# PCM vs Bitstream



## Wayde

Please help me settle a minor dispute.

A source device which shall go nameless (it's not hi-fi gear, it's a mass produced retail item that sells for about $300) and we'll say hypothetically say it's capable of either bitstream or PCM via its HDMI output to your middle/hi-end hi-fi receiver (which is designed for hi-fi acoustics and retailed for around $2000.)

Which is best for optimal sound (using HDMI output on source to HDMI in on the receiver) 

1/ Set the source to _bitstream _to the receiver and let the receiver's DACs decode any audio codec it encounters.

2/ Set the source to _PCM _and let the source device (not hi-fi) conduct the decoding and the receiver can handle the raw PCM and just play it back to the speakers. 

3/ Set the source's output however you want _bitstream/PCM_ doesn't matter because decoding an audio codec is just like opening a ZIP file anyway, it's all the same. No perceptible acoustic differences will be present. 

Let me know which (if either) of the choices you would agree to and why. 

Thank you for your input.
Wayde


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## bobgpsr

With bitstream it is possible that there will end up being a bit less clock jitter to the Digital to Audio Converters (DACs) in the receiver. This would be due to the packetizing of the audio data with bitstream thereby requiring a independent clock generated in the receiver. Linear PCM via HDMI will use a clock derived from the HDMI video clock for the DACs. Some report that more jitter to the DACs' clock results.

A high end AVR or Pre-Pro may have much more sophisticated DAC clock recovery circuitry for a PCM input (either via HDMI or S/PDIF). Then the difference (hearing DAC clock jitter effects) may be very hard to detect.


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## Toolatecrew

Depends on what the source material is. If its HD Master Adio or other HD coec on a BluRay only having the unamed source component decode it and output PCM will get you ther HD Audio


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## Wayde

Toolatecrew said:


> Depends on what the source material is. If its HD Master Adio or other HD coec on a BluRay only having the unamed source component decode it and output PCM will get you ther HD Audio


I'm not sure that's right. 

I have a BD player and it bitstreams to my AVR (hdmi 1.3) and the receiver decodes DTS HD-MA just fine. If I understand you correctly you're saying that only the source can decode that particular codec.


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## Wayde

bobgpsr said:


> With bitstream it is possible that there will end up being a bit less clock jitter to the Digital to Audio Converters (DACs) in the receiver.


So, if it was your a/v gear you'd bitstream to the receiver?

from what I understand the differences between cheap DACs and expensive brand name DACs (wolfson, Burr-Brown) are large. I never knew about it being the clock but what I understand is that the digital to analog conversion can be performed in a number of ways... some are done cheaply and generically so as not to require much processing power. Others are done in a more sophistocated manner requiring higher powered DACs that consequently cost more.

Or am I buying into audiophile myths?

I would have to believe that a mid-line Denon DVD player will decode Dolby Digital in a far superior maner than a $50 Wal-Mart special (assuming both had analog outs and could perform the decoding internally).


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## bobgpsr

If I had a new HDMI 1.3 AVR with the new codecs and a new display that uses HDMI 1.3 -- then I would use bitstream output on HDMI 1.3 from my HD-XA2 player.

Yes, the quality of the DAC can matter. But it seems that many hi def players are using good quality (mid-range for audiophiles) DACs anyway so that is not a big factor for mid-range audio users. Those who spend more than $10K for a player or Pre-Pro will feel different. But both linear PCM and bitstream use the DACs at the end destination (AVR, receiver, Pre-Pro). The player's DACs only matter if you are using an analog connection (stereo or multi-channel analog).

Just that DACs need to be accurately clocked (triggered to do a sample conversion) at a consistant time interval, centered where the digital sample data has stabilized at the DAC's inputs. It is possible to hear the effects of inconsistant clocking or a clock that is so skewed off in time that the input sample data is not settled but rather is changing to or from another sample set. This is one real electrical engineering technical detail/requirement that I know can be a factor with the sound quality. 

Early CD players outputing linear PCM on a digital S/PDIF (coax or Toslink) connection to the earliest S/PDIF capable receivers had DAC clock jitter issues at the receiver end. Higher end Pre-Pro's reduced this issue with more elaborate PLL clock recovery circuitry.

Sending audio digitized into packets (as bitstream does) for transport via HDMI or IEEE-1394 firewire (iLink) ends up requiring receiver clock circuitry that avoids the "jitter" issue.


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## Toolatecrew

Wayde said:


> I'm not sure that's right.
> 
> I have a BD player and it bitstreams to my AVR (hdmi 1.3) and the receiver decodes DTS HD-MA just fine. If I understand you correctly you're saying that only the source can decode that particular codec.





> A source device which shall go nameless (it's not hi-fi gear, it's a mass produced retail item that sells for about $300)


Only source device I know that fits that discription (in terms of HD Audio) is a PS3. A PS3 will not bitsteam anything other than Dolby Digital. No high def.

I assumed it was a PS3 as I'm not sure why he wouldn't simply give the nodel number of a BR player?


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## Wayde

Toolatecrew said:


> Only source device I know that fits that discription (in terms of HD Audio) is a PS3. A PS3 will not bitsteam anything other than Dolby Digital. No high def.
> 
> I assumed it was a PS3 as I'm not sure why he wouldn't simply give the nodel number of a BR player?


*Good call Toolatecrew!*

You assumed correct, I didn't want to say PS3 because it enters into the realm of fanboyism and I don't care of it's a PS3 or box of Pop Tarts, I just wanted to know which would be 'optimal'.

Since the PS3 is incapable of bitstreaming the hi-res codecs my _contention_ is that a BD player capable of bitstreaming would be a better option for overall sound quality if you're using a higher-mid range AVR that is capable of decoding the bitstream.

No, that's not a knock on the PS3. I'm sure it's a wonderful device that makes a lot of people very happy. 

A lot of people get very touchy about it and I wanted to separate facts from favoritism. 

If the PS3 _were _bitstream capable and you had an AVR capable of decoding the hi-res codecs... which would you do - Bitstream or PCM? 

I doubt anyone that had a choice would do the latter even if the differences were negligible.

As bob points out cheap DACs have come a long way in recent years. So, maybe it wouldn't matter to anything under a true audiophile grade setup.


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## Toolatecrew

Wayde said:


> *Good call Toolatecrew!*
> 
> You assumed correct, I didn't want to say PS3 because it enters into the realm of fanboyism and I don't care of it's a PS3 or box of Pop Tarts, I just wanted to know which would be 'optimal'.
> 
> Since the PS3 is incapable of bitstreaming the hi-res codecs my _contention_ is that a BD player capable of bitstreaming would be a better option for overall sound quality if you're using a higher-mid range AVR that is capable of decoding the bitstream.
> 
> No, that's not a knock on the PS3. I'm sure it's a wonderful device that makes a lot of people very happy.
> 
> A lot of people get very touchy about it and I wanted to separate facts from favoritism.
> 
> If the PS3 _were _bitstream capable and you had an AVR capable of decoding the hi-res codecs... which would you do - Bitstream or PCM?
> 
> I doubt anyone that had a choice would do the latter even if the differences were negligible.
> 
> As bob points out cheap DACs have come a long way in recent years. So, maybe it wouldn't matter to anything under a true audiophile grade setup.


If the PS3 could bitstream I might well let it do so just so I see the little Dolby HD thingy light up on my 3808. It looks cooler than PCM Multi Channel and I can tell if its DTS HD or Dolby HD or whatever without pushing the the button on the PS3 remote. I'm happy to let whatever piece of gear that is software upgradable to accommodate new formats do the decode. 

I do not believe there is any difference in where the HD audio is uncompressed. I subscribe to the zip file analogy. 

We are not talking about analog outs here. Its HDMI vs Toslink or HDMI vs HDMI (in terms of a PS3). You can ONLY get HD over HDMI. 

I'm no fanboy. I have a PS3 and an HD DVD player. I could have spent more $ and gotten an HDDVD player that would bitstream but saw absolutely no reason to. Its just my opinion though. I can't hear a difference and to me that's all that matters. If someone else can hear a difference more power to them .


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## Wayde

I'm with bob... probably 99.9% of people's gear won't hear a diff. But if it's available, I'd rather bitstream.


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## bobgpsr

Just to clarify, remember:

The player's DACs only matter if you are using an analog connection (stereo or multi-channel analog).


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## MatrixDweller

I don't know why DACs would be an issue either. It's a digital source either way passed over a digital cable. It would be the decoder that would come into play. Decode at source or decode at destination is the question. 

I personally can't tell the difference when flipping between bitstream and LPCM for Dolby Digital or DTS on my PS3 to my Denon 4306. The only benefit I can tell is that the display on the 4306 reads Dolby Digital rather than Multi Ch In. 

One area I could see that it would have effect would be if the decoder (source or destination) extrapolates a higher sample rate from lower one (ie: Denon's AL24 processing or the PS3's audio upconversion). In that being if the source could upsample to 192khz and do nice job of it and the destination can't, then bitstream looses out.


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## Moonfly

This is basically how I see it (feel free to correct me people), LPCM has the player decoding the soundtrack from its compressed format on the disc into an uncompressed one that is then sent to a compliant receiver. The receiver then plays the data. Bitstream means the compressed audio on the disc is sent untouched from the disc (via the player) to the receiver, the receiver then uncompressed/decodes the sound and plays it.

Which is the best way?

I'd say this depends entirely on each persons setup. Lets assume a receiver that can decode both formats and a player that can send both formats at all levels of sound (upto true HD etc). If you have a basic receiver then you should let your player decode as it will be a superior decoder (LPCM). If you have very good HT then you should let the AV receiver do the decoding (bitstream) as this will be superior to the players.

As someone has already stated, the PS3 is different as it wont send HD sound as bitstream so for that particular device LPCM is what you need. All stand alone player will send both formats just fine as far as i know.


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## salvasol

Moonfly said:


> If you have a basic receiver then you should let your player decode as it will be a superior decoder (LPCM)...


But is not just any basic receiver, Right??? ... you CAN NOT GET TrueHD or DTS HD through optical or coaxial cable, you need to use the analog multi channel input, Right???


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## MatrixDweller

Yes...exactly...most "Basic" receivers don't have the lossless codec decoders. Unless you consider something like the Onkyo 606 or a Pioneer VSX-1018AH "basic". I would think that the digital bits outputted would be the same no matter what decoded it. They all use the same algorithm after all.


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## salvasol

MatrixDweller said:


> ... Onkyo 606 or a Pioneer VSX-1018AH "basic". I would think that the digital bits outputted would be the same no matter what decoded it. They all use the same algorithm after all.


Those AVR are able to decode TrueHD and DTS HD ... 

How do you connect/use an AVR that can't decode them but your DVD player can??? ... It can't be done through the optical/coaxial cable, Right???


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## MatrixDweller

You need to either use the HDMI connection and the then receiver must support LPCM over HDMI

or 

the player must have 5.1/7.1 analog outputs and the receiver must have 5.1/7.1 analog inputs

You are correct that the lossless audio cannot be passed over optical or coaxial in either encoded or decoded form.


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## salvasol

MatrixDweller said:


> You need to either use the HDMI connection and the then receiver must support LPCM over HDMI
> 
> or
> 
> the player must have 5.1/7.1 analog outputs and the receiver must have 5.1/7.1 analog inputs
> 
> You are correct that the lossless audio cannot be passed over optical or coaxial in either encoded or decoded form.


That's what I thought ... :sad:

I was getting excited ... my RXV 2700 can't decode TrueHD or DTS HD, it has the multichannel inputs but my HD D3 doesn't have the multichannel outputs so I'm using optical/coaxial :doh:


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## tonyvdb

Hi David, dont get too worked up about TrueHD or DTS HD as there is very little noticeable difference between DTS and Dolby digital+ over TrueHD or DTS HD the bitrate numbers may look allot higher but to most people it really is not a huge noticeable difference.


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## salvasol

tonyvdb said:


> Hi David, dont get too worked up about TrueHD or DTS HD as there is very little noticeable difference between DTS and Dolby digital+ over TrueHD or DTS HD the bitrate numbers may look allot higher but to most people it really is not a huge noticeable difference.


Thank you ... :T

Sometimes I think that HT beginners have more fun (is not that I'm an expert but I learned a lot here :bigsmile because they don't know or care about getting the best out of their system :yes: ... until they start learning and start reading ... then they become like me :dizzy: :yes:


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## MatrixDweller

I have noticed some difference between DVD and Bluray versions of movies and their soundtracks. I think DTS HD and Dolby True HD can pack more info into the surround and LFE channels. Plain DD and DTS kind of limited them a bit and they would put most of the information into the front three channels. 

You are still right for the most part though because with many movies though there is little difference. Studies have shown that non-audiophiles can't tell the difference between 128mbps MP3s and lossless audio. So for the most part, unless you are really listening, you may not be able to tell the difference.


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## Moonfly

salvasol said:


> But is not just any basic receiver, Right??? ... you CAN NOT GET TrueHD or DTS HD through optical or coaxial cable, you need to use the analog multi channel input, Right???


You need HDMI for the HD formats, all integrated amps I have seen only have 6 channels via analogue and not all will convert the digital HD source and output via analogue without dropping it to 6 channel. The only time you would use analogue for HD audio is with a separate pre/power amp combination, where the pre amp does the decoding and then has 8 analogue feeds to the power amp/s.


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## Moonfly

MatrixDweller said:


> Yes...exactly...most "Basic" receivers don't have the lossless codec decoders. Unless you consider something like the Onkyo 606 or a Pioneer VSX-1018AH "basic". I would think that the digital bits outputted would be the same no matter what decoded it. They all use the same algorithm after all.


I would put the ps3 on a par with a 606 (not entirely sure what the 606 will and wont decode re HD audio) but I would say a stand alone player would be better. I have an 875 and I would bitstream everything via HDMI unless I had a top spec stand alone (or PS3 obviously), if I had something like the Dolby Lake processor I would bitstream every time without exception.

Better decoders do a better job regardless of the algorithms because they have better cpu's etc, that work faster and dont stutter (for lack of a better word). The differences are not always immediately obvious but if you compared a setup with the 606 as a processor in one and the dolby lake processor in another you would notice the difference.


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## Moonfly

tonyvdb said:


> Hi David, dont get too worked up about TrueHD or DTS HD as there is very little noticeable difference between DTS and Dolby digital+ over TrueHD or DTS HD the bitrate numbers may look allot higher but to most people it really is not a huge noticeable difference.


Sorry but i strongly disagree with this. My xbox doesn't sound anywhere near as good as the PS3, and neither does my stand alone dvd player which in its day was a very good player.

The PS3 sounds marginally better for 5.1 but when 7.2 HD is outputted the 875 just shines.


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## Moonfly

MatrixDweller said:


> I have noticed some difference between DVD and Bluray versions of movies and their soundtracks. I think DTS HD and Dolby True HD can pack more info into the surround and LFE channels. Plain DD and DTS kind of limited them a bit and they would put most of the information into the front three channels.
> 
> You are still right for the most part though because with many movies though there is little difference. Studies have shown that non-audiophiles can't tell the difference between 128mbps MP3s and lossless audio. So for the most part, unless you are really listening, you may not be able to tell the difference.


The DVD and BR soundtracks are stored digitally, so the original soundtrack, after being composed in the studio is converted by computer into nothing more than digital information. The more space you have to store the information the less of it gets lost in translation.

HD sound formats allow greater separation of the channels/frequencies within the recording so they dont contaminate each other, more channels equals more clarity. This isnt alway immediately noticeable as its not so much the quality of the audio thats the difference, its how you can pick out different subtle sounds and notes and how they are clearer.

Of course you do need the rest of your audio setup to be of a good enough level to reproduce this. An example of this is MP3's. On an personal mp3 player they sound as good any a normal recording, but when I play an mp3 file through my 875 I cant stand it. Many a time I have put something new on and thought, that sounds awful, I check the file format and low and behold its an mp3. I can pick an MP3 out blind every time on my HT kit, but never on a personal mp3 player.

FYI, MP3 is a compression technique that removes frequencies that personal music players are incapable of reproducing. The music player cant reproduce them so you dont miss them and the compression saves storage space. Its only on proper kit you start to realize somethings missing, and then only when you have something to compare it too. Same when comparing DD/DTS and DTS MA/True HD.

DTS does sound very good though and I'm not trying to put the format down, but HD is better.


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## ndurantz

MatrixDweller said:


> You need to either use the HDMI connection and the then receiver must support LPCM over HDMI
> 
> or
> 
> the player must have 5.1/7.1 analog outputs and the receiver must have 5.1/7.1 analog inputs
> 
> You are correct that the lossless audio cannot be passed over optical or coaxial in either encoded or decoded form.


Trying to get my arms around this :scratchhead: So for me, I am looking at getting a Samsung BD-UP5000, which has 7.1 analog outs and an Onkyo receiver that has 7.1 analog ins. The receiver only passes video with the HDMI. Would I use LPCM or Bitstream? Thanks!


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## MatrixDweller

Moonfly said:


> Of course you do need the rest of your audio setup to be of a good enough level to reproduce this. An example of this is MP3's. On an personal mp3 player they sound as good any a normal recording, but when I play an mp3 file through my 875 I cant stand it. Many a time I have put something new on and thought, that sounds awful, I check the file format and low and behold its an mp3. I can pick an MP3 out blind every time on my HT kit, but never on a personal mp3 player.


I hear you on this big time. Sometimes a good variable bitrate at 128mbps sounds "OK" but I typically find anything under 192kbps sounds terrible. I should add that an untrained ear doesn't necessarily pick out the MP3 artifacts. My wife has a CD of songs that she burned from a MP3 source and she thinks it sounds pretty good whereas I can hear the tinny compression sound and weak bottom end on all of the tracks. And that's when it's playing on my factory Chrysler stereo in my Minivan.

Your entire post was very well written moonfly :T.


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## MatrixDweller

ndurantz said:


> Trying to get my arms around this :scratchhead: So for me, I am looking at getting a Samsung BD-UP5000, which has 7.1 analog outs and an Onkyo receiver that has 7.1 analog ins. The receiver only passes video with the HDMI. Would I use LPCM or Bitstream? Thanks!


It probably doesn't matter in that case so long as the analog outputs work. What receiver model is it? The TX-SR606 will give you HDMI 1.3 with HD decoders for under $400.


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## ndurantz

MatrixDweller said:


> It probably doesn't matter in that case so long as the analog outputs work. What receiver model is it? The TX-SR606 will give you HDMI 1.3 with HD decoders for under $400.


Yeah. I pulled the trigger right before all the receivers started integrating the audio of the HDMI. I bought the Onkyo HT-800, which included the HTR 550. I can't hyperlink this 'cause I am a newbie - onkyousa.com/model.cfm?m=HT-SR800&class=Systems&p=i

The analog inputs are there. It does all decoding up to the HD codecs. Additional thoughts?


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## DougMac

Wayde said:


> *Since the PS3 is incapable of bitstreaming the hi-res codecs* my _contention_ is that a BD player capable of bitstreaming would be a better option for overall sound quality if you're using a higher-mid range AVR that is capable of decoding the bitstream.


I have a question. Is this PS3 limitation hardware or software related? If it's the former, we're SOL. The latter would leave room for possible upgrading. I know that some features have been added this way.

I'm definately not a fanboy, but one of the reasons I bought a PS3 was the ability for software upgrades to help keep up with changing standards.

I'm fairly new to BD and the PS3. I went to show the grandkids "The Waterhorse" Saturday night and it wouldn't play until I upgraded! I had not connected the PS3 to my wireless network, so that was Step 1. The whole process was easy, but since the download was so large, it would be too late to start the movie. We watched Buster Keaton instead. The upgrade was successful and we watched "The Waterhorse", sans rug rats Sunday night.

Doug


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## atledreier

I may be off topic here, but I'll ask anyway.

If the hi-res sound formats are lossless, does it matter what unit decodes it? HDMI 1.3 do some sort of jitter suppression, and a lossless bitstream or a LPCM datastream should come out exactly the same in 'the other end', shouldn't it? 

I use a PS3 currently, and the hires stuff sounds fine to me. Sure, I don't get the fancy DTS-MA logo in my processor's display, but I can press 'SELECT' on my PS3 and display it, and it's still the same soundtrack. I just don't see the big deal with bitstreaming, honestly.


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## salvasol

atledreier said:


> If the hi-res sound formats are lossless, does it matter what unit decodes it? HDMI 1.3 do some sort of jitter suppression, and a lossless bitstream or a LPCM datastream should come out exactly the same in 'the other end', shouldn't it?


I don't have any HD equipment ... but I read that it can be decoded by source (player) or AVR :yes:

The question I think it is: Which one does a better job??? ... and that's the resaon some use bitstream and other LPCM ... but I could be wrong :bigsmile:


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## Moonfly

ndurantz said:


> Trying to get my arms around this :scratchhead: So for me, I am looking at getting a Samsung BD-UP5000, which has 7.1 analog outs and an Onkyo receiver that has 7.1 analog ins. The receiver only passes video with the HDMI. Would I use LPCM or Bitstream? Thanks!


LPCM, chances are your player will set to this itself anyway to play via analogue. The source material will be decoded in player, then sent as uncompressed data to your amp. Your amp will simply receive the decoded signal and reproduce it.
Analogue connections are more for just sending the sound, digital connections are the ones that tend to handle data, i.e un-decoded soundtrack information.


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## Moonfly

atledreier said:


> I may be off topic here, but I'll ask anyway.
> 
> If the hi-res sound formats are lossless, does it matter what unit decodes it? HDMI 1.3 do some sort of jitter suppression, and a lossless bitstream or a LPCM datastream should come out exactly the same in 'the other end', shouldn't it?
> 
> I use a PS3 currently, and the hires stuff sounds fine to me. Sure, I don't get the fancy DTS-MA logo in my processor's display, but I can press 'SELECT' on my PS3 and display it, and it's still the same soundtrack. I just don't see the big deal with bitstreaming, honestly.


In theory it makes no difference at all. Where the difference is, is in the equipment used to decode. Its more a question of which of my equipment is better, not which method is better. For most of us it really wont make any difference, but for some it might. More at the real professional end really though, or those like me who like to pretend they are in that league lol.


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## atledreier

But if the audio is encoded in a lossless format, then it shouldn't matter where it is decoded, the exact bit for bit stream should come out the other end no matter what. I don't see where there's any room to do it good or bad. Lossless is bitperfect no matter who decode it.


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## Moonfly

atledreier said:


> But if the audio is encoded in a lossless format, then it shouldn't matter where it is decoded, the exact bit for bit stream should come out the other end no matter what. I don't see where there's any room to do it good or bad. Lossless is bitperfect no matter who decode it.


The decoding is the easy bit. Its what it then does with the decoded material and how it uses it. What sound is sent where and how well. A decoder doesn't just decode, it then uses the information to replay the soundtrack and again it starts to boils down to a lost in translation factor, what sounds get sent where and how well makes a difference, and processors like the Dolby lake processor give you infinitely more option to augment the sound than something like an all in one system or a ps3. 

LPCM is more for decoding where a setup has few options to decode the source material. Also the total computing power of a device is always a limiting factor, in theory (yet again) its better to have any 1 device doing as little as possible and sharing the total load, although you could just as easily argue that this is what these devices are designed to do so it shouldn't be a problem anyway.


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## atledreier

Still.. If you decode the lossless stream in the player and then ship it to the processor, or if the processor decode the stream and further process it shouldn't matter as long as you have a bit perfect stream. That is my point. Only difference is your processor's display will say 'multichannel input' instead of the far more sexy 'DTS-HD Master'.


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## Moonfly

There are those that agree with you and those that wont, its a hot topic these days and I can see where your coming from. The example I have from experience is between a Bose lifestyle system (£2300 new so should be a very good processor) and my Onkyo 875. Both using my Panasonic RV-60 dvd player ( a very good player in its day). This DVD player has onboard decoding and can send 5.1DD via PCM or bitstream. The Bose couldn't decode bitstreams and so used the DVD's decoder and received the sound track via PCM. The Onkyo 875 I now have can decode bitstreams.
The difference is quite noticeable and the 875 places sounds so much better and the feeling or being surrounded by sound is much more complete. You could argue this is as much to do with speakers and amplification but I dont think it is, I would compare the Bose speakers equally with the Kef 2005's I used when I first got surround up and running on the 875.

I think the 875 just does a much better job at decoding the soundtrack than the DVD player itself. DD is stored digitally just like HD soundtracks, and ignoring the quality of the sound between the formats for the minute they should work and decode in the same way with no difference in the spacial sound. I dont believe anything is being lost with either method, just that the 875 is better at decoding. Until I do a proper test with HD formats I can't say the same applies for certain, but I see no reason why it shouldn't be the case. My test is still between two decoding methods from the same source, and so should be a fair test.both sent via digital coax


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## salvasol

Moonfly said:


> The example I have from experience is between a *Bose lifestyle system *(£2300 new so should be a very good processor) and my *Onkyo 875*. Both using my *Panasonic RV-60 *dvd player ( a very good player in its day). This DVD player has onboard decoding and can send 5.1DD via PCM or bitstream. The Bose couldn't decode bitstreams and so used the DVD's decoder and received the sound track via PCM. The Onkyo 875 I now have can decode bitstreams.


I'm not going to argue with you ... but to me is not a fair comparison :duck: addle: :bigsmile:

To start, Blose and Onkyo can compare (according to what I read, Onkyo is a lot, lot better :yes:

To really compare, I suggest you to first decode at the source (Panasonic???) and send that signal to Onkyo ... then let the Onkyo decode the same signal, you will see if there's a difference in the sound or not :yes:

To me, this will be a better test because you'll be using the same source and receiver ... :bigsmile:


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## atledreier

I second that. I was halfway through typing an answer when I realized Salvasol had answered. The Bose will mess it up after decoding no matter how flawless the decoding is. The true test is using the same processor, just different source for the LPCM stream.


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## Moonfly

salvasol said:


> I'm not going to argue with you ... but to me is not a fair comparison :duck: addle: :bigsmile:
> 
> To start, Blose and Onkyo can compare (according to what I read, Onkyo is a lot, lot better :yes:
> 
> To really compare, I suggest you to first decode at the source (Panasonic???) and send that signal to Onkyo ... then let the Onkyo decode the same signal, you will see if there's a difference in the sound or not :yes:
> 
> To me, this will be a better test because you'll be using the same source and receiver ... :bigsmile:


I was expecting that rebut, but here's the thing, the Bose wasnt decoding anything the DVD player was doing it all. Ive also tried the Onkyo in PCM and it was still alot better than the Bose. The thing is there shouldn't be any difference between the Bose and Onky when both are in PCM if the source decoder is all that matters. I cant tell a whole lot of difference on the Onkyo in the 2 different decoding types, but that could be put down to Onkyo doing what Onkyo does. To me this only serves to strengthen the argument that there is a difference between two different decoding devices. The Onkyo is obviously better than both my DVD player and the Bose, which doesnt actually process anything, I previously had when it comes down to processing.

Again I would stress that I cant speak from experience on the HD front, but to myself I have proved that different decoders have different results from the same digital source. In my test I put it down to the fact the Onkyo is better than the Panasonic DVD player and dont think the Bose really had a lot to do with anything, (for the price it was an extremely featureless piece of kit, which is another bad mark against Bose). When I finally get a capable stand alone BR player I'll give it another shot to see if I can reproduce the differences, but I dont think I will using just the Onkyo, I would need another processor.


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## salvasol

Moonfly said:


> I was expecting that rebut, ...


Aha ... :boxer: . :surrender: . :bigsmile:



> but here's the thing, the *Bose wasnt decoding *anything the DVD player was doing it all. Ive also tried the *Onkyo in PCM *and it was still alot better than the Bose. The thing is there shouldn't be any difference between the Bose and Onky when both are in PCM if *the source decoder is all that matters*....


That is true ... but remember that Blose and Onkyo are different; and they will sound different (even if you use the same speakers with both). By the way; Were you using the same speakers when you did the test???



> ... that different decoders have different results from the same digital source. In my test I put it down to the fact the Onkyo is better than the Panasonic DVD player and dont think the Bose really had a lot to do with anything, ...


That was the original question ... and most agree that you have to use the equipment that does a better job (as you discovered, your Onkyo is better than the player).



> ... When I finally get a capable stand alone BR player I'll give it another shot to see if I can reproduce the differences, but I dont think I will using just the Onkyo, I would need another processor.


Why you'll need another processor??? ... I think you just have to compare who does a better job decoding: BR player or Onkyo, and use the one who decodes better :yes:


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## MatrixDweller

Moonfly said:


> the DVD player was doing it all


I have noticed that the onboard decoders in older DVD players are not necessarily as good as the ones in the good receivers. I had a Samsung HD841 which did a terrible job of it. The chipset was just cheap and was subject to jitter (or is it judder?) from a cheap clock crystal.

I think we are more referring to modern Bluray players and of which I haven't been able to discern an audible difference.


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## Moonfly

MatrixDweller said:


> I have noticed that the onboard decoders in older DVD players are not necessarily as good as the ones in the good receivers. I had a Samsung HD841 which did a terrible job of it. The chipset was just cheap and was subject to jitter (or is it judder?) from a cheap clock crystal.
> 
> I think we are more referring to modern Bluray players and of which I haven't been able to discern an audible difference.


But this would seem to prove that different decoders produce different results from a single digital source, which is the question being posed here. FYI, the DVD player I have was considered one of the best in its class in its day so should be fairly good.


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## Moonfly

salvasol said:


> Aha ... :boxer: . :surrender: . :bigsmile:
> 
> 
> 
> That is true ... but remember that Blose and Onkyo are different; and they will sound different (even if you use the same speakers with both). By the way; Were you using the same speakers when you did the test???
> *The speakers in each test were different, they were Bose and Kef 2005. I no longer have the kefs as I gave them to my brother. I now only have 2.1 till I get my fronts upgraded and shift them to the back.*
> 
> 
> That was the original question ... and most agree that you have to use the equipment that does a better job (as you discovered, your Onkyo is better than the player).*So different processors do give different results, even though the source is digital and compressed with identical codecs?*
> 
> 
> 
> Why you'll need another processor??? ... I think you just have to compare who does a better job decoding: BR player or Onkyo, and use the one who decodes better :yes:*I think it would be more of a fair test, but your right, it should be enough with a player and the 875.*


When I finally get everything sorted and give it another try, its a good excuse to play around :bigsmile::yay:


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## gorji

This is a great discussion. Please keep it going and educate us interested in this area of signal processing.


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## Moonfly

Ive done a bit of reading about here and there and ive noticed that as signal processors get progressively more expensive they tend to give more olptions in the tweaking department. Something like the Dolby Lake processor gives you many mor parameters to adjust than something like your average avr. You get the same step down when using players inbuilt decoders. I think it may be a case that in the end, the results produced will sound better via a better processor because you can tailor the sound to your specific environment better rather than any actual difference in the quality if th sound.

I think in the end this is probably where the perceived improvement comes from, but an improvment it is. I still say different processors give differing results.

Now, as to whether runing in PCM or Bitstream is preferable on any one given processor I cant really tell the difference but I would choose to let my AVR process the compressed information over a players inbuilt processing as long as my AVR/processor was of a suitable quality.


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## redduck21502

My receiver doesn't decode TrueHD nor DTS-HD MA, but my Sony BDP-S550 that I have coming soon does. I have to send the decoded HD audio via LPCM over HDMI for those movies. My question would be, if a blu-ray movie had one of the HD encodings and PCM 5.1 (48kHz, 16-bit) on the same disc, which would be better to use? I have read that the PCM 5.1 is better than DD 5.1, but I don't know about the HD audio, especially since my player will not decode them. Based on recent comments in this thread, I would say that the TrueHD would be better than the PCM 5.1, but just want to know how to get the best sound.


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## MatrixDweller

Typically you won't find both on a disc but if you do then the end result should be about the same (a lossless audio stream). Any difference would be due to the studio's mixing. Neither DTS HD, DOlby True HD or Lossless PCM holds and real advantage sonically.


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## riehmc

I have a Denon AVR-1610 and Samsung Blu-ray BD-P1600. I have turned off dynamic compression and PCM downsampling on the samsung, but I was wondering if I should use the PCM or Bitstream(audiophile) option. I have everything connected via HDMI and am looking for the best sound. What settings will give me the best sound?

I found this on another site:
http://forums.cnet.com/5208-13973_102-0.html?threadID=341929

Player settings
================

Digital Output, via optical for none HDMI amps:
------------------------------------------------
PCM - (poor)Not really worth using as you can loose multichannel output, but great if you are using a HDMI equipped amp.

Digital (re-encode) - (good) This will re-encode the source audio to a DTS stream always. Even if the source is Dolby Digital (DD) 5.1

*Digital (audiphile) - (best) Pipes the audio source to the amp.

I found out that I can use the audiophile setting and any DTS-HD, Dolby TrueHD etc comes through fine! How my amp copes with these I'm not sure, but it could be because the formats are backwards compatible?


PCM Down sampling:
------------------
On - output is @ 48Khz
*Off - output is @ 96Khz (if source audio supports it otherwise 48Khz)

I have this turned off as my amp can cope with that rate.


Dynamic Range Compression:
---------------------------
Off - quiet speech will be quiet and loud noises very loud. Can lead to turning up and down the volume on the amp during watching the film.

*On - Pulls the quiet parts of the film up a bit so less volume twiddling.

Note your amp may support this to, sometimes it is called "Night mode". If you have it turned on in your amp, turn it off here.


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## redduck21502

riehmc said:


> I have a Denon AVR-1610 and Samsung Blu-ray BD-P1600. I have turned off dynamic compression and PCM downsampling on the samsung, but I was wondering if I should use the PCM or Bitstream(audiophile) option. I have everything connected via HDMI and am looking for the best sound. What settings will give me the best sound?
> 
> I found this on another site:
> http://forums.cnet.com/5208-13973_102-0.html?threadID=341929
> 
> Player settings
> ================
> 
> Digital Output, via optical for none HDMI amps:
> ------------------------------------------------
> PCM - (poor)Not really worth using as you can loose multichannel output, but great if you are using a HDMI equipped amp.
> 
> Digital (re-encode) - (good) This will re-encode the source audio to a DTS stream always. Even if the source is Dolby Digital (DD) 5.1
> 
> *Digital (audiphile) - (best) Pipes the audio source to the amp.
> 
> I found out that I can use the audiophile setting and any DTS-HD, Dolby TrueHD etc comes through fine! How my amp copes with these I'm not sure, but it could be because the formats are backwards compatible?
> 
> 
> PCM Down sampling:
> ------------------
> On - output is @ 48Khz
> *Off - output is @ 96Khz (if source audio supports it otherwise 48Khz)
> 
> I have this turned off as my amp can cope with that rate.
> 
> 
> Dynamic Range Compression:
> ---------------------------
> Off - quiet speech will be quiet and loud noises very loud. Can lead to turning up and down the volume on the amp during watching the film.
> 
> *On - Pulls the quiet parts of the film up a bit so less volume twiddling.
> 
> Note your amp may support this to, sometimes it is called "Night mode". If you have it turned on in your amp, turn it off here.



I know you left the post because you couldn't delete it, but I am going to respond anyway.

I just read Home Theater magazine this month and remember a similar topic on AVRs. Here is a quote:
"If the receiver can receive a high resolution PCM signal via HDMI, it doesn't need onboard lossless decodingif the player it's connected to does. In fact, it's arguably better to decode these formats in the player because in the AVR prevents you from hearing the so-called 'secondary audio' such as the audio from commentaries or Bonus View PIP windows that you access during the main Blu-ray program." - _Home Theater_ August 2009 Volume 16 No. 8


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## riehmc

I noticed this as well, that's why it has been difficult to get a good answer.


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