's impossible to send compressed Dolby TrueHD or DTS-HD Master Audio s
: _( r4 V( N# V! B: E: h- ]treams from your HTPC to an AV receiver or pre-processor. Thankfully AMD, Inte
7 |% e; z' L; n% c0 ]7 e5 t7 ul and later NVIDIA gave us a stopgap solution that allowed HTPCs, when equippe+ D/ F! f; k7 r6 A& O( X
d with the right IGP/GPU, to decode those high-definition audio streams and se$ P& {) C/ o) ^" v+ x2 Z1 P
nd them uncompressed over HDMI. The feature is commonly known as 8-channel LPC- p( j, K7 V% k3 T
M support and without it all high end HTPC users would be forced into spending
5 M& `2 \. v# a- X# G. nanother $150 - $250 on a sound card like the Auzentech HomeTheater HD I just , A% q5 E' M, p: t5 e+ `8 ^: W
recently reviewed.
2 k! [: F' e# v( O+ D7 [) P" C" P4 A8 Q* O/ m9 i6 V2 o8 O
For a while I'd heard that ATI was dropping 8-channel LPCM support from RV870
) Q% ?4 N p1 A4 B! X$ M0 ubecause of cost issues. Thankfully, those rumors turned out to be completely u: q' [9 E+ Y& y4 a
ntrue. Not only does the Radeon HD 5870 support 8-channel LPCM output over HDM2 r6 u) L/ ^) F) M R# g6 s# v
I like its predecessor, but it can now also bitstream Dolby TrueHD and DTS-HD
% i$ ^. U% i2 E6 C5 xMA. It is the first and only video card to be able to do this, but I expect ot
* B7 l5 D, Y; m& s* H- ]! a# k8 mhers to follow over the next year.
, K4 S; t) K4 b, v7 k l3 Q3 [# I' Z6 s: Z T& T& ^3 X2 i
The Radeon HD 5870 is first and foremost a card for gamers, so unless you're b
! n" V5 e a6 s; z7 f9 n2 k+ Z7 Q3 [" huilding a dual-purpose HTPC, this isn't the one you're going to want to use. I
; O3 r1 }- o$ n/ G4 ^f you can wait, the smaller derivatives of the RV870 core will also have bitst' I6 z; Z. U, J. \8 | A) W/ _% X' H
reaming support for TrueHD/DTS-HD MA. If you can't and have a deep enough HTPC9 u, v, Z" \ l) Y: e' Q' K; x' H
case, the 5870 will work.
' N |. }7 b( L
. N9 _$ d9 i* }; C6 T. HIn addition to full bitstreaming support, the 5870 also features ATI's UVD2 (U
4 b4 i0 P+ `7 z& b# j" Z, zniversal Video Decoder). The engine allows for complete hardware offload of al/ P* _0 V+ P) n$ \; Q
l H.264, MPEG-2 and VC1 decoding. There haven't been many changes to the UVD2 9 Q" \3 t2 |- ^2 z# K" ?
engine; you can still run all of the color adjusting post-processing effects a
% Q* v" @3 l0 |; y. {2 _nd accelerate a maximum of two 1080p streams at the same time.6 r+ p' K4 }2 Y* m' v/ ]- S w
' R' S" m \ T- U
ATI claims that the GPU now supports Blu-ray playback/acceleration in Aero mod
3 e# c3 s- a# P( \e, but I found that in my testing the UI still defaulted to basic mode.8 @2 N* S5 M( d5 Z+ D
# y8 u; @. v4 X1 R4 S
To take advantage of the 5870's bitstreaming support I had to use a pre-releas
4 Y0 u6 Z5 T$ [e version of Cyberlink's PowerDVD 9. The public version of the software should; s% A) P, z. s5 A/ F7 H- B
be out in another week or so. To enable TrueHD/DTS-HD MA bitstreaming you hav$ H, u; n8 r, g$ w
e to select the "Non-decoded high-definition audio to external device" option
" i1 r" x% V/ H/ }6 zin the audio settings panel:
+ ^% K6 a* l; A1 j# e9 { ?% o( g, v" }7 @/ [
7 J7 ~! z0 M1 r, w' B: c: n# VWith that selected the player won't attempt to decode any audio but rather pas
, d# M. q& i0 T# xs the encoded stream over HDMI to your receiver. In this case I had an Integra7 C9 J: c0 p0 i9 U3 D2 m
DTC-9.8 on the other end of the cable and my first test was Bolt, a DTS-HD MA
8 e+ C* C. p p% {, Z4 y3 u3 I# |title. Much to my amazement, it worked on the first try:
0 i1 V% O Z" W' I2 F0 J w/ ^ I# f
1 Q) W/ v5 G2 n* Q" g) qNo HDPC errors, no strange player issues, nothing - it just worked. : o/ J+ Z/ \, |& V
; P* j& L+ x. ^: _
Next up was Dolby TrueHD. I tried American History X first but the best I coul t' b7 w& H0 u
d 【请注意文明用词】 of it was Dolby Digital. I swapped in Transformers and found the sam
$ p: D* j7 B4 G# E; a, H# d" te. This ended up being an issue with the early PowerDVD 9 build, similar to is
. }" `# G" {/ qsues with the version of the player needed for the Auzentech HomeTheater HD. S0 J9 G* g ^6 p) L3 ^9 v
witching audio output modes a couple of times seemed to fix the problem, I now
1 {& k; \' b5 E4 S; y8 m/ g6 f3 [had both DTS-HD MA and Dolby TrueHD bitstreaming from the Radeon HD 5870 to m6 Y. j/ G; C- M% l, }; E( D2 ]' q
y receiver.1 D- q" o3 W ?, y
$ F7 `3 M$ s5 n5 ^2 f, c: J
One strange artifact during my testing was the 5870 apparently delivered 1080i& C" A; M) c0 ]
output to my JVC RS2 projector. I'm not exactly sure what went wrong here as 0 p. L- @( C$ I. Q% u) p; |: t S
1080p wasn't an issue on any other display I used. I ran out of time before I
& d8 Z8 `# L; lcould figure out the cause of the problem but I expect it's an early compatibi4 M; V, q' t* V9 n% j; F
lity issue. 1 z: _8 e; Z: p5 m2 V
; e# O! K9 S6 P( x% ?( ^
I can't begin to express how relieving it is to finally have GPUs that impleme
8 y& Q- @0 p+ A& {' P7 Jnt a protected audio path capable of handling these overly encrypted audio str
$ R* Y! X& f7 ?6 b/ ]1 u# `! leams. Within a year everything from high end GPUs to chipsets with integrated 1 z7 x- F; ]8 b+ E4 ^- G
graphics will have this functionality. |
|
IP卡
狗仔卡
发表于 2009-9-22 14:33
QQ好友和群
收藏
分享
好贴
烂贴
提升卡
置顶卡
沉默卡
喧嚣卡
变色卡
显身卡