Re: Spatial/Atmos on FLAC?

=?windows-1257?Q?Renatas_Lau=FEadis?= <[email protected]> Tue, 22 Aug 2017 10:58:18 +0000
Newsgroups gmane.comp.audio.compression.flac.user
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Hm,

"Atmos presumably has it's own lossy compression=94 =96 maybe. But what abo=
ut Atmos in TrueHD or Atmos in LPCM?

Spatial audio:
https://developer.microsoft.com/en-us/windows/mixed-reality/spatial_sound
https://developer.microsoft.com/en-us/windows/mixed-reality/spatial_sound_i=
n_directx

There is a set of HRTF functions - head-relative transfer functions
There are basically 3 major formats DTS:X, Atmos and Auro 3D.

One of the major obstacles for VR/AR headsets is the sound and proper posit=
ioning of sound. IMHO, this is one of the reasons why Microsoft is bringing=
 Dolby Atmos to Windows platform. And this is one of the reasons Microsoft =
has implemented Windows Sonic at the same time. There are no popular mechan=
isms to position objects based audio in some kind unified way. Windows Soni=
c is now one such technology.

While Windows Sonic rendering exists there is now format for this kind of f=
iles, except Atmos and DTS:X. Sony does their own implementation.

So I thought maybe FLAC or Xiph.org has some plans for that...

Sent from Mail<https://go.microsoft.com/fwlink/?LinkId=3D550986> for Window=
s 10

From: Brian Willoughby<mailto:[email protected]>
Sent: 2017 m. rugpj=FB=E8io 12 d., =F0e=F0tadienis 12:45
To: [email protected]<mailto:[email protected]>
Subject: Re: [Flac] Spatial/Atmos on FLAC?

On Aug 10, 2017, at 5:46 AM, Renatas Lau?adis <[email protected]> wrote:
> are there any plans for FLAC to implement spatial audio? Or maybe Atmos o=
n FLAC?

FLAC is a multichannel audio format supporting up to 8 channels. There are =
advantages to compressing 2 channel (stereo) audio in terms of file size sa=
vings, but there is no compression advantage to other combinations.

Atmos supports up to 128 channels, 10-channel minimum, so it cannot be dire=
ctly stored in FLAC due to the 8-channel limit. In addition, Atmos presumab=
ly has it's own lossy compression, so it would be pointless to use a lossle=
ss conversion for a lossy surround file. Atmos is also proprietary, or at l=
east I assume we do not have the option of supporting it anyway.

I do not see any documentation of Spatial - is that a standard format? Is i=
t an open format? Is it even intended to be distributed as a separate digit=
al file?

In any event, archival and delivery for mastering of surround audio is gene=
rally done in individual mono files. Some surround projects are delivered o=
n 8-channel digital audio tape with only 6 channels used in the case of 5.1=
 surround audio. Beyond 5.1, there must be various methods of delivering au=
dio. There might be some advantage with FLAC to combine pairs in surround, =
such as front, side, rear, but otherwise I would say that it's a bad idea t=
o try and place more than 2 channels in a single file. The audio frames bec=
ome too large to compress well.

There's a difference between formats used for recording, mixing, and master=
ing versus formats used for delivery of the final product to consumers. Del=
ivery formats like Dolby and DTS generally require licensed software compre=
ssion tools, making it difficult to convert to FLAC in any case.

Perhaps you could explain more about what you hope to see?

Brian Willoughby

_______________________________________________
Flac mailing list
[email protected]
http://lists.xiph.org/mailman/listinfo/flac


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<p class=3D"MsoNormal"><span style=3D"font-family:&quot;Segoe UI&quot;,sans=
-serif">Hm,<o:p></o:p></span></p>
<p class=3D"MsoNormal"><span style=3D"font-family:&quot;Segoe UI&quot;,sans=
-serif"><o:p>&nbsp;</o:p></span></p>
<p class=3D"MsoNormal"><span style=3D"font-size:10.0pt;font-family:&quot;Se=
goe UI&quot;,sans-serif">&quot;Atmos presumably has it's own lossy compress=
ion</span><span lang=3D"EN-US" style=3D"font-size:10.0pt;font-family:&quot;=
Segoe UI&quot;,sans-serif">=94 =96 maybe. But what about Atmos in TrueHD
 or Atmos in LPCM?</span><span lang=3D"EN-US" style=3D"font-family:&quot;Se=
goe UI&quot;,sans-serif"><o:p></o:p></span></p>
<p class=3D"MsoNormal"><span style=3D"font-family:&quot;Segoe UI&quot;,sans=
-serif"><o:p>&nbsp;</o:p></span></p>
<p class=3D"MsoNormal"><span style=3D"font-family:&quot;Segoe UI&quot;,sans=
-serif">Spatial audio:<o:p></o:p></span></p>
<p class=3D"MsoNormal"><span style=3D"font-family:&quot;Segoe UI&quot;,sans=
-serif"><a href=3D"https://developer.microsoft.com/en-us/windows/mixed-real=
ity/spatial_sound">https://developer.microsoft.com/en-us/windows/mixed-real=
ity/spatial_sound</a>
<o:p></o:p></span></p>
<p class=3D"MsoNormal"><span style=3D"font-family:&quot;Segoe UI&quot;,sans=
-serif"><a href=3D"https://developer.microsoft.com/en-us/windows/mixed-real=
ity/spatial_sound_in_directx">https://developer.microsoft.com/en-us/windows=
/mixed-reality/spatial_sound_in_directx</a>
<o:p></o:p></span></p>
<p class=3D"MsoNormal"><span style=3D"font-family:&quot;Segoe UI&quot;,sans=
-serif"><o:p>&nbsp;</o:p></span></p>
<p class=3D"MsoNormal"><span style=3D"font-family:&quot;Segoe UI&quot;,sans=
-serif">There is a set of HRTF functions -
</span><span lang=3D"EN" style=3D"font-family:&quot;Segoe UI&quot;,sans-ser=
if">head-relative transfer functions</span><span style=3D"font-family:&quot=
;Segoe UI&quot;,sans-serif"><o:p></o:p></span></p>
<p class=3D"MsoNormal"><span style=3D"font-family:&quot;Segoe UI&quot;,sans=
-serif">There are basically 3 major formats DTS:X, Atmos and Auro 3D.<o:p><=
/o:p></span></p>
<p class=3D"MsoNormal"><span style=3D"font-family:&quot;Segoe UI&quot;,sans=
-serif"><o:p>&nbsp;</o:p></span></p>
<p class=3D"MsoNormal"><span style=3D"font-family:&quot;Segoe UI&quot;,sans=
-serif">One of the major obstacles for VR/AR headsets is the sound and prop=
er positioning of sound. IMHO, this is one of the reasons why Microsoft is =
bringing Dolby Atmos to Windows platform. And
 this is one of the reasons Microsoft has implemented Windows Sonic at the =
same time. There are no popular mechanisms to position objects based audio =
in some kind unified way. Windows Sonic is now one such technology.<o:p></o=
:p></span></p>
<p class=3D"MsoNormal"><span style=3D"font-family:&quot;Segoe UI&quot;,sans=
-serif"><o:p>&nbsp;</o:p></span></p>
<p class=3D"MsoNormal"><span style=3D"font-family:&quot;Segoe UI&quot;,sans=
-serif">While Windows Sonic rendering exists there is now format for this k=
ind of files, except Atmos and DTS:X. Sony does their own implementation.<o=
:p></o:p></span></p>
<p class=3D"MsoNormal"><span style=3D"font-family:&quot;Segoe UI&quot;,sans=
-serif"><o:p>&nbsp;</o:p></span></p>
<p class=3D"MsoNormal"><span style=3D"font-family:&quot;Segoe UI&quot;,sans=
-serif">So I thought maybe FLAC or Xiph.org has some plans for that...<o:p>=
</o:p></span></p>
<p class=3D"MsoNormal"><o:p>&nbsp;</o:p></p>
<p class=3D"MsoNormal">Sent from <a href=3D"https://go.microsoft.com/fwlink=
/?LinkId=3D550986">
Mail</a> for Windows 10</p>
<p class=3D"MsoNormal"><o:p>&nbsp;</o:p></p>
<div style=3D"mso-element:para-border-div;border:none;border-top:solid #E1E=
1E1 1.0pt;padding:3.0pt 0cm 0cm 0cm">
<p class=3D"MsoNormal" style=3D"border:none;padding:0cm"><b>From: </b><a hr=
ef=3D"mailto:[email protected]">Brian Willoughby</a><br>
<b>Sent: </b>2017 m. rugpj=FB=E8io 12 d., =F0e=F0tadienis 12:45<br>
<b>To: </b><a href=3D"mailto:[email protected]">[email protected]</a><br>
<b>Subject: </b>Re: [Flac] Spatial/Atmos on FLAC?</p>
</div>
<p class=3D"MsoNormal"><o:p>&nbsp;</o:p></p>
<p class=3D"MsoNormal"><span style=3D"font-size:10.0pt">On Aug 10, 2017, at=
 5:46 AM, Renatas Lau?adis &lt;[email protected]&gt; wrote:<br>
&gt; are there any plans for FLAC to implement spatial audio? Or maybe Atmo=
s on FLAC?<br>
<br>
FLAC is a multichannel audio format supporting up to 8 channels. There are =
advantages to compressing 2 channel (stereo) audio in terms of file size sa=
vings, but there is no compression advantage to other combinations.<br>
<br>
Atmos supports up to 128 channels, 10-channel minimum, so it cannot be dire=
ctly stored in FLAC due to the 8-channel limit. In addition, Atmos presumab=
ly has it's own lossy compression, so it would be pointless to use a lossle=
ss conversion for a lossy surround
 file. Atmos is also proprietary, or at least I assume we do not have the o=
ption of supporting it anyway.<br>
<br>
I do not see any documentation of Spatial - is that a standard format? Is i=
t an open format? Is it even intended to be distributed as a separate digit=
al file?<br>
<br>
In any event, archival and delivery for mastering of surround audio is gene=
rally done in individual mono files. Some surround projects are delivered o=
n 8-channel digital audio tape with only 6 channels used in the case of 5.1=
 surround audio. Beyond 5.1, there
 must be various methods of delivering audio. There might be some advantage=
 with FLAC to combine pairs in surround, such as front, side, rear, but oth=
erwise I would say that it's a bad idea to try and place more than 2 channe=
ls in a single file. The audio frames
 become too large to compress well.<br>
<br>
There's a difference between formats used for recording, mixing, and master=
ing versus formats used for delivery of the final product to consumers. Del=
ivery formats like Dolby and DTS generally require licensed software compre=
ssion tools, making it difficult
 to convert to FLAC in any case.<br>
<br>
Perhaps you could explain more about what you hope to see?<br>
<br>
Brian Willoughby<br>
<br>
_______________________________________________<br>
Flac mailing list<br>
[email protected]<br>
<a href=3D"http://lists.xiph.org/mailman/listinfo/flac">http://lists.xiph.o=
rg/mailman/listinfo/flac</a><o:p></o:p></span></p>
<p class=3D"MsoNormal"><o:p>&nbsp;</o:p></p>
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