Bitstream vs. PCM

[majorloser]

My name is Lenin,... and recently I have realized my BD/ DVD player is able to output bitstream or PCM audio signals? What selection do you recommed to get the best sound quality in stereo & 7.1 multichannel? Why? My receiver is able to take both...via HDMI or optical digital...

Appreciate any help you can provide...

Regards

If your receiver can handle Dolby TrueHD or DTS-HD then you should output PCM through the HDMI cable to the receiver.

 

[wanjeyin]

OK, here's a wrench to throw into the mix. My question is related to the original post, but has to do with the different bitstreams when it comes to high-res audio.

From what I've read, 24/96 PCM cannot be passed over either coax or optical digital audio connections as both use s/pdif and the bandwidth requirements of 24/96 exceed the capabilities of s/pdif.

Does this also hold true for DTS audio discs? I believe they are recorded in 24/96. Might it be because the 24/96 DTS bitstream is compressed the optical/coax connection IS able to carry this particular signal?

Thanks!

AJW

 

[MDS]

Does this also hold true for DTS audio discs? I believe they are recorded in 24/96. Might it be because the 24/96 DTS bitstream is compressed the optical/coax connection IS able to carry this particular signal?

Exactly. DTS 24/96 is actually a compressed format and therefore does not require the bitrate of uncompressed 24/96.

 

[wanjeyin]

Arrrrrgh!!!! When I bought the OPPO 980H I thought it would be the simplest thing to use. What OPPO doesn't tell you in the manual are all the other really advanced settings and conditions to optimize audio according to the type of media used. I'm not saying that the OPPO is a bad player at all, in fact I think it's one of the best out there. It's just a little confusing.

That said, I want to have the whole configuration thing straightened out. I'm sure others will benefit from my frustration.....

From what I've been reading in this forum, and countless others out there, are the following true for the OPPO 980HD, that is, for those WITHOUT HDMI inputs in the receiver? Please correct me where I'm wrong.

1) The 980HD may send any combination of 48, 96, or 192 kHz of signals over optical/coax, however, will be truncated to 16 bits because of the bandwidth limitations.

2) The 96/24 limitations of optical/coax applies only to UNCOMPRESSED bitstream data. 96/24 may still be sent over, however must be compressed as a DTS bitstream.

3) For 5.1/6.1/7.1 Dolby Digital and/or DTS for movie soundtracks, make sure "HDMI Audio" is set to "OFF" and "Digital Output" is set to "Raw". The compressed bitstream will sent directly to your receiver where it will be decoded.

4) I'm not sure about this one, but for DVD-Audio 96/24 stereo outputted over optical/COAX, I'm pretty sure that "HDMI Audio" needs to be set to "OFF". But for output over optical/COAX, is the "Digital Output" set to "RAW" or "PCM"? Does it matter if the "LPCM Rate" set to "48, 96, or 192 k", with respect to whether the "Digital Output" is set to "RAW" or "PCM" mode?

I realize that the 980HD truncates the 24bit bitstream to 16 bits then sends this signal to your receiver.

5) For DVD-Audio 96/24 stereo outputted over analogue, the "Down mix mode" should be set to "stereo" and the "front speaker" set to "large" for DISCRETE two-channel analogue audio with the least amount of conversions in the 980HD. If, in the "DOwn mix mode", "5.1 or 7.1" channels is selected, and the "front speaker" set to "small", the two-channel audio stream is decoded in the player and audio signals under 80 Hz sent to the receiver as a ".1" channel.

6) For stereo or multichannel 96/24 DTS audio, the compressed DTS bitstream will be sent directly to your receiver via optical/coax, where it will be decoded, as long as the "HDMI Audio" is set to "OFF" and "Digital Output" is set to "Raw".

7) For stereo or multichannel SACD audio, the DSD is converted to 24-bit/88.2kHz PCM internally then converted again to analogue internally before it is sent out to your receiver as an analogue signal.

Sorry for the long post, but I've been scratching my head with all the conflicting posts. As such, I really really want to get this whole mess straightened out so that I can optimize my listening experience with the 980HD.

Thanks all!

AJW

 

[RLH]

PCM and Bitstream issue

Will a blu-ray movie encoded in English pcm 7.1 be decoded better in Linear PCM mode or Bitstream?

I know this may be off the subject a little (My AVR will decode PCM Multichannel). Ive noticed that I lose some sound when going to bitstream. That seems a little odd to me as I thought bitstream was basically spitting out exactly what was coming from the blu-ray, DVD, etc... This may have to do with the blu-ray being encoded in PCM 7.1 but I dont know. Does anybody have clue? Are PCM 7.1 encoded items the acception to PCM output being 2 channel, or should I stick with bitstream. (When I say loosing sounds, it is primarily the sound effects of the menu, not the feature)

 

[MatthewB.]

RHL, the reason you are losing the menu sound and not the movie sound, is they are encoded with different codecs. Most menu sound is in two channel stereo or Dolby Digital and thus not being processed by PCM or Bitstream, unless you go into the setup audio menu in the player and indicate that DD and DTS be ouput as PCM, and then you will get your menu sound back.

Also you cannot use the PIP features with Bluray because the reciever will not be able to distinguish between PCM or Bitstream and DD (which the PIP feature uses) at the same time.

 

[bbianca1982]

Along these same lines...

I have the Samsung 1500 BD player and recently bought the Onkyo HT-S5100 home theater in a box. Its a decent system, but I'm having issues determining the best audio setup. I set the BD player's audio output to bitstream from the default PCM (it's running through an optical cable cause the Onkyo AVR only has HDMI passthrough), yet the manual suggests keeping it on PCM if I want to enjoy discs with Dolby TrueHD and DTS-HD (which my AVR can't process).

Bitstream sounds better on the standard Dolby Digital and DTS, but on discs with TrueHD or uncompressed 7.1 PCM (3:10 to Yuma comes to mind) I have no idea what the best setting is.

So, I'd appreciate any pointers anyone here can give me.

 

[TLS Guy]

MDS.... No. The Yammie will not switch to digital modes while in Pure Direct or Multi-channel.

MACCA350... what then is the purpose of PCM? Digital stereo only?

PCM is there for loss less two channel. Lossy codecs such as Dolby digital AC3 do a lousy job of reproducing opera for instance. Almost all opera DVDs have a true CD quality uncompressed PCM track as well. I think almost all opera lovers use the PCM track.

 

[Tomorrow]

Man, I can't believe this thread got resurrected after 2 and a half years.

Hahaaaa, I probably don't understand the format intracacies much better today than I did then. It sucks being old ... and slow. I at least now know how to plug it in and set it up so that it works. Don't confuse me with the facts.

 

[Jack Hammer]

Legit questions, anyone notice this thread started 2 1/2 years ago?

Jack

 

[Alex2507]

Legit questions, anyone notice this thread started 2 1/2 years ago?

Jack

I sure did. As Mtry would say, has the information expired?

Hey Tomorrow,

I don't get it either. All I know is that if my cable box is putting out PCM, I'm pissed. I have to unplug the thing to reset it so that I can get Dolby Digital which I thought was better due to better channel separation spec's listed in my rec'r manual and I thought surround was better with AC3.

Not that I have taken the time to actually compare but that's what I thought I understood. Shoot, now I think I may have mixed up my threads.

Screw it, it's early and I'm just gonna go with it.

 

[MatthewB.]

Actualy PCM can now transmit lossless multichannel surround and not just stereo anymore. I had my HD-DVD and Bluray player set up to pass PCM (both via analog and HDMI) and got the new lossless codecs decoded by the player then sent either way. Now I have and Sony 350 Bluray player which does bitstream via HDMI, HD-DVD A3 which does PCM via bitstream in my bedroom system. And in the Main HT, have my HD-DVD A2 doing PCM via HDMI and PS3 doing PCM lossless via HDMI to my Onkyo 805.

So know for a fact that PCM can be passed either way. I will admit that bitstream decoded by the Denon for me at least did a slightly better job than PCM, although there shouldnt be a difference, my Denon did do a better job. But either way they sound real good.

 

[TLS Guy]

Actualy PCM can now transmit lossless multichannel surround and not just stereo anymore. I had my HD-DVD and Bluray player set up to pass PCM (both via analog and HDMI) and got the new lossless codecs decoded by the player then sent either way. Now I have and Sony 350 Bluray player which does bitstream via HDMI, HD-DVD A3 which does PCM via bitstream in my bedroom system. And in the Main HT, have my HD-DVD A2 doing PCM via HDMI and PS3 doing PCM lossless via HDMI to my Onkyo 805.

So know for a fact that PCM can be passed either way. I will admit that bitstream decoded by the Denon for me at least did a slightly better job than PCM, although there shouldnt be a difference, my Denon did do a better job. But either way they sound real good.

I know, but the multichannel on DVD is lossy. You need the new lossless codecs to avoid the problems I mentioned. The two channel PCM track of a DVD, is the only way to get loss less audio from a standard DVD that I know of.

 

[MatthewB.]

Sorry TLS, i was just thinking of the new HD discs and not of standard DVD, sorry for the confusion on my part.

EDIT also my previous post said PCM by Bitstream, that is a mistype, meant to say PCM by HDMI (but this site times out and won't let me re-edit my post at a later time.

 

[cavaleri]

This is an interesting thread.. I have just purchased my first Blu Ray player, a Samsung BD-P2550 specifically because it has 7.1 analog outputs, which I would need for any 7.1 movies (however few exist) to pass to my older Marantz SR9300 receiver which has 7.1 analog inputs. The receiver is a fantastic receiver that cost 3 grand back in 03, but it doesn't decode any of the newer DTS, trueHD, etc., formats. I have a few questions that I wonder if anyone can help with:

First, What is the best way to set the Player to send audio, given that my reciever does not support the latest formats, but does support THX, THX-EX, and THX-Ultra2. The latter two can take a THX track and matrix the 5.1 into my 7.1 surround back channels. This is nice, because there are many THX films out there that I can receive the benefit of a full 7.1 sound stage. Regarding the newer formats, I'm confused what to send to my receiver. I have tried sending both PCM and Bitstream from the player, and bitstream appears to sound better, although I don't know what mode to set my receiver to. I would have thought that PCM would be better, but don't know what my receiver is attempting to do with the 2 channel format. Any thoughts?

Regarding the 7.1 analog inputs.... I currently don't have any specific 7.1 films (i.e Hairspray, etc.). Moreover, the Samsung BD-P2550 does not currently decode the DTS-HD-MA format, although a firmware update is expected but I digress..). Assuming the player will eventually decode this format, I'm confused on what to send from the player (PCM or Bitstream). I am thinking here that I need to send PCM, since the player will need to do the work to decode the format. It seems obvious that the reciever isn't going to do anything, otherwise why would it supply 7.1 individual inputs. . I also don't know what mode to set the Marantz to either.. Should I set it to something basic like Stereo? Dolby II? THX? Any advice would be greatly appreciated.!!!

 

[sahihai]

Similar situation here...would love to know what is the best set up for a BD Player (BD55K in my case) with a non HDMI receiver for audio. I am sending the video directly via HDMI to my PJ.

 

[billy p]

PCM if your receiver can't decode the new formats and send it analog or via older HDMI receiver and bitstream only if it CAN decode. Bitstream gives you added flexibility because you can use the receivers digital surround processors to decode and apply proper B/M with the incoming signal. Outside of that I don't know much else and learning through trail and error.

 

[cavaleri]

Thanks for your thoughts; I should have added that my older Marantz SR9300 does not have HDMI inputs. I am using both the digital optical output, as well as the 7.1 analog outputs. Like you, I'm experimenting. It seems that so far, I can tell a nice difference when playing THX movies that are bitstreamed from the player. The Marantz recognizes this, and can further enhance by matrixing the 5.1 channels to the 7.1 speakers. However, for non THX material, I am still in need of solutions/suggestions. I'll keep experimenting as well, and post any findings here.

Thanks again.

 

[Tomorrow]

Similar situation here...would love to know what is the best set up for a BD Player (BD55K in my case) with a non HDMI receiver for audio. I am sending the video directly via HDMI to my PJ.

You might want to read this thread where these exact setup issues were resolved.

http://forums.audioholics.com/forums/showthread.php?t=50480

 

[timplett]

I've got a bit of a different issue. I've got an older Sherwood amplifier, not sure how old but I believe it's pre-DTS. I've always run everything as bitstream because it has always worked better (better sound, better surround). I just got a LCD tv so I borrowed my father-in-law's Bluray player. It's audio options were Auto and 2chPCM. Auto still put out PCM so I don't know why it was there. At certain points throughout the movie it would make loud popping noises. I turned the volume way down and it would still make it so I know it wasn't my speakers. My only guess is that my receiver can't handle PCM for whatever reason. The BD is connectedby HDMI to the TV and an optical cable goes from the TV to the receiver. When I listened to the movie through the TV there were no issues.