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Bitstream audio from pc to amp

itsmynewname

Active Member
Hi all i have vista home premium and want to bitstream my mkv files straight to the amp for decoding via hdmi from my asus 5770, my question is which media player and codecs should i use in order to get dts etc straight to the amp, a denon 1909.
Also is it possible to bitstream true hd without having windows 7 as someone has suggested that i cannot bitstream true hd unless i have windows 7 whereas i thought i would be fine once i had my 5770 card?
 

itsmynewname

Active Member
Just been having a look on google and was wondering if i get power dvd and play my mkv files will they automatically be bitstreamed to the amp?
 

jameson_uk

Well-known Member
You need Win7 to bitstream HD audio with an ATI 5xxx card.

Not sure what PowerDVD is like with MKV files even on Win7 there stands a good chance it won't bitstream anyway. I believe the latest update to TMT has fixed this so that will now bitstream from files but again that is Win7 only with an ATI 5xxx card.

On Vista your only options for HD Audio are decode it and output as LPCM over HDMI or via analogue. PowerDVD and TMT etc should handle this from disc but they do vary in how they handle files. Trying to do this in a player like MediaCetre, Mediaportal etc is a bit more of an issue as you need to use FFDShow to do the decoding and it can not handle DTS-HD (will only output this as standard DTS). There is also the slight issue that if decoding then all commercial players will re-sample the output to 16bit 48Khz which means you could loose a bit of quality over bitstreaming but at that level the difference over ac3/dts is massive anyway and the difference between re-sampled LPCM and a bitstream far less
 

itsmynewname

Active Member
I did have windows 7 on but dont think my motherboard supports it as it kept freezing so i re installed vista. Tbh i dont mind if i can only pass thru dts etc not too bothered about hd and i found this info
ATI Radeon HD 5000 Series Blu-ray HD Audio Bitstream Guide Getting bitstreaming working – the steps required! :: TweakTown
so do i just need the drivers in from catalyst centre to pass thru dts etc using something like mpc? Or do i still need extra codecs like ffd or do they actually decode it first? Would prefer to have my amp decode it just purely so i can see what audio it is rather than seeing it say multi channel in etc.
 

jameson_uk

Well-known Member
do i just need the drivers in from catalyst centre to pass thru dts etc using something like mpc? Or do i still need extra codecs like ffd or do they actually decode it first?
If you only want DD/DTS all you should need to do is set the output in your player of choice to SPDIF and the rest should take care of itself.

Would prefer to have my amp decode it just purely so i can see what audio it is rather than seeing it say multi channel in etc.
Multi-channel though is much better audio quality than a DD/DTS bitstream though...
 

itsmynewname

Active Member
Never realised multi channel is better than dts etc , how is that? Is there a guide that can tell me the differences so i dont have to keep asking questions and troubling people? Thanks by the way for the help so far.
 

jameson_uk

Well-known Member
Never realised multi channel is better than dts etc , how is that? Is there a guide that can tell me the differences so i dont have to keep asking questions and troubling people? Thanks by the way for the help so far.
Guide in my sig ;)

Without DRM then TrueHD / DTS-HD decoded to LPCM is just the same as a zip file being unzipped. With DRM the only real difference is that the audio is resampled to 16bit / 48Khz (which is what a lot of HD audio is encoded at anyway).

Therefore even with the re-sampling you are getting a much higher bitrate than you can get in a DD/DTS stream.

So it is not multi-channel that is better than DTS (you could just decode the DTS to multi-channel and it would be the same as DTS). It is the HD Audio decoded to LPCM and then tansmitted over a multi-channel HDMI connection that is better than DD/DTS :smashin:
 

MikeK

Well-known Member
How much better HD audio is on Bluray over "legacy" codecs, is a very controversial topic amongst people interested in such things ;)


Of course, the companies marketing these new HD audio codecs and those marketing the associated eqpt, would have us believe that the difference is like night and day!
My personal experience is that the difference/improvement is there, but it's often fairly subtle - I certainly don't hear the huge overall improvements others seem to.
(btw - I'm talking about full bitrate lossy codecs, not what you typically get on DVD or via Sky etc)

However, there are many variables at work - nobody else can listen through my ears, or with my eqpt, or in my room, so it's very much a personal thing!


As ever in such things though, placebo effect is ever present- we often hear what we want/expect to hear. It's so easy to be tricked - it is, after all, the basis of how all the lossy codecs work, and why blind testing methods are are always used in any study (not just audio testing), where preconceptual bias might be a problem (eg which cola tastes best?)

People can test this for themselves at home though - in a general sort of way. Try encoding a favorite high quality stereo audio track into various compression codecs - eg DD, MP3, DTS, AAC, OggVorbis, WMA etc, all at highish bitrates - can you tell the difference, and which is best? (as in tasting cola, different doesn't necessarily mean better).
And can you tell which one is best when you don't know which is which beforehand? ;)


BTW - I've never heard a HD audio track sound worse than a "legacy" one, so there is the school of thought which says just pick the HD track, if you can, and be done with it - it's as good as it gets anyway!
Of course, the question then is, if you can't currently pick the HD audio track, is it worth the expense of buying new eqpt so you can?
 

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