Player audio options - bitstream or PCM?

Okay, that's slightly better news.
So what happens if you have dts to tv, such as a networked file or disc? Does the tv pass it on to the amp as 2ch pcm? Coz that's a fairly standard phenomenon anyway.
Surely it wouldn't just end up as silence - tv end?
I believe you are buggered.
 

goingoingong

Distinguished Member
Okay, that's slightly better news.
So what happens if you have dts to tv, such as a networked file or disc? Does the tv pass it on to the amp as 2ch pcm? Coz that's a fairly standard phenomenon anyway.
Surely it wouldn't just end up as silence - tv end?
It will end up the same as Panasonic playing HD audio on .mkv files, The Sound of Silence....
AFAIK the TV's don't have DTS decoders so can't pass on anything as they can't decode it.

Cost cutting as they'd otherwise have to pay DTS a licence fee.
 

IvanFraser

Member
Does anyone know why most blurays and dvds downsample higher res LPCM audio - usually 96kh - to 48Khz via coax output to dac?
If this is a standard spec, how come I have at least 1 lpcm 96khz dvd that outputs as native 96khz to my dac?
I had accepted what I had managed to ascertain by Googling why output was at 48khz. I got the impression that this was a standard thing.
So when I saw 96khz on a lpcm stereo via coax on my dac the other day, it really surprised me. Having changed nothing on my setup, and the disc spec was the same as other lpcm stereo dvds I have, I am left confused as to why it will play directly in 96khz when most others will not.
96khz is output if over HDMI to the av amp, but usually downsamples to 48khz if played to the dac over coax.
It's the ub900 coax out to Audiolab 8300cd.
 

Manmc

Member
Uncompressed 96khz over coax is limited to 2-ch you need HDMI to send more channels like 5.1/7.1 full rate . There is an Audio Down Sampling setting on the ub-900 which , if set to 48khz , would down-convert your 96khz pcm .

~M~
 

IvanFraser

Member
Uncompressed 96khz over coax is limited to 2-ch you need HDMI to send more channels like 5.1/7.1 full rate . There is an Audio Down Sampling setting on the ub-900 which , if set to 48khz , would down-convert your 96khz pcm .

~M~
Thanks, but I already know that.
What I'm confused about is why most of my stereo pcm discs are outputting at 48khz over coax, and then one (at least) plays the same format as 96khz.
I don't downsample at the player as my avr will take up to 192 afaik. It plays 96 no problem.
So why the difference over coax when coax can take 96khz?
 

IvanFraser

Member
oh, and contrary to what you said above - which makes it even more confusing - the remaster applied at the player for the same track via coax was registered at the dac as 192khz!
Whereas on the other discs the remaster setting has no effect - it stays at 48khz.
 
The vast majority of DVDs output 48Khz. Although 96Khz is technically possible, the higher sample rate requires a reduction in video quality due to the limited bandwidth of DVDs, hence the prevalence of 48Khz audio.

Blu ray discs obviously have much more bandwidth, and are therefore not similarly restricted.
 

IvanFraser

Member
The vast majority of DVDs output 48Khz. Although 96Khz is technically possible, the higher sample rate requires a reduction in video quality due to the limited bandwidth of DVDs, hence the prevalence of 48Khz audio.

Blu ray discs obviously have much more bandwidth, and are therefore not similarly restricted.
I'm now playing the DVD stereo LPCM version of Yes Relayer album. My player is registering it as 96khz over coax.
If I apply remaster, it registers as 192, and it clearly has a different sound.
Prior to that I played the new Jethro Tull A remaster album DVD - also 96khz - also stereo lpcm, and it will not play as anything other than 48Khz over coax, remaster at the player or not.
Anybody have any ideas why?
 
I'm now playing the DVD stereo LPCM version of Yes Relayer album. My player is registering it as 96khz over coax.
If I apply remaster, it registers as 192, and it clearly has a different sound.
Prior to that I played the new Jethro Tull A remaster album DVD - also 96khz - also stereo lpcm, and it will not play as anything other than 48Khz over coax, remaster at the player or not.
Anybody have any ideas why?
If you listen to Yes and Jethro Tull, you are fortunate that your DVD player even plays them - it should be made illegal.
 

IvanFraser

Member
If you listen to Yes and Jethro Tull, you are fortunate that your DVD player even plays them - it should be made illegal.
So says one of the guitarists in my old band, and yet the other guitarist is of the opposite opinion :
Guess which one is the classically trained musician?
 

IvanFraser

Member
I've got a theory.
Maybe the one that plays at 96Hz is recorded in 16 bit, whilst all the rest are at 24, so restrictions maybe applied according to bitrate and not frequency?
I notice though that all the 48 restricted discs will show 48 as hdmi output if coax is engaged. This is echoed by the dac showing 48 also. But put to hdmi only will show 96.
However, on this Relayer, the hdmi output has also switched to 48, whereas the coax is outputting 96!
Switch back to hdmi only and it shows 96 again.
And this disc does not specify what bitrate it uses.
 

Steve356

Distinguished Member
I've got a theory.
Maybe the one that plays at 96Hz is recorded in 16 bit, whilst all the rest are at 24, so restrictions maybe applied according to bitrate and not frequency?
I notice though that all the 48 restricted discs will show 48 as hdmi output if coax is engaged. This is echoed by the dac showing 48 also. But put to hdmi only will show 96.
However, on this Relayer, the hdmi output has also switched to 48, whereas the coax is outputting 96!
Switch back to hdmi only and it shows 96 again.
And this disc does not specify what bitrate it uses.

What do the specs claim for those individual soundtracks on the DVDs?
 

IvanFraser

Member
What do the specs claim for those individual soundtracks on the DVDs?
I've just checked the playback info, so my 24bit theory is out the window.

The Relayer - which sends 96, 192 etc. - just says LPCM as an audio option in the menu. The playback info says lpcm 96khz/24b.
And that's exactly what all the other discs state in the playback info, and yet will only output 48 over coax.
 

Steve356

Distinguished Member
I've just checked the playback info, so my 24bit theory is out the window.

The Relayer - which sends 96, 192 etc. - just says LPCM as an audio option in the menu. The playback info says lpcm 96khz/24b.
And that's exactly what all the other discs state in the playback info, and yet will only output 48 over coax.

Does seem odd. I don't have either of those titles so can't test it out on my system unfortunately.
 
So says one of the guitarists in my old band, and yet the other guitarist is of the opposite opinion :
Guess which one is the classically trained musician?
Rick Wakeman was a classically trained musician. It's not necessarily a mark of good taste.
 

IvanFraser

Member
Does seem odd. I don't have either of those titles so can't test it out on my system unfortunately.
I think the Relayer is the exception, because - when I've looked - the rest seem to be limited to 48.
I could be wrong, as I don't usually look at the dac's display. There may be others that behave in the same way.
 

IvanFraser

Member
In my UB420 and UB820 I also prefer convert dts to pcm, panas also have nice option to boost dialog volume.
On my avr it will state Dolby True HD when that is playing, with the movie dsp engaged.
However, DTSHDMA is only displayed when the dsp is off. So I'm guessing that when I play a br with DTSHDMA, the amp is perhaps not giving me the HDMA. And yet, the player tells me it is outputting it.
I'm guessing the dts-pcm conversion is outputting the full hdma as lossless over pcm.
Like I said earlier, I cannot commit to a preference, I just note a slight 'difference'.
Perhaps the nod might go to the pcm version, because I did notice more detail (a deeper more realistic bass drum sound) when pcm was output. But I can't swear that it wasn't supposed to sound 'worse' :0)
 

bl4ck

Member
Big change after set DTS > PCM is sound from surr speakers more details and db.
 
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gibbsy

Moderator
On my avr it will state Dolby True HD when that is playing, with the movie dsp engaged.
However, DTSHDMA is only displayed when the dsp is off. So I'm guessing that when I play a br with DTSHDMA, the amp is perhaps not giving me the HDMA. And yet, the player tells me it is outputting it.
I'm guessing the dts-pcm conversion is outputting the full hdma as lossless over pcm.
Like I said earlier, I cannot commit to a preference, I just note a slight 'difference'.
Perhaps the nod might go to the pcm version, because I did notice more detail (a deeper more realistic bass drum sound) when pcm was output. But I can't swear that it wasn't supposed to sound 'worse' :0)
All my Dolby TrueHD, along with Atmos titles concert discs are downmixed to 48hz. I believe, happy to be proved wrong, that it's a copyright issue involving HDCP.
 

IvanFraser

Member
All my Dolby TrueHD, along with Atmos titles concert discs are downmixed to 48hz. I believe, happy to be proved wrong, that it's a copyright issue involving HDCP.
If that's the case, then it's presumably engaged disc-side, if it can be defeated.
Relayer came out in 2014. Could that explain it?
Discs prior to this HDCP copyright thing will play in full spectrum as encoded on the disc?
 

IvanFraser

Member
Big change after set DTS > PCM is sound from surr speakers more details and db.
The 5.1 DTS is converted to 7.1 pcm. That probably has a marked effect, and probably explains the differences I hear when I've done so.
Most of my approach is to preserve accuracy, so sticking with DTS 5.1 as 5.1 will most likely ensure greater accuracy than changing to 7.1 PCM, even if the conversion results in a lossless pcm. I only have 5.1, so it needs to be remuxed at the end anyway. The fewer changes to the original as possible usually results in the most accurate output at the end of the chain.
I might feel different if I had a 7.1 setup.
 

IvanFraser

Member
It is looking like the HDCP 2.2 spec is what is limiting 96khz material to 48 over coax.
The one I know that is old - Relayer - probably doesn't have the coding, being 2014.
I have ascertained that the later ones do indeed trigger the 96Khz signal over coax. It jumps up from 48 to 96 on the dac.
However, that's only whilst playing to hdmi.
Once I switch the hdmi off for that track and start getting audio from the coax, it switches down to 48.
It doesn't switch back to 96 when I reverse the process and engage the hdmi audio again. But it does output 96 over the hdmi.

So, not happy that our audio is being restricted. I buy high res dvds and blus partially for the hires audio over coax to my dac. What I'm getting is a downsampled 48Khz version of a 96Khz track.
However, whatever loss there is shouldn't be too noticeable - I hope.
I also am hoping that the analogue stereo to my headphone dac isn't loosing anything. It sounds great to my ears as it is.
 

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