Bitstream vs PCM... - Blu-ray Forum

Mike_In_HD · 01-12-2009, 05:30 PM

Can someone explain the difference to me... or at least post a link to a good source?

Isn't bitstream the "truest" sound? Should I set my BD player to this?

PS3+HDDVD OWNER · 01-12-2009, 05:33 PM

Quote:

Originally Posted by Mike_In_HD

Can someone explain the difference to me... or at least post a link to a good source?

Isn't bitstream the "truest" sound? Should I set my BD player to this?

Why dont you post your current setup?
Do you have an A/V Receiver?
Speaker Setup?
What kind of tv?
What BD Player?

Pelican170 · 01-12-2009, 05:36 PM

They are both the same. one has the player decoding and sending it and the other has the receiver decoding it. some say the volume is louder when bitstreaming, thats all...

My_Two_Cents · 01-12-2009, 05:43 PM

Analogy (simplified):

Bitstream = Take an audio file, compress it (zip-it), send it to an AVR, uncompress it (unzip it), play it

LPCM = Take an audio file, send it to an AVR, play it

Is your file going to be any different after you unzip it? No. It's the same data file. Volume may be different, but the data is the same.

PS3+HDDVD OWNER · 01-12-2009, 05:43 PM

Quote:

Originally Posted by Pelican170

They are both the same. one has the player decoding and sending it and the other has the receiver decoding it. some say the volume is louder when bitstreaming, thats all...

Never heard that before, i guess i am mistaken. Thanks for posting!

All i know is, either way HD AUDIO ROCKS!!

Mike_In_HD · 01-12-2009, 05:43 PM

Why is this technology so convoluted?...

My setup from the top of my head:

46" Sharp Aquos
Sharp Aquos BD HP20
Toshiba HD A30
Sony - 500W 5.1-Ch. A/V Receiver
Polk Audio SW
Technics R,L,Cntr,RR,RL

Oh... & Directv FTW...

Pelican170 · 01-12-2009, 05:46 PM

Quote:

Originally Posted by PS3+HDDVD OWNER

Never heard that before, i guess i am mistaken. Thanks for posting!

All i know is, either way HD AUDIO ROCKS!!

No prob. Yes, it ROCK!!!!

surfdude12 · 01-12-2009, 05:56 PM

Quote:

Originally Posted by Mike_In_HD

Why is this technology so convoluted?...

My setup from the top of my head:

46" Sharp Aquos
Sharp Aquos BD HP20
Toshiba HD A30
Sony - 500W 5.1-Ch. A/V Receiver
Polk Audio SW
Technics R,L,Cntr,RR,RL

Oh... & Directv FTW...

i don't think that receiver has an internal PCM/DTS-HD/Dolby-HD decoder:

http://www.bestbuy.com/site/olspage....=1200703058274
(i see it has regular DTS/Dolby decoding, and HDMI pass-through)

so "bitstream" would only give you regular DTS/Dolby. I would put it on "PCM" if you can, then hopefully your player will decode PCM/DTS-HD/Dolby-HD and spit out PCM to your receiver.

My_Two_Cents · 01-12-2009, 05:59 PM

Quote:

Originally Posted by Mike_In_HD

Why is this technology so convoluted?...

My setup from the top of my head:

46" Sharp Aquos
Sharp Aquos BD HP20
Toshiba HD A30
Sony - 500W 5.1-Ch. A/V Receiver
Polk Audio SW
Technics R,L,Cntr,RR,RL

Oh... & Directv FTW...

What is the model number of your AVR? Does it decode HD audio? Does it accept audio over HDMI?

Edit: As your player does not bitstream HD audio, your only option is to player decode Dolby True HD (you won't be able to decode DTS HD as your player doesn't support it) and send the audio as LPCM to your AVR (assuming your AVR accepts audio over HDMI, some don't).

Russell_L · 01-12-2009, 07:14 PM

Here's a simplified explanation as I understand it:

1. All audio codecs on a Blu-ray disc (PCM, DTS-MA, Dolby TrueHD, etc.) are encoded digitally and must be decoded and converted to analog in order for you to hear the sound. All audio codecs other than PCM are compressed; some are lossy (like regular Dolby Digital) and some are lossless (like DTS-MA and Dolby TrueHD). Lossless codecs, when decoded and converted to analog, are equivalent in quality (at least in theory) to uncompressed PCM.

2. Where this decoding and digital-to-analog (D-A) conversion takes place depends on the capabilities of your BD player and your receiver/amplifier/pre-pro.

3. Some BD players allow you to send the native audio codec as a bitstream via HDMI to your receiver/amplifier/pre-pro and let the latter component do the decoding and D-A conversion. (Some BD players (like the PS3) decode the audio codecs internally to PCM and output that PCM signal via HDMI to the receiver/amplifier/pre-pro for D-A conversion.) I might be wrong on this, but I don't think it's possible for a BD player to send the native audio bitstream of DTS-MA and Dolby TrueHD via Toslink or coax.

4. Most BD players can do the decoding and D-A conversion internally (of some or all of the codecs) and output the analog signal via the player's analog outputs to the analog inputs of the receiver/amplifier/pre-pro. This is useful when the receiver/amplifier/pre-pro cannot handle some of the more advanced audio codecs, like DTS-MA or Dolby TrueHD.

Mike_In_HD · 01-12-2009, 07:24 PM

How will you know if your receiver cannot handle a certain quality? And what then does it do it the sound?

My_Two_Cents · 01-12-2009, 07:38 PM

Quote:

Originally Posted by Mike_In_HD

How will you know if your receiver cannot handle a certain quality? And what then does it do it the sound?

Again, provide your AVR model number and we can help. If it doesn't accept HDMI audio, then the best you will get is lossy DD or DTS via optical.

Mike_In_HD · 01-12-2009, 07:41 PM

It does get audio via HDMI... How much worse is sound via optical?

G@zz@ · 01-12-2009, 07:49 PM

If your receiver does not have HDMI inputs, then it defo does not decode the HD audio formats. But some do have HDMI on them but they just pass through and do no audio decoding. This is handy if your TV only has say only 1 HDMI on it. You can connect several devices to the receiver and then output to the TV. All the receiver is doing is passing the sign through, with no processing.... and the TV does all the picture scaling. But you would get no upscaling from the receiver or HD audio.

If your receiver has the 5.1/7.1 analogue inputs on the back, then you have to buy a Blu-ray player that has the analogue outs and does all the decoding on board the player. Then you will get HD audio. But I have read time and time again that people who have purchased the latest HD audio receivers and now bitstream, find the sound a lot better. But I guess that's a personal choice, as we all hear different things.

Your speakers are obviously a deciding factor too as to how good the HD audio will sound.

I have the Panasonic BD55 using the analogue outs and it sounds awesome. But then again I do have some very good speakers and a decent receiver.

So in a nutshell, your receiver needs to have HDMI inputs and needs to be able to decode the HD audio... or it must have 5.1/7.1 analogue inputs and the Blu-ray player requires 5.1/7.1 analogue outs and must be able to decode all the HD formats.

You can not get HD audio from digital coaxial or optical connections, it will just down mix to standard Dolby Digital or DTS.

saprano · 01-12-2009, 07:53 PM

Quote:

Originally Posted by Mike_In_HD

Why is this technology so convoluted?...

My setup from the top of my head:

46" Sharp Aquos
Sharp Aquos BD HP20
Toshiba HD A30
Sony - 500W 5.1-Ch. A/V Receiver
Polk Audio SW
Technics R,L,Cntr,RR,RL

Oh... & Directv FTW...

How do you use direct? yea its as clean as vergin, but it sounds flat. no bass or dynamics.

jkwest · 01-12-2009, 07:54 PM

why wouldn't you ask this in our Audio area?

01-12-2009, 05:30 PM	#1
Mike_In_HD Active Member Member since:Oct 2008 Location:Ohio Blu-ray collection:968	Bitstream vs PCM... Can someone explain the difference to me... or at least post a link to a good source? Isn't bitstream the "truest" sound? Should I set my BD player to this?

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01-12-2009, 05:36 PM	#3
Pelican170 Blu-ray Samurai Member since:Jul 2007 Location:Newtown, CT 4K collection:127 Blu-ray collection:735 DVD collection:256 Trading Score:13	They are both the same. one has the player decoding and sending it and the other has the receiver decoding it. some say the volume is louder when bitstreaming, thats all...

01-12-2009, 05:43 PM	#4
My_Two_Cents Blu-ray Knight Top contributor Member since:Dec 2007 Location:Wherever I may roam.... Home Theater Gallery:40 4K collection:35 Blu-ray collection:507 DVD collection:19 Blu-ray reviews: 1 Trading Score:4	Analogy (simplified): Bitstream = Take an audio file, compress it (zip-it), send it to an AVR, uncompress it (unzip it), play it LPCM = Take an audio file, send it to an AVR, play it Is your file going to be any different after you unzip it? No. It's the same data file. Volume may be different, but the data is the same.

01-12-2009, 07:14 PM	#10
Russell_L Senior Member Member since:Nov 2007 Location:San Francisco Home Theater Gallery:2 4K collection:3 Blu-ray collection:800 DVD collection:1 Blu-ray reviews: 11	Here's a simplified explanation as I understand it: 1. All audio codecs on a Blu-ray disc (PCM, DTS-MA, Dolby TrueHD, etc.) are encoded digitally and must be decoded and converted to analog in order for you to hear the sound. All audio codecs other than PCM are compressed; some are lossy (like regular Dolby Digital) and some are lossless (like DTS-MA and Dolby TrueHD). Lossless codecs, when decoded and converted to analog, are equivalent in quality (at least in theory) to uncompressed PCM. 2. Where this decoding and digital-to-analog (D-A) conversion takes place depends on the capabilities of your BD player and your receiver/amplifier/pre-pro. 3. Some BD players allow you to send the native audio codec as a bitstream via HDMI to your receiver/amplifier/pre-pro and let the latter component do the decoding and D-A conversion. (Some BD players (like the PS3) decode the audio codecs internally to PCM and output that PCM signal via HDMI to the receiver/amplifier/pre-pro for D-A conversion.) I might be wrong on this, but I don't think it's possible for a BD player to send the native audio bitstream of DTS-MA and Dolby TrueHD via Toslink or coax. 4. Most BD players can do the decoding and D-A conversion internally (of some or all of the codecs) and output the analog signal via the player's analog outputs to the analog inputs of the receiver/amplifier/pre-pro. This is useful when the receiver/amplifier/pre-pro cannot handle some of the more advanced audio codecs, like DTS-MA or Dolby TrueHD.

01-12-2009, 07:24 PM	#11
Mike_In_HD Active Member Member since:Oct 2008 Location:Ohio Blu-ray collection:968	How will you know if your receiver cannot handle a certain quality? And what then does it do it the sound?

01-12-2009, 07:41 PM	#13
Mike_In_HD Active Member Member since:Oct 2008 Location:Ohio Blu-ray collection:968	It does get audio via HDMI... How much worse is sound via optical?

01-12-2009, 07:49 PM	#14
G@zz@ Active Member Member since:Dec 2008 Location:United Kingdom Home Theater Gallery:14 Blu-ray collection:571 Trading Score:18	If your receiver does not have HDMI inputs, then it defo does not decode the HD audio formats. But some do have HDMI on them but they just pass through and do no audio decoding. This is handy if your TV only has say only 1 HDMI on it. You can connect several devices to the receiver and then output to the TV. All the receiver is doing is passing the sign through, with no processing.... and the TV does all the picture scaling. But you would get no upscaling from the receiver or HD audio. If your receiver has the 5.1/7.1 analogue inputs on the back, then you have to buy a Blu-ray player that has the analogue outs and does all the decoding on board the player. Then you will get HD audio. But I have read time and time again that people who have purchased the latest HD audio receivers and now bitstream, find the sound a lot better. But I guess that's a personal choice, as we all hear different things. Your speakers are obviously a deciding factor too as to how good the HD audio will sound. I have the Panasonic BD55 using the analogue outs and it sounds awesome. But then again I do have some very good speakers and a decent receiver. So in a nutshell, your receiver needs to have HDMI inputs and needs to be able to decode the HD audio... or it must have 5.1/7.1 analogue inputs and the Blu-ray player requires 5.1/7.1 analogue outs and must be able to decode all the HD formats. You can not get HD audio from digital coaxial or optical connections, it will just down mix to standard Dolby Digital or DTS.

01-12-2009, 07:54 PM	#16
jkwest Off-Topic King Member since:Jul 2007 Location:Northern California PSN Id: jkwest5 Blu-ray reviews:1 Trading Score:20	why wouldn't you ask this in our Audio area?

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