PCM and Bitstream (TrueHD)

[miggs29]

I was reading a mag at B&N and it was talking about how to set up your BD and AVR if your AVR does not support TrueHD. It said to set the BD to send audio as PCM in order for the AVR to receive audio as TrueHD based on the BD decoder istead of the AVR. Is that correct? I was checking my set up and if I do that the AVR shows the audio as MPCM istead of dolby. Will that be the case for DTS too? It seems to me that it should be set to bitstream on the BD player so that I can hear Dolby or DTS. Am I missing something?

AVR RX-V1700
BD DMP-BD55

 

[GlocksRock]

If the blu ray player is doing the decoding internally, all formats that are sent out to the AVR will be sent as PCM, this includes all flavors of dolby digital as well as DTS. If your player is capable of outputting bitstream over HDMI and your receiver can decode the latest HD audio formats, then you will see your receiver display the TrueHD or DTS HD Master Audio logo(s). Just because you see MPCM on your receiver doesn't mean you aren't hearing dolby true hd or dts hd master audio, it just means that it has already been decoded by the player.

 

[GlocksRock]

After looking at the specs for your receiver, the RX-V1700 does not have HD audio decoders built in, so you will have to live with PCM audio. But it does look like your blu ray player can output HD audio via bitstream, so if you ever decide to upgrade your receiver you can bitstream and see the lights on your avr display what you are hearing.

 

[Nugu]

Just so it's clear when he says "live with pcm" I'm pretty sure that's sarcasm directed at the people who are anal retentive enough to need the light on the receiver to vindicate them.

To reiterate, TrueHD sent to the receiver via PCM or bitstream is the same when played.

 

[miggs29]

After looking at the specs for your receiver, the RX-V1700 does not have HD audio decoders built in, so you will have to live with PCM audio. But it does look like your blu ray player can output HD audio via bitstream, so if you ever decide to upgrade your receiver you can bitstream and see the lights on your avr display what you are hearing.

Thank you for your quick reply.

Should I set the BD player to send audio as PCM or bitstream? The manual is a bit confusing to me.

 

[trnqk7]

Set the output to PCM, your AVR doesn't accept bitstreamed HD audio. Let the player do the decoding.

 

[miggs29]

Set the output to PCM, your AVR doesn't accept bitstreamed HD audio. Let the player do the decoding.

I tried PCM on the BD player and the SQ is not as good as when I set it to bitstream. Do I need to set up the AVR differently if the player is set to PCM. I just want to make sure that I hear the audio on the movie as trueHD or DTS-HD or as intended. Do I also need to pick a specific sound field on the AVR? Currently is set to neural surround.

 

[trnqk7]

Don't use the neural surround. Set it to "Direct" or some equivalent-in essence, a mode that doesn't alter the incoming signal by trying to make it more spacious like neural surround. "Direct" is what it's called on my Denon AVR, I'll hope that a Yamaha user will chime in with the equivalent name of the mode for that brand, if it's any different.

BTW, your AVR, when receiving bitstream, is still internally converting it to PCM. So it shouldn't matter which one you send it in general.

 

[TLS Guy]

I tried PCM on the BD player and the SQ is not as good as when I set it to bitstream. Do I need to set up the AVR differently if the player is set to PCM. I just want to make sure that I hear the audio on the movie as trueHD or DTS-HD or as intended. Do I also need to pick a specific sound field on the AVR? Currently is set to neural surround.

Your receiver will not let you hear it as Dolby True HD or DTS HD. Your receiver can not decode those codecs, so will default to Dolby digital or DTS, using the lossy codecs.

The only way around this is if your player has analog 7.1 out and your player 7.1 analog inputs. However you will have to do level, bass management and delay at the player level.

If you want to hear the new loss less codecs, your best bet is a receiver upgrade.

 

[avliner]

TLS,

please correct me if I'm wrong, but my understanding is that he can use HDMI cable as well, assuming the AVR accepts LPCM (all with MCH inputs does).

The only "must" is to let the player doing the decoding of the HD codecs.

 

[TLS Guy]

TLS,

please correct me if I'm wrong, but my understanding is that he can use HDMI cable as well, assuming the AVR accepts LPCM (all with MCH inputs does).

The only "must" is to let the player doing the decoding of the HD codecs.

You are not correct. If a receiver does not have the ability to decode the loss less codecs, it will default to the lossy ones whether it is sent bit stream or PCM.

If the receiver or pre pro does not have the new codecs, the only work around is an analog connection.

 

[dkane360]

TLS,

please correct me if I'm wrong, but my understanding is that he can use HDMI cable as well, assuming the AVR accepts LPCM (all with MCH inputs does).

The only "must" is to let the player doing the decoding of the HD codecs.

I'm pretty sure that multichannel LPCM over HDMI will work.

EDIT- I posed this question a while ago when I was researching receivers, and I was told that if it accepts 7.1 LPCM over HDMI, that it would be the equivalent of TrueHD or DTSMA, as long as the player decoded it to LPCM.

 

[sholling]

I'm pretty sure that multichannel LPCM over HDMI will work.

The player should be set for PCM and the receiver set for multichannel LPCM. If that doesn't do the job then it's time for a receiver upgrade but this is exactly what PS/3 owners have been doing.

 

[TLS Guy]

I'm pretty sure that multichannel LPCM over HDMI will work.

EDIT- I posed this question a while ago when I was researching receivers, and I was told that if it accepts 7.1 LPCM over HDMI, that it would be the equivalent of TrueHD or DTSMA, as long as the player decoded it to LPCM.

I have just looked into this again. It seems some chip sets can decode multichannel loss less codecs over HDMI using LPCM. The receiver needs to be HDMI version 1.3 and state that it can handle multichannel over LPCM. Most older receivers to not have the correct chip set to do this. So it seems this has got to be a confusing area.

But if it is HDMI 1.3 and says it can do 7.1 over HDMI it should be decode it properly.

 

[avliner]

I'm pretty sure that multichannel LPCM over HDMI will work.

EDIT- I posed this question a while ago when I was researching receivers, and I was told that if it accepts 7.1 LPCM over HDMI, that it would be the equivalent of TrueHD or DTSMA, as long as the player decoded it to LPCM.

So as I, as I've always read this. If you have a player that can't decode instead, then you'll have lossy audio (core track).

In the other end, the AVR must accept LPCM 7.1 to get HD lossless audio.
MC inputs applies to AVR's without HDMI connections though.

Anyone else would like to chime in, please??

 

[jostenmeat]

I have just looked into this again. It seems some chip sets can decode multichannel loss less codecs over HDMI using LPCM. The receiver needs to be HDMI version 1.3 and state that it can handle multichannel over LPCM. Most older receivers to not have the correct chip set to do this. So it seems this has got to be a confusing area.

But if it is HDMI 1.3 and says it can do 7.1 over HDMI it should be decode it properly.

Doc, all versions of HDMI (assuming it's not just video pass thru only), can handle 8 channels of mch PCM, at 192khz. This even includes HDMI 1.0.

My preliminary off the cuff recommendations to anyone new to this stuff:

1. Make sure you chose the right codec on the disc itself!
2. My personal recommendation is to defeat any DRC inside the player.
3. Some receivers cannot matrix the rear speakers from a 5.1 PCM source. However, some receivers have available FW that finally allows them to do so. If not, then you only get 7.1 when the disc is natively 7.1.

avliner, your Pana bdp is capable of decoding all of the relevant formats, so go into menu to make sure TrueHD+DTSMA are set to output as mch PCM. Make sure that PCM downmix to 2.0 remains defeated. Good luck.

If you feel that it doesn't sound as good, well, it's possible that the volume is simply different. They often say louder sounds better. I've once compared a lossy vs lossless track on a certain movie, and the lossy bitstream was louder.

 

[avliner]

...avliner, your Pana bdp is capable of decoding all of the relevant formats, so go into menu to make sure TrueHD+DTSMA are set to output as mch PCM...

Hi Josten,

there's gotta be a misunderstanding though, as my Panny -30 does not have internal decoding, so I always set it to bitstream, unless the BD media is recorded in LPCM (5.1 uncompressed raw lpcm).

With my Oppo-80, I always prefer LPCM anyway...

 

[yepimonfire]

MPCM is multichannel audio, it would be the same as if you listened to the HD audio using a receiver decoder except the audio is already decompressed into raw data, it is lossless. i would set your receiver to AUTO or whatever setting is similar.

 

[jostenmeat]

Hi Josten,

there's gotta be a misunderstanding though, as my Panny -30 does not have internal decoding, so I always set it to bitstream, unless the BD media is recorded in LPCM (5.1 uncompressed raw lpcm).

With my Oppo-80, I always prefer LPCM anyway...

Yes, I'm sorry, I got confused when typing the post. I really meant to refer to the OP, miggs29, who does have a Pana BDP 55 listed in his sig. Cheers.

miggs29 I looked around, and found no evidence that it can matrix 5.1 PCM for the rears in a 7.1 setup. I thought* the Yam 663 had a FW that allowed it to finally matrix 5.1 PCM (though I think it still cannot for the bitstreamed versions).

I also did not see any note of allowing matrixing when I found this post regarding FWs for 1700/2700:
http://www.avsforum.com/avs-vb/showpost.php?p=12776439&postcount=3846

 

[GlocksRock]

I owned the RX-V1600 and it was able to apply PLIIx to a 5.1 PCM source, but the RX-V1600 was not capable of accepting 7.1 PCM, this is per my own experiments, and per Yamaha. I'm not sure if the RX-V1700 can accept 7.1 PCM over HDMI, but it should definitely be able to apply PLIIx to a 5.1 source for a 7.1 experience which is very good. I use PLIIx for everything that isn't natively 7.1. I know the RX-V1700 has 8 ch. analog inputs, so those could also be used for 7.1 PCM if it can't be done over HDMI, but I'm pretty sure his blu ray player doesn't have analog outputs.