Another PCM vs Bitstream Question

[JayAuritt]

I know that these kind of questions have been asked to death, but I don't recall seeing specific info regarding this question:

I have a PS3 hooked up via HDMI to an Onkyo 805 hdmi 1.3-capable receiver. As there is no capability to receiver DD TrueHD and DTS MA HD in the PS3 yet, I have the PS3 audio set to Linear PCM rather than Bitstream.

When I play a standard DVD in the PS3 that has DTS audio, the DTS icon on the front of the receiver does not light up. So, I'm wondering if the receiver is outputting DTS in this situation, or would I need to change from PCM to Bitstream in the PS3 in order to receive DTS?

[degas]

If PS3 set to Bitstream:
The receiver decodes DD/DTS as usual.

If PS3 set to PCM:
PS3 decodes DD/DTS and sends the audio as PCM (that's why the logos don't light up on your receiver).

[JayAuritt]

Originally Posted by degas

If PS3 set to Bitstream:
The receiver decodes DD/DTS as usual.

If PS3 set to PCM:
PS3 decodes DD/DTS and sends the audio as PCM (that's why the logos don't light up on your receiver).

Okay, thanks...just one more question: is there any difference in the audio quality when the DTS is sent as PCM?

[HDJK]

Originally Posted by JayAuritt

Okay, thanks...just one more question: is there any difference in the audio quality when the DTS is sent as PCM?

You're entering the esoteric realm with this question

But seriously, the only real difference is, that some receivers cannot apply any additional processing (like Dolby PLII, THX surround modes etc.) to PCM streams. So if you're into enhanced surround sound and your reciever doesn't support it on PCM you'll have to go bitstream.

edit:
There are people who claim that packed audio streams are less sensitive to digital jitter than PCM streams, but the opinions do vary on this one.

[JayAuritt]

Originally Posted by HDJK

You're entering the esoteric realm with this question

But seriously, the only real difference is, that some receivers cannot apply any additional processing (like Dolby PLII, THX surround modes etc.) to PCM streams. So if you're into enhanced surround sound and your reciever doesn't support it on PCM you'll have to go bitstream.

edit:
There are people who claim that packed audio streams are less sensitive to digital jitter than PCM streams, but the opinions do vary on this one.

Thanks...sounds like it would just be safer to switch to Bitstream on the PS3 when playing a Blu-ray or DVD that does NOT have PCM.

[crackinhedz]

The Onkyo 805 can apply post processing to the PCM signal so you would be ok to leave as PCM...unless you want your reciever to display "Dolby Digital", "DTS"..etc


Bitstream vs. PCM debate

Jitter sensitivity

"In investigating the requirements of a high-resolution audio system, it is evident that jitter performance is paramount - an area already given wide discussion in the technical literature. A bitstream code that simultaneously contains high-amplitude and high-frequency noise is susceptible to jitter - where intermodulation with timing jitter can fold signal energy into the audio band and thus compromise performance. In this area, it is believed that bitstream is inherently more jitter-susceptible than multi-bit systems."

....

Conclusion

"PCM with transparent data compression offers an uncompromised efficient code that is fully compatible with advanced recording and replay processes.

We consider that these advantages of PCM far outweigh the basic advantages of bitstream and we therefore recommend a losslessly-packed linear PCM system to you for formal adoption."

[JayAuritt]

Originally Posted by crackinhedz

The Onkyo 805 can apply post processing to the PCM signal so you would be ok to leave as PCM...unless you want your reciever to display "Dolby Digital", "DTS"..etc"

Thanks for the info...I guess I don't need to actually see the DD/DTS logo displayed as long as I know that's what I'm getting.

[aqupunk]

Originally Posted by crackinhedz

The Onkyo 805 can apply post processing to the PCM signal so you would be ok to leave as PCM...unless you want your reciever to display "Dolby Digital", "DTS"..etc


Bitstream vs. PCM debate

Jitter sensitivity

"In investigating the requirements of a high-resolution audio system, it is evident that jitter performance is paramount - an area already given wide discussion in the technical literature. A bitstream code that simultaneously contains high-amplitude and high-frequency noise is susceptible to jitter - where intermodulation with timing jitter can fold signal energy into the audio band and thus compromise performance. In this area, it is believed that bitstream is inherently more jitter-susceptible than multi-bit systems."

....

Conclusion

"PCM with transparent data compression offers an uncompromised efficient code that is fully compatible with advanced recording and replay processes.

We consider that these advantages of PCM far outweigh the basic advantages of bitstream and we therefore recommend a losslessly-packed linear PCM system to you for formal adoption."

So I notice a difference between linear pcm and bitstream. I feel linear pcm sounds better but at the same time I can't enjoy 7.1 with it. Is there any way around this or should I just accept it?

[crackinhedz]

Originally Posted by aqupunk

So I notice a difference between linear pcm and bitstream. I feel linear pcm sounds better but at the same time I can't enjoy 7.1 with it. Is there any way around this or should I just accept it?

which reciever are you using?

[aqupunk]

Originally Posted by crackinhedz

which reciever are you using?

Onkyo 605

[crackinhedz]

Originally Posted by aqupunk

So I notice a difference between linear pcm and bitstream. I feel linear pcm sounds better but at the same time I can't enjoy 7.1 with it. Is there any way around this or should I just accept it?

sorry the Onkyo 605 does not post process a PCM signal....

But 5.1 uncompressed is awesome anyways... the Onkyo can do 7.1 PCM, so just find titles that use all 7.1 (Lionsgate starting to use 7.1 PCM...and theres a few others)...but for 5.1 PCM thats all you will get. Which honestly, unless its discrete 7.1, all postprocessing is, is matrixing the surround channels...its not a real "back" channel, so youre not missing out on too much.

[aqupunk]

Originally Posted by crackinhedz

sorry the Onkyo 605 does not post process a PCM signal....

But 5.1 uncompressed is awesome anyways... the Onkyo can do 7.1 PCM, so just find titles that use all 7.1 (Lionsgate starting to use 7.1 PCM...and theres a few others)...but for 5.1 PCM thats all you will get. Which honestly, unless its discrete 7.1, all postprocessing is, is matrixing the surround channels...its not a real "back" channel, so youre not missing out on too much.

So on my bdp-s300 I should change all audio settings to pcm? Such as Dolby Digital, DTS? And what should I set the DTS Downmix to, Stereo or Lt/Rt?

[crackinhedz]

Originally Posted by aqupunk

So on my bdp-s300 I should change all audio settings to pcm? Such as Dolby Digital, DTS? And what should I set the DTS Downmix to, Stereo or Lt/Rt?

well...since the bdp-s300 cannot decode dolby trueHD...then you should be ok just setting bitstream. (or "auto", whatever is the choice)...

when you select the uncompressed PCM track it will automatically send linear pcm. But when you select dolby or dts it will bitstream so your reciever can decode and apply post processing (prologicIIx etc)


...as for "DTS downmix"...I would say turn it "off" (is that a choice?).

[aqupunk]

Originally Posted by crackinhedz

well...since the bdp-s300 cannot decode dolby trueHD...then you should be ok just setting bitstream. (or "auto", whatever is the choice)...

when you select the uncompressed PCM track it will automatically send linear pcm. But when you select dolby or dts it will bitstream so your reciever can decode and apply post processing (prologicIIx etc)


...as for "DTS downmix"...I would say turn it "off" (is that a choice?).

No it isn't a choice it is either DTS or downmix pcm.

So really auto sounds a little different then pcm. So what your saying is bitstream will be the same as just multichannel pcm, and it will post process prologicIIx, and that s the best I can do with my sony and onkyo 605.

[crackinhedz]

Originally Posted by aqupunk

No it isn't a choice it is either DTS or downmix pcm.

So really auto sounds a little different then pcm. So what your saying is bitstream will be the same as just multichannel pcm, and it will post process prologicIIx, and that s the best I can do with my sony and onkyo 605.

ok, im not sure about the DTS or downmix pcm...you just said earlier, "downmix dts"...

when I say set to "auto"...what this does is basically the same concept as bitstream, it will send standard dolby digital and dts to your reciever, and your reciever will decode. If you happen to slect the Uncompressed PCM track, it will send it as Linear PCM anyways.

Now, if you were to set to output as PCM instead of "auto" what would happen is the player will deocde internally into a pcm signal, and then send it to the reciever, and since your reciever cannot post process a pcm signal, you will be stuck with 5.1 dolby digital and dts. Now, set to "auto" it will send bitstream, which your reciever can then take the dolby digital and dts, decode it, and then post process it with pro logicIIx etc.

I know it doesnt make sense, just trust.


im gonna go read your manual. get back in a bit.

[crackinhedz]

ok,pg.47 in manual, for:

Dolby Digital -> Dolby Digital

DTS -> DTS

DTS downmix -> Lt/Rt

Audio (HDMI) -> Auto



("DTS downmix" is for if you set DTS->Downmix PCM...but since you set DTS->DTS, it shouldnt affect you)

[aqupunk]

Originally Posted by crackinhedz

ok,pg.47 in manual, for:

Dolby Digital -> Dolby Digital

DTS -> DTS

DTS downmix -> Lt/Rt

Audio (HDMI) -> Auto



("DTS downmix" is for if you set DTS->Downmix PCM...but since you set DTS->DTS, it shouldnt affect you)

Alright, thanks for your help I totally appreciate and I will stop messing with it and just enjoy it. Thanks again!

[HDJK]

Originally Posted by crackinhedz

...
Bitstream vs. PCM debate

Jitter sensitivity

"In investigating the requirements of a high-resolution audio system, it is evident that jitter performance is paramount - an area already given wide discussion in the technical literature. A bitstream code that simultaneously contains high-amplitude and high-frequency noise is susceptible to jitter - where intermodulation with timing jitter can fold signal energy into the audio band and thus compromise performance. In this area, it is believed that bitstream is inherently more jitter-susceptible than multi-bit systems."

....

Conclusion

"PCM with transparent data compression offers an uncompromised efficient code that is fully compatible with advanced recording and replay processes.

We consider that these advantages of PCM far outweigh the basic advantages of bitstream and we therefore recommend a losslessly-packed linear PCM system to you for formal adoption."

Interesting read. Thanks for that. Am I surprised that the A-man said exactly the opposite over at AVMS? Not really

[Sir Terrence]

Originally Posted by HDJK

Interesting read. Thanks for that. Am I surprised that the A-man said exactly the opposite over at AVMS? Not really

The A-man doesn't quite know what he is talking about half the time, especially when it comes to audio codecs.

I have had to correct him several times on the issue of bitstream vs PCM over at AVMS on a few occasions. I ripped him a new one here when he tried to say that Dolby Digital is a better codec than Dts. Those of us who have worked with both know better

[mikebijt]

Originally Posted by crackinhedz

sorry the Onkyo 605 does not post process a PCM signal....

But 5.1 uncompressed is awesome anyways... the Onkyo can do 7.1 PCM, so just find titles that use all 7.1 (Lionsgate starting to use 7.1 PCM...and theres a few others)...but for 5.1 PCM thats all you will get. Which honestly, unless its discrete 7.1, all postprocessing is, is matrixing the surround channels...its not a real "back" channel, so youre not missing out on too much.

Hi. I'm a new Onkyo 605 owner. Can you tell me how I know that the PCM signal I receive is indeed a multi channel PCM signal and not a two channel signal? And what surround mode should I best use for listening to a 5.1 uncompressed PC signal (for example Prologic II or DTS Neo:6 or...)??

Thanks!