Bitstream or PCM? - Page 4 - AVS Forum
Forum Jump: 
Reply
 
Thread Tools
post #91 of 99 Old 01-18-2013, 08:36 AM
AVS Special Member
 
Foxbat121's Avatar
 
Join Date: Jul 2003
Location: VA
Posts: 9,801
Mentioned: 1 Post(s)
Tagged: 0 Thread(s)
Quoted: 107 Post(s)
Liked: 196
Quote:
Originally Posted by David Susilo View Post

At least in theory, if we do the conversion on the player, the CPU/GPU on the receiver will not have to work as hard and have the possibility of producing better sound quality.

Am I right, am I wrong?

Way to revive the almost 4-year old thread smile.gif

I don't think you will see any difference at all. These receivers often have dedicated DSPs just for decompressing the audio. Besides, decompressing HD audio doesn't use that much horse power anyway (think any $50 BD player can do it today without sweet). If you are worried that your AVR will be over taxed for a little bit extra decoding, you probably bought the wrong AVR.

In fact, there are some advantages of bitstream and let AVR do the decoding when dealing with DTS-HD audio. DTS-HD uses a special speaker mapping algorithm embedded into each DTS-HD stream. So, for commonly encountered DTS-HD MA 5.1 audio tracks, most of them don't exactly map into a LPCM 5.1 audio stream due to this speaker mapping. In fact, all Panasonic BD players will output LPCM 7.1 all the time whenever it decodes any type of DTS audio. The players simply has no clue how is your 7.1 speakers located and can only make a generic mapping. On the other hand, your AVR knows exactly how your 7.1 speakers setup (you tell it during the setup and also from calibration). So, in theory, your AVR can make a more accurate speaker mapping when it is decoding the DTS-HD stream.
Foxbat121 is online now  
Sponsored Links
Advertisement
 
post #92 of 99 Old 01-18-2013, 08:41 AM
AVS Addicted Member
 
rboster's Avatar
 
Join Date: Jul 2000
Location: USA
Posts: 17,547
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 16 Post(s)
Liked: 57
Quote:
Originally Posted by Foxbat121 View Post

Way to revive the almost 4-year old thread smile.gif

.

He didn't, I did by merging this thread into an existing thread on the same topic...comparison of Bitstream and PCM. There were a number of threads here and other HD software forum discussing the differences/perferences, but this one was the largest.

"Retired" AVS Moderator
rboster is online now  
post #93 of 99 Old 01-18-2013, 04:58 PM
AVS Special Member
 
Kilian.ca's Avatar
 
Join Date: Mar 2007
Location: Ex-50Hz, now 60Hz
Posts: 1,901
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
Liked: 36
Quote:
Originally Posted by Foxbat121 View Post

I don't think you will see any difference at all.

There are some specific situations where there is a difference. A few years ago on the AVR forum here some reported that PCM and bitstream had volume differences on Onkyo AVRs and no one got to the bottom of it. Also there's a long thread on Blu-ray.com mentioning some other scenarios.
Quote:
Originally Posted by Foxbat121 View Post

These receivers often have dedicated DSPs just for decompressing the audio.

I thought the same too, hence my mention of what the DSP does to digital audio. I'm not sure if the decoder is always a separate DSP from the main DSP doing other things without the schematics.
Quote:
Originally Posted by Foxbat121 View Post

Besides, decompressing HD audio doesn't use that much horse power anyway (think any $50 BD player can do it today without sweet). If you are worried that your AVR will be over taxed for a little bit extra decoding, you probably bought the wrong AVR.

A few years ago the AVRs could not both decode dts-HD MA and do room correction at the same time. They could if sent PCM. Or they could decode but not apply RC. Or they could do both but limited to 48kHz or 96kHz but not 192kHz sample rates. Of course this is now no longer the case.
Quote:
Originally Posted by Foxbat121 View Post

In fact, there are some advantages of bitstream and let AVR do the decoding when dealing with DTS-HD audio. DTS-HD uses a special speaker mapping algorithm embedded into each DTS-HD stream. So, for commonly encountered DTS-HD MA 5.1 audio tracks, most of them don't exactly map into a LPCM 5.1 audio stream due to this speaker mapping. In fact, all Panasonic BD players will output LPCM 7.1 all the time whenever it decodes any type of DTS audio. The players simply has no clue how is your 7.1 speakers located and can only make a generic mapping. On the other hand, your AVR knows exactly how your 7.1 speakers setup (you tell it during the setup and also from calibration). So, in theory, your AVR can make a more accurate speaker mapping when it is decoding the DTS-HD stream.

The dts speaker mapping is only found in a few AVRs like the Cambridge Audio, and only two or three mappings out of a larger set of six or seven. In any case a good room calibration and correction should take care of the main variables in speaker positions.

Audiosceptics accept audio trials using 25 people. A recent Oxford study with over 353,000 patient records from 639 separate clinical trials shows for every 1,000 people taking diclofenac or ibuprofen there would be 3 additional heart attacks, 4 more cases of heart failure and 1 death every year.

Kilian.ca is offline  
post #94 of 99 Old 01-19-2013, 04:20 PM
AVS Special Member
 
Foxbat121's Avatar
 
Join Date: Jul 2003
Location: VA
Posts: 9,801
Mentioned: 1 Post(s)
Tagged: 0 Thread(s)
Quoted: 107 Post(s)
Liked: 196
You keep mention that old cranky AVR (Onkyo I guess). The thing is technology advanced already. There is no reason to believe that old tale anymore unless you still have that AVR running without burning out smile.gif FYI, my Pioneer Elite 92 is quite old and it has no problem decoding DTS-HD + room correction + other processing.
Foxbat121 is online now  
post #95 of 99 Old 01-19-2013, 05:06 PM
AVS Special Member
 
Kilian.ca's Avatar
 
Join Date: Mar 2007
Location: Ex-50Hz, now 60Hz
Posts: 1,901
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
Liked: 36
Some people buy second hand equipment and not everyone renews their AVR every two or three years. I did make it clear it was a few years ago, in case not everyone is aware of it, for the sake of making a point in a thread like this. I never said the problem still exists. It has nothing to do with technology advance, since it was likely a design fault or idiosyncrasy of equipment rather than a limitation of old technology. I don't see why you have a problem with it.

Audiosceptics accept audio trials using 25 people. A recent Oxford study with over 353,000 patient records from 639 separate clinical trials shows for every 1,000 people taking diclofenac or ibuprofen there would be 3 additional heart attacks, 4 more cases of heart failure and 1 death every year.

Kilian.ca is offline  
post #96 of 99 Old 01-20-2013, 04:42 PM
AVS Special Member
 
David Susilo's Avatar
 
Join Date: Aug 2002
Location: Markham, Canada
Posts: 9,409
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 148 Post(s)
Liked: 329
Wouldn't conversion to PCM is a waste of money then (I assume there is some kind of licensing involved)? My receiver from 5 years ago already have HDMI inputs. How many people still use a receiver from 5 years ago AND care about lossless audio at the same time? Am I the minority here?

follow my A/V tweets @davidsusilo

ISF, THX, CEDIA, Control4 & HAA certified
Reviewer for TED, QAV, AUVI & DownUnder Audio Magazine

my (yet to be completed) BD list
my home theatre

David Susilo is online now  
post #97 of 99 Old 01-21-2013, 12:47 AM
AVS Special Member
 
Kilian.ca's Avatar
 
Join Date: Mar 2007
Location: Ex-50Hz, now 60Hz
Posts: 1,901
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
Liked: 36
You need the licence to 'lift' the stream off the disc and send it and I don't know how much extra it costs to decode to PCM vs. just bitstreaming it. Decoding is built into most SoC now. The chip or licence can't be that much if $100 players now can decode and do a host of other things when manufactured in large volumes.

Apparently the original intention is for the player to decode so it's a waste of money when AVRs duplicate the player's role. Duplication is not only confined to audio decoding, look at video upconversion, video adjustments, streaming, LAN/wi-fi, USB, DAC, flac/mp3/wma/DSD...

Audiosceptics accept audio trials using 25 people. A recent Oxford study with over 353,000 patient records from 639 separate clinical trials shows for every 1,000 people taking diclofenac or ibuprofen there would be 3 additional heart attacks, 4 more cases of heart failure and 1 death every year.

Kilian.ca is offline  
post #98 of 99 Old 01-21-2013, 07:25 AM
AVS Special Member
 
Foxbat121's Avatar
 
Join Date: Jul 2003
Location: VA
Posts: 9,801
Mentioned: 1 Post(s)
Tagged: 0 Thread(s)
Quoted: 107 Post(s)
Liked: 196
Quote:
Originally Posted by Kilian.ca View Post

Some people buy second hand equipment and not everyone renews their AVR every two or three years. I did make it clear it was a few years ago, in case not everyone is aware of it, for the sake of making a point in a thread like this. I never said the problem still exists. It has nothing to do with technology advance, since it was likely a design fault or idiosyncrasy of equipment rather than a limitation of old technology. I don't see why you have a problem with it.
I don't have any problem with it. I just have the problem with this entire discussion. I thought we burried it, e.g. beaten to death of this topic, a few years back.
Foxbat121 is online now  
post #99 of 99 Old 01-22-2013, 01:05 AM
AVS Special Member
 
Kilian.ca's Avatar
 
Join Date: Mar 2007
Location: Ex-50Hz, now 60Hz
Posts: 1,901
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
Liked: 36
A lot of topics are beaten to death on the internet, deal with it or ignore it. How many times have "can't see dts-HD on the AVR front display" threads come up in the AVR forum? I miss pretty much all the Onkyo AVR 'debate', just aware of it, I guess you hang around in the AVR forum too much...biggrin.gif

This 'PCM vs. bitstream' is also beaten to death also, maybe it's time to lock this thread.

Audiosceptics accept audio trials using 25 people. A recent Oxford study with over 353,000 patient records from 639 separate clinical trials shows for every 1,000 people taking diclofenac or ibuprofen there would be 3 additional heart attacks, 4 more cases of heart failure and 1 death every year.

Kilian.ca is offline  
Reply Blu-ray Players

Tags
Sony Bdp S350 Full Hd Blu Ray Disc Dvd Player W Hdmi Lan
Gear in this thread

Thread Tools
Show Printable Version Show Printable Version
Email this Page Email this Page


Forum Jump: 

Posting Rules  
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off