|
|
http://we.pcinlife.com/redirect.php?tid=1259597&goto=lastpost
' [' m# L5 M, ?% Dhttp://www.anandtech.com/video/showdoc.aspx?i=3643&p=10 * _9 s$ ^ v/ j& ?4 o y+ c
2 @, H0 Z/ M' X; S6 Z" d. |4 oThe Race is Over: 8-channel LPCM, TrueHD & DTS-HD MA Bitstreaming
/ n4 p/ ?0 ~& L4 v+ T! C% O, l
: U$ C8 U6 q$ HIt's now been over a year since I first explained the horrible state of Blu-ra I& v/ [: B8 c
y audio on the PC. I'm not talking about music discs, but rather the audio com/ F S5 ]. D( b9 U5 v5 y
ponent of any Blu-ray movie. It boils down to this: without an expensive sound- O+ ^! c- q% `) s. S- u1 ^
card it's impossible to send compressed Dolby TrueHD or DTS-HD Master Audio s, \! D' e3 |8 E0 c t
treams from your HTPC to an AV receiver or pre-processor. Thankfully AMD, Inte
( h' o X% {6 N5 M: ^0 `l and later NVIDIA gave us a stopgap solution that allowed HTPCs, when equippe
2 D/ B/ _- ~ K- @( D4 M t3 |d with the right IGP/GPU, to decode those high-definition audio streams and se
4 _. y7 Z4 d4 X5 |# Y- Ond them uncompressed over HDMI. The feature is commonly known as 8-channel LPC. p4 U- V' r' s+ i5 V
M support and without it all high end HTPC users would be forced into spending$ m: W* H6 b- H6 N' a0 \- J
another $150 - $250 on a sound card like the Auzentech HomeTheater HD I just # `8 n' v8 c' ^% W' C% h0 n% n1 J
recently reviewed. * S6 s! ]4 R# y8 U! Q4 p
* c% H9 k5 @+ \% j
For a while I'd heard that ATI was dropping 8-channel LPCM support from RV870
7 Y- N3 _& I" k' _$ }because of cost issues. Thankfully, those rumors turned out to be completely u% R5 @8 \ o, D N; l
ntrue. Not only does the Radeon HD 5870 support 8-channel LPCM output over HDM% E9 i) X6 r' N( W: M; _+ Y
I like its predecessor, but it can now also bitstream Dolby TrueHD and DTS-HD
6 e D+ C. {) VMA. It is the first and only video card to be able to do this, but I expect ot
9 `- A* o' Z5 N/ ]7 A- }( P7 G/ @hers to follow over the next year. - @. _: S# X( J1 a4 Q, h# n
% Q/ _1 O, ?0 q) g; L4 W* nThe Radeon HD 5870 is first and foremost a card for gamers, so unless you're b
: ~* t# V1 J* m, A# z: yuilding a dual-purpose HTPC, this isn't the one you're going to want to use. I
# l9 z/ h z% B9 w( I; y7 s$ b Pf you can wait, the smaller derivatives of the RV870 core will also have bitst
" q4 B. ?( Z3 L; K( ]5 Freaming support for TrueHD/DTS-HD MA. If you can't and have a deep enough HTPC
) _: b- C" `5 H7 q6 Kcase, the 5870 will work. ; L/ G* P2 B; x3 l9 @8 B, a, H& l$ ^( e
y% V; l1 Q) ?2 p% @In addition to full bitstreaming support, the 5870 also features ATI's UVD2 (U/ @& m) g# N' z6 s8 m
niversal Video Decoder). The engine allows for complete hardware offload of al
" t2 D/ A4 `) {l H.264, MPEG-2 and VC1 decoding. There haven't been many changes to the UVD2
, \8 S& c4 z N- x* r( Bengine; you can still run all of the color adjusting post-processing effects a$ M! u, ~" r1 V/ g/ m4 {: z
nd accelerate a maximum of two 1080p streams at the same time.
3 m: }& z$ W6 f1 y7 Q% u1 `; ?6 x, U
ATI claims that the GPU now supports Blu-ray playback/acceleration in Aero mod. r* e2 |. n+ g: o
e, but I found that in my testing the UI still defaulted to basic mode.! d9 p8 `2 {) ^
0 F2 S T2 ]9 N, |3 |To take advantage of the 5870's bitstreaming support I had to use a pre-releas; M; c* s) D' t* _" V. I# K8 R
e version of Cyberlink's PowerDVD 9. The public version of the software should1 O! C/ b: U; N: q' C+ C. {9 l6 H
be out in another week or so. To enable TrueHD/DTS-HD MA bitstreaming you hav% s2 \8 o7 G# V5 b. B$ ?
e to select the "Non-decoded high-definition audio to external device" option
& d! m9 L1 ?) N, [- Win the audio settings panel:' { A; d8 F j& D& ?
1 n1 s# p! a0 i7 Z) z3 {With that selected the player won't attempt to decode any audio but rather pas* T$ O, B! Y3 X' g. ~
s the encoded stream over HDMI to your receiver. In this case I had an Integra3 Y" B8 r! B* Y
DTC-9.8 on the other end of the cable and my first test was Bolt, a DTS-HD MA; y8 g8 O7 H5 T# h1 N5 U
title. Much to my amazement, it worked on the first try:
0 y0 a& u# F9 e2 p
+ F- q* z1 V; ^1 Z4 g+ m5 dNo HDPC errors, no strange player issues, nothing - it just worked. + F$ a+ s( e0 Z
* m( X; q1 x& _5 ~0 h! i7 `Next up was Dolby TrueHD. I tried American History X first but the best I coul1 n1 {. A7 X3 G1 T# N- `$ I* T
d 【请注意文明用词】 of it was Dolby Digital. I swapped in Transformers and found the sam
% }+ X6 }. ^- z, Je. This ended up being an issue with the early PowerDVD 9 build, similar to is0 r% O6 E- V7 e2 y
sues with the version of the player needed for the Auzentech HomeTheater HD. S2 J" Z" c' {( k# K
witching audio output modes a couple of times seemed to fix the problem, I now
. p! q; ]- d- F1 a, z' \, k; [had both DTS-HD MA and Dolby TrueHD bitstreaming from the Radeon HD 5870 to m9 K) m/ F! X; \& w% S2 |
y receiver.1 Z$ n) y. A5 n% n* R; f. F
* l$ b% D! Z# f
One strange artifact during my testing was the 5870 apparently delivered 1080i
7 q6 H5 J/ y. m! G9 Soutput to my JVC RS2 projector. I'm not exactly sure what went wrong here as
7 }8 U. J% _' ~' T3 z1080p wasn't an issue on any other display I used. I ran out of time before I
& L! G( [9 H4 X+ l9 M9 H+ Zcould figure out the cause of the problem but I expect it's an early compatibi0 ^- R) @" g+ {2 \6 a$ Z
lity issue. : S. d* f& {5 |' K) s- |, q
6 `2 b, V- J( W" u% ?. M7 JI can't begin to express how relieving it is to finally have GPUs that impleme' y; K, V8 p" ]$ O
nt a protected audio path capable of handling these overly encrypted audio str
9 G8 N7 o) M7 r* beams. Within a year everything from high end GPUs to chipsets with integrated
+ Q# b" I. N6 Z7 D) Kgraphics 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