|
|
http://we.pcinlife.com/redirect.php?tid=1259597&goto=lastpost3 ^: o, Q6 Z' k5 G
http://www.anandtech.com/video/showdoc.aspx?i=3643&p=10
7 b4 E1 H$ K# p. X8 r
, w7 v. O, L$ _7 l: p l3 ~4 gThe Race is Over: 8-channel LPCM, TrueHD & DTS-HD MA Bitstreaming
! f: G6 m4 W" z5 [2 F( c0 x, F; W- h9 t/ Q7 y
It's now been over a year since I first explained the horrible state of Blu-ra
7 l' u% V1 X) x1 z- Ey audio on the PC. I'm not talking about music discs, but rather the audio com6 Z# w G) W( J; `) G
ponent of any Blu-ray movie. It boils down to this: without an expensive sound
6 X# R. ]- x0 X; @card it's impossible to send compressed Dolby TrueHD or DTS-HD Master Audio s
# G4 z; L" S- `treams from your HTPC to an AV receiver or pre-processor. Thankfully AMD, Inte8 \4 C5 x$ a1 |5 ~& U, r; h
l and later NVIDIA gave us a stopgap solution that allowed HTPCs, when equippe' h1 {# y' B; P
d with the right IGP/GPU, to decode those high-definition audio streams and se
: c% Y a$ L mnd them uncompressed over HDMI. The feature is commonly known as 8-channel LPC0 s$ h4 a* Y* q( ]* T' O5 N% s
M support and without it all high end HTPC users would be forced into spending" P- W" K, e9 j+ j
another $150 - $250 on a sound card like the Auzentech HomeTheater HD I just
/ \( j/ `' _( Mrecently reviewed.
) S& \, b$ B) C+ t$ g
' Y. w" K% L. k9 dFor a while I'd heard that ATI was dropping 8-channel LPCM support from RV870 : F6 }0 C6 L% J8 @: k! h
because of cost issues. Thankfully, those rumors turned out to be completely u
! d5 y/ d* { u% [7 h( Tntrue. Not only does the Radeon HD 5870 support 8-channel LPCM output over HDM' a8 s, o: `: e% d: _# d; A
I like its predecessor, but it can now also bitstream Dolby TrueHD and DTS-HD 2 x: Q5 _, h7 ^
MA. It is the first and only video card to be able to do this, but I expect ot7 C. _ } {' w6 w( r
hers to follow over the next year. 9 {. T' _, Y( M) h
3 B( W: }& B FThe Radeon HD 5870 is first and foremost a card for gamers, so unless you're b
% r6 m) @: t n$ g+ Y# nuilding a dual-purpose HTPC, this isn't the one you're going to want to use. I
' t" R& W1 i+ L! c$ k2 r5 B* Z9 A- zf you can wait, the smaller derivatives of the RV870 core will also have bitst
' n5 q @$ q1 Nreaming support for TrueHD/DTS-HD MA. If you can't and have a deep enough HTPC4 y9 ~1 |0 a( |: G/ A6 @
case, the 5870 will work.
; R8 y8 j, X9 e+ y1 N0 h0 F% n$ j4 H5 j+ B9 K! S4 w) I
In addition to full bitstreaming support, the 5870 also features ATI's UVD2 (U; }+ ~$ y, l1 X2 F1 _- ]/ I7 ~
niversal Video Decoder). The engine allows for complete hardware offload of al
9 q/ Q/ k. o& G2 ]% t+ F' |, N, Al H.264, MPEG-2 and VC1 decoding. There haven't been many changes to the UVD2
: a! T% j& c9 R/ `) Pengine; you can still run all of the color adjusting post-processing effects a6 O F$ U @5 q: L
nd accelerate a maximum of two 1080p streams at the same time.4 H6 W- ?7 V- j' z# v
! Z1 W8 r$ c( F' v( Q! Q
ATI claims that the GPU now supports Blu-ray playback/acceleration in Aero mod
) N- ^3 E* P u: u [e, but I found that in my testing the UI still defaulted to basic mode.2 }' w$ q3 g- u9 [$ `8 B/ ]" ]3 m
k- x& `$ u8 K( N% B) R* A7 @To take advantage of the 5870's bitstreaming support I had to use a pre-releas# D5 f4 [% z8 j& W2 E X0 t& g
e version of Cyberlink's PowerDVD 9. The public version of the software should
) m& o* M5 E' T1 `. ybe out in another week or so. To enable TrueHD/DTS-HD MA bitstreaming you hav0 q% t E) |6 q9 E2 g$ B0 k
e to select the "Non-decoded high-definition audio to external device" option
1 i& l: D1 B* Jin the audio settings panel:
$ o: k7 Z3 g1 e8 ~+ c; f$ L4 [, w# j& a* W/ S' w. |
With that selected the player won't attempt to decode any audio but rather pas
, m; B& W' c* z- `s the encoded stream over HDMI to your receiver. In this case I had an Integra1 y# S+ n+ Q2 M$ F
DTC-9.8 on the other end of the cable and my first test was Bolt, a DTS-HD MA
4 M- z5 G: B, _/ v1 Btitle. Much to my amazement, it worked on the first try:* L: v3 |+ ~5 X+ T3 u& U1 ?0 y. o# I
! E0 }- k- ] J) M: c# P
No HDPC errors, no strange player issues, nothing - it just worked. # K3 c9 J0 o( @# l# m7 j. E+ f
4 G# `3 ?% ~' uNext up was Dolby TrueHD. I tried American History X first but the best I coul/ J9 d5 \) ^/ y
d 【请注意文明用词】 of it was Dolby Digital. I swapped in Transformers and found the sam9 V4 ~4 V# C0 y6 m; h
e. This ended up being an issue with the early PowerDVD 9 build, similar to is! N' O1 S+ d6 l3 G# E) K
sues with the version of the player needed for the Auzentech HomeTheater HD. S! M0 u4 j" r6 m# H) x- N
witching audio output modes a couple of times seemed to fix the problem, I now
4 Q& @0 h8 Y% Q1 W( S% d7 Zhad both DTS-HD MA and Dolby TrueHD bitstreaming from the Radeon HD 5870 to m. y7 d- Z$ P, o8 r- k! W' Q
y receiver.
, g0 |0 m. d9 [$ [8 u" ?) D8 y2 g5 z: @
' e1 F# |3 B& }3 ~5 zOne strange artifact during my testing was the 5870 apparently delivered 1080i
5 e: n' Q0 e5 w6 loutput to my JVC RS2 projector. I'm not exactly sure what went wrong here as 7 d6 d: {5 E8 k/ R; P
1080p wasn't an issue on any other display I used. I ran out of time before I 7 y# R0 _) W6 t- f4 s' ]% C, i
could figure out the cause of the problem but I expect it's an early compatibi5 T: ~! i3 G6 ]# I! x
lity issue.
5 A: e1 T. K4 [' _) p4 Z: B2 I! ]( ]1 B2 I T
I can't begin to express how relieving it is to finally have GPUs that impleme" a9 |) U% O; U+ ?# |" x
nt a protected audio path capable of handling these overly encrypted audio str
6 @# e5 x# B" Ieams. Within a year everything from high end GPUs to chipsets with integrated
4 G7 o( r# S; f7 h& ~# cgraphics 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