Bitstream or PCM? - Page 4

Way to revive the almost 4-year old thread

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.

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.

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.

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.

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.

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.

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 FYI, my Pioneer Elite 92 is quite old and it has no problem decoding DTS-HD + room correction + other processing.

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.

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?

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...

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.

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...

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