Re: [Sursound] Never do electronic in public.

[Bo-Erik Sandholm]

Standard aliexpress Bluetooth module v2.0+edr have a data rate of 2.1 Mbit/s
It is not so bad if you can get the sensors UART to push data near that
speed.

- Bo-Erik
On 1 Feb 2016 20:33, "David McGriffy" <da...@mcgriffy.com> wrote:

> Right, 10DOF is with altitude. I'm building a drone controller out of piece
> parts as a demonstration.
>
> Yes, there are certainly ways to achieve low latency convolution, but all
> at the expense of CPU, which is already at a premium when running on
> phones.
>
> I first heard the 20ms figure from some folks working in the VR biz.
> Admittedly, they are more camera and content producers and not headset
> makers, so perhaps this is just a dream goal of theirs. It does make some
> sense to me as that's 50Hz, or the same as some TV refresh rates. Being one
> frame off there can certainly be noticeable, especially with speech vs
> moving lips.
>
> It does seem quite reasonable to me that an audio only app would not be as
> critical. And, of course, the video and audio frame rates don't really
> match anyway, or we'd be getting 882 or 960 sample blocks instead of 128 or
> 512.
>
> I got a GearVR recently and it does work better than Google Cardboard. Much
> of this is just comfort, I think, but I understand that it has its own
> gyros, mostly because they are faster. 'Heresay' is that the Oculus Rift
> samples at least 1000Hz. I have actually written an audio rate rotate that
> could handle this, but it does seem like overkill. At normal head turning
> rates, I find interpolating the rotation within each block to be enough.
>
> Any modern gyro and processor will run fast enough. My little 8-bit
> controllers run their complete flight control loop in under 2ms. The limit
> on update rate, and latency for that matter, will be the wireless link.
> Wifi will be fastest but highest power. Bluetooth lower power but lower
> bandwidth and still wireless. Wired would not only be very fast but could
> provide power.
>
> If you are thinking wireless headphones, remember the latency that that
> introduces. I find my everyday bluetooth headset, built for music, is
> useless for VR because of latency. And if you headphones are going to be
> wired, then running that extra USB might not be too bad.
>
> David McGriffy
>
>
> On Mon, Feb 1, 2016 at 12:49 PM, Bo-Erik Sandholm <bosses...@gmail.com>
> wrote:
>
> > Apperently there exists a head tracking specialized version of the bno055
> > called bno070 - but I cannot find a place to buy this.
> > you can get up to 250 samples / second from that version.
> >
> > Matthias did not complain about the update rate with the DIY headtracker
> > http://www.rcgroups.com/forums/showthread.php?t=1677559
> >
> >
> >
> http://electronicspurchasingstrategies.com/2014/03/06/hillcrest-bosch-sensortec-collaborate-sensor-hub-solution/
> >
> > http://docsfiles.com/pdf_bno070.html
> >
> >
> >
> http://ae-bst.resource.bosch.com/media/_tech/media/product_flyer/Mobile-Hillcrest-Labs-Sensor-Hub-Product-Brief-BNO0701.pdf
> >
> >
> >
> https://www.eiseverywhere.com/file_uploads/5c881a2f6eaaa90ed3f3d30fb20852db_Newsflash_BNO077.pdf
> >
> >
> > maybe it is better to not think about that and try and use what I have ?
> >
> > It is easy to find videos about using the bno055 in different projects
> but
> > i do not want videos... have not found links to the software used...
> >
> >
> >
> > Better luck when google github bno055 :-)
> >
> >
> >
> https://www.reddit.com/r/virtualreality/comments/3faq11/why_we_need_to_move_to_ambisonic_sound_in_the/
> >
> > http://vriscoming.com/daydream-vr/
> >
> > Bo-Erik
> >
> > 2016-02-01 18:56 GMT+01:00 Marc Lavallee <m...@hacklava.net>:
> >
> > > On Mon, 01 Feb 2016 17:46:47 +
> > > Stefan Schreiber <st...@mail.telepac.pt> wrote:
> > > > What is a 10 DOF motion sensor??? (Didn't you mean 9DOF?)
> > >
> > > It's 9DOF + barometric pressure, so 9DOF is enough. For more info:
> > >
> >
> http://playground.arduino.cc/Main/WhatIsDegreesOfFreedom6DOF9DOF10DOF11DOF
> > >
> > > --
> > > Marc
> > > ___
> > > Sursound mailing list
> > > Sursound@music.vt.edu
> > > https://mail.music.vt.edu/mailman/listinfo/sursound - unsubscribe
> here,
> > > edit account or options, view archives and so on.
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Re: [Sursound] Never do electronic in public.

[Stefan Schreiber]

Stefan Schreiber wrote:


David McGriffy wrote:



I got a GearVR recently and it does work better than Google 
Cardboard. Much

of this is just comfort, I think, but I understand that it has its own
gyros, mostly because they are faster. 'Heresay' is that the Oculus Rift
samples at least 1000Hz.


Yes, but do you need this?

The Rift is scheduled for release on March 28, 2016, making it one of 
the first consumer-targeted virtual reality headsets. It has a 
resolution of 1080×1200 per eye, a 90 Hz refresh rate, and a wide 
field of view.



https://en.wikipedia.org/wiki/Oculus_Rift

I see an issue if an assumed 125 Hz or 250 Hz sensor is not synced to 
90 Hz, because this will lead to different "phases" brought into a 
non-fractional pattern. The problem then is that the 90Hz impression 
will be not be really smooth, in this case (A kind of 3:2 pulldown 
effect, so to speak. Different time lengths in 90 uneven parts, old 
story.)


You don't have to sync sensor and screen update speeds  if you have a 
very high sensor speed.


And if I think about a bit further:

The video frames (75 to 120 Hz refresh rate) should be built up 
according "current" positional and view directional data.


The audio case is a bit different, IMO. Audio synthesis (VR/AR) has to 
be aligned with the video data, but the "colour changes" introduced by 
head orientation are very probably less time-sensitive. (s. available 
studies I have cited.)


Does this make sense?

Stefan






If you are thinking wireless headphones, remember the latency that that
introduces. I find my everyday bluetooth headset, built for music, is
useless for VR because of latency.


You don't need (absolute) real-time capability to listen to a recording.

Tracking needs RT response.

Best,

Stefan


And if you headphones are going to be
wired, then running that extra USB might not be too bad.

David McGriffy


On Mon, Feb 1, 2016 at 12:49 PM, Bo-Erik Sandholm <bosses...@gmail.com>
wrote:

 

Apperently there exists a head tracking specialized version of the 
bno055

called bno070 - but I cannot find a place to buy this.
you can get up to 250 samples / second from that version.

Matthias did not complain about the update rate with the DIY 
headtracker

http://www.rcgroups.com/forums/showthread.php?t=1677559


http://electronicspurchasingstrategies.com/2014/03/06/hillcrest-bosch-sensortec-collaborate-sensor-hub-solution/ 



http://docsfiles.com/pdf_bno070.html


http://ae-bst.resource.bosch.com/media/_tech/media/product_flyer/Mobile-Hillcrest-Labs-Sensor-Hub-Product-Brief-BNO0701.pdf 




https://www.eiseverywhere.com/file_uploads/5c881a2f6eaaa90ed3f3d30fb20852db_Newsflash_BNO077.pdf 




maybe it is better to not think about that and try and use what I 
have ?


It is easy to find videos about using the bno055 in different 
projects but

i do not want videos... have not found links to the software used...



Better luck when google github bno055 :-)


https://www.reddit.com/r/virtualreality/comments/3faq11/why_we_need_to_move_to_ambisonic_sound_in_the/ 



http://vriscoming.com/daydream-vr/

Bo-Erik

2016-02-01 18:56 GMT+01:00 Marc Lavallee <m...@hacklava.net>:

  


On Mon, 01 Feb 2016 17:46:47 +
Stefan Schreiber <st...@mail.telepac.pt> wrote:



What is a 10 DOF motion sensor??? (Didn't you mean 9DOF?)
  


It's 9DOF + barometric pressure, so 9DOF is enough. For more info:




http://playground.arduino.cc/Main/WhatIsDegreesOfFreedom6DOF9DOF10DOF11DOF 

  


--
Marc
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Re: [Sursound] Never do electronic in public.

[Stefan Schreiber]

David McGriffy wrote:



I got a GearVR recently and it does work better than Google Cardboard. Much
of this is just comfort, I think, but I understand that it has its own
gyros, mostly because they are faster. 'Heresay' is that the Oculus Rift
samples at least 1000Hz.


Yes, but do you need this?

The Rift is scheduled for release on March 28, 2016, making it one of 
the first consumer-targeted virtual reality headsets. It has a 
resolution of 1080×1200 per eye, a 90 Hz refresh rate, and a wide 
field of view.


https://en.wikipedia.org/wiki/Oculus_Rift

I see an issue if an assumed 125 Hz or 250 Hz sensor is not synced to 90 
Hz, because this will lead to different "phases" brought into a 
non-fractional pattern. The problem then is that the 90Hz impression 
will be not be really smooth, in this case (A kind of 3:2 pulldown 
effect, so to speak. Different time lengths in 90 uneven parts, old story.)


You don't have to sync sensor and screen update speeds  if you have a 
very high sensor speed.





If you are thinking wireless headphones, remember the latency that that
introduces. I find my everyday bluetooth headset, built for music, is
useless for VR because of latency. 


You don't need (absolute) real-time capability to listen to a recording.

Tracking needs RT response.

Best,

Stefan


And if you headphones are going to be
wired, then running that extra USB might not be too bad.

David McGriffy


On Mon, Feb 1, 2016 at 12:49 PM, Bo-Erik Sandholm <bosses...@gmail.com>
wrote:

 


Apperently there exists a head tracking specialized version of the bno055
called bno070 - but I cannot find a place to buy this.
you can get up to 250 samples / second from that version.

Matthias did not complain about the update rate with the DIY headtracker
http://www.rcgroups.com/forums/showthread.php?t=1677559


http://electronicspurchasingstrategies.com/2014/03/06/hillcrest-bosch-sensortec-collaborate-sensor-hub-solution/

http://docsfiles.com/pdf_bno070.html


http://ae-bst.resource.bosch.com/media/_tech/media/product_flyer/Mobile-Hillcrest-Labs-Sensor-Hub-Product-Brief-BNO0701.pdf


https://www.eiseverywhere.com/file_uploads/5c881a2f6eaaa90ed3f3d30fb20852db_Newsflash_BNO077.pdf


maybe it is better to not think about that and try and use what I have ?

It is easy to find videos about using the bno055 in different projects but
i do not want videos... have not found links to the software used...



Better luck when google github bno055 :-)


https://www.reddit.com/r/virtualreality/comments/3faq11/why_we_need_to_move_to_ambisonic_sound_in_the/

http://vriscoming.com/daydream-vr/

Bo-Erik

2016-02-01 18:56 GMT+01:00 Marc Lavallee <m...@hacklava.net>:

   


On Mon, 01 Feb 2016 17:46:47 +
Stefan Schreiber <st...@mail.telepac.pt> wrote:
 


What is a 10 DOF motion sensor??? (Didn't you mean 9DOF?)
   


It's 9DOF + barometric pressure, so 9DOF is enough. For more info:

 


http://playground.arduino.cc/Main/WhatIsDegreesOfFreedom6DOF9DOF10DOF11DOF
   


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Re: [Sursound] Never do electronic in public.

[Bo-Erik Sandholm]

http://hackaday.com/2016/02/01/ftdi-drivers-break-fake-chips-again/
In the near future serial over USB with windows might be flaky.

Bo-Erik
On 1 Feb 2016 21:53, "Bo-Erik Sandholm" <bosses...@gmail.com> wrote:

> Standard aliexpress Bluetooth module v2.0+edr have a data rate of 2.1
> Mbit/s
> It is not so bad if you can get the sensors UART to push data near that
> speed.
>
> - Bo-Erik
> On 1 Feb 2016 20:33, "David McGriffy" <da...@mcgriffy.com> wrote:
>
>> Right, 10DOF is with altitude. I'm building a drone controller out of
>> piece
>> parts as a demonstration.
>>
>> Yes, there are certainly ways to achieve low latency convolution, but all
>> at the expense of CPU, which is already at a premium when running on
>> phones.
>>
>> I first heard the 20ms figure from some folks working in the VR biz.
>> Admittedly, they are more camera and content producers and not headset
>> makers, so perhaps this is just a dream goal of theirs. It does make some
>> sense to me as that's 50Hz, or the same as some TV refresh rates. Being
>> one
>> frame off there can certainly be noticeable, especially with speech vs
>> moving lips.
>>
>> It does seem quite reasonable to me that an audio only app would not be as
>> critical. And, of course, the video and audio frame rates don't really
>> match anyway, or we'd be getting 882 or 960 sample blocks instead of 128
>> or
>> 512.
>>
>> I got a GearVR recently and it does work better than Google Cardboard.
>> Much
>> of this is just comfort, I think, but I understand that it has its own
>> gyros, mostly because they are faster. 'Heresay' is that the Oculus Rift
>> samples at least 1000Hz. I have actually written an audio rate rotate that
>> could handle this, but it does seem like overkill. At normal head turning
>> rates, I find interpolating the rotation within each block to be enough.
>>
>> Any modern gyro and processor will run fast enough. My little 8-bit
>> controllers run their complete flight control loop in under 2ms. The limit
>> on update rate, and latency for that matter, will be the wireless link.
>> Wifi will be fastest but highest power. Bluetooth lower power but lower
>> bandwidth and still wireless. Wired would not only be very fast but could
>> provide power.
>>
>> If you are thinking wireless headphones, remember the latency that that
>> introduces. I find my everyday bluetooth headset, built for music, is
>> useless for VR because of latency. And if you headphones are going to be
>> wired, then running that extra USB might not be too bad.
>>
>> David McGriffy
>>
>>
>> On Mon, Feb 1, 2016 at 12:49 PM, Bo-Erik Sandholm <bosses...@gmail.com>
>> wrote:
>>
>> > Apperently there exists a head tracking specialized version of the
>> bno055
>> > called bno070 - but I cannot find a place to buy this.
>> > you can get up to 250 samples / second from that version.
>> >
>> > Matthias did not complain about the update rate with the DIY headtracker
>> > http://www.rcgroups.com/forums/showthread.php?t=1677559
>> >
>> >
>> >
>> http://electronicspurchasingstrategies.com/2014/03/06/hillcrest-bosch-sensortec-collaborate-sensor-hub-solution/
>> >
>> > http://docsfiles.com/pdf_bno070.html
>> >
>> >
>> >
>> http://ae-bst.resource.bosch.com/media/_tech/media/product_flyer/Mobile-Hillcrest-Labs-Sensor-Hub-Product-Brief-BNO0701.pdf
>> >
>> >
>> >
>> https://www.eiseverywhere.com/file_uploads/5c881a2f6eaaa90ed3f3d30fb20852db_Newsflash_BNO077.pdf
>> >
>> >
>> > maybe it is better to not think about that and try and use what I have ?
>> >
>> > It is easy to find videos about using the bno055 in different projects
>> but
>> > i do not want videos... have not found links to the software used...
>> >
>> >
>> >
>> > Better luck when google github bno055 :-)
>> >
>> >
>> >
>> https://www.reddit.com/r/virtualreality/comments/3faq11/why_we_need_to_move_to_ambisonic_sound_in_the/
>> >
>> > http://vriscoming.com/daydream-vr/
>> >
>> > Bo-Erik
>> >
>> > 2016-02-01 18:56 GMT+01:00 Marc Lavallee <m...@hacklava.net>:
>> >
>> > > On Mon, 01 Feb 2016 17:46:47 +
>> > > Stefan Schreiber <st...@mail.telepac.pt> wrote:
>> > > > What is a 10 DOF motion sensor??? (Didn't you mean 9DOF?)
>> > >
>> > > It's 9DOF + barometric 

Re: [Sursound] Never do electronic in public.

[Stefan Schreiber]

David McGriffy wrote:



I got a GearVR recently and it does work better than Google Cardboard. Much
of this is just comfort, I think, but I understand that it has its own
gyros, mostly because they are faster. 'Heresay' is that the Oculus Rift
samples at least 1000Hz. I have actually written an audio rate rotate that
could handle this, but it does seem like overkill. At normal head turning
rates, I find interpolating the rotation within each block to be enough.

 


http://blogs.valvesoftware.com/abrash/latency-the-sine-qua-non-of-ar-and-vr/

(Written by a super-expert of VR)

Assuming accurate, consistent tracking (and that’s a big if, as I’ll 
explain one of these days), the enemy of virtual registration is 
latency. < If too much time elapses between the time your head starts 
to turn and the time the image is redrawn to account for the new pose, 
the virtual image will drift far enough so that it has clearly wobbled 
(in VR), or so that is obviously no longer aligned with the same 
real-world features (in AR). >


(Elaboration:)

Suppose you rotate your head at 60 degrees/second. That sounds fast, 
but in fact it’s just a slow turn; you are capable of moving your head 
at hundreds of degrees/second. Also suppose that latency is 50 ms and 
resolution is 1K x 1K over a 100-degree FOV. Then as your head turns, 
the virtual images being displayed are based on 50 ms-old data, which 
means that their positions are off by three degrees, which is wider 
than your thumb held at arm’s length. Put another way, the object 
positions are wrong by 30 pixels. Either way, the error is very 
noticeable.



In other words: There are speed/delay problems, there are sync problems, 
there might be more...



You can do prediction to move the drawing position to the right place, 
and that works pretty well most of the time. Unfortunately, when there 
is a sudden change of direction, the error becomes even bigger than 
with no prediction. 



Tracking latency is highly dependent on the system used. An IMU (3-DOF 
gyro and 3-DOF accelerometer) has very low latency – on the order of 1 
ms – but drifts. < In particular, position derived from the 
accelerometer drifts badly, because it’s derived via double 
integration from acceleration. > Camera-based tracking doesn’t drift, 
but has high latency due to the need to capture the image, transfer it 
to the computer, and process the image to determine the pose; that can 
easily take 10-15 ms. < Right now, one of the lowest-latency 
non-drifting accurate systems out there is a high-end system from NDI, 
which has about 4 ms of latency, so we’ll use that for the tracking 
latency. >




It would be far easier and more generally applicable to have the 
display run at 120 Hz, which would immediately reduce display latency 
to about 8 ms, bringing total latency down to 12-14 ms.


(s. PlaystationVR...)

If you ever thought that AR/VR was just a simple matter of showing an 
image on the inside of glasses or goggles, I hope that by this point 
in the blog it’s become clear just how complex and subtle it is to 
present convincing virtual images – and we’ve only scratched the surface. 



Wise words... (No, really!)

But not to get stuck and despair: Motion-tracked audio seems to be 
so much easier to realize...



Best regards,

Stefan









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Re: [Sursound] Never do electronic in public.

[Marc Lavallée]

Le Mon, 1 Feb 2016 22:01:26 +0100,
Bo-Erik Sandholm  a écrit :

> http://hackaday.com/2016/02/01/ftdi-drivers-break-fake-chips-again/
> In the near future serial over USB with windows might be flaky.

That may be another reason to go wireless...

A new chip, the esp32 (still in beta) is an upgrade of the esp8266,
with two processors, wifi, bluetooth, extras gpios and a i2s interface
(for audio), but with no usb (by design, because wireless is the future:

http://esp32.de/

--
Marc

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Re: [Sursound] Never do electronic in public.

[Michael Chapman]

> I just looked back at sursound mails and michael chapman had pointed out
> that the teensy has four channel audio support. >
> http://www.pjrc.com/teensy/td_libs_Audio.html
>
> umashankar
>
>
Must refuse the credit.
I just participated in that thread.

Michael

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Re: [Sursound] Never do electronic in public.

[umashankar manthravadi]

I just looked back at sursound mails and michael chapman had pointed out that 
the teensy has four channel audio support. > 
http://www.pjrc.com/teensy/td_libs_Audio.html

umashankar

Sent from Mail<https://go.microsoft.com/fwlink/?LinkId=550986> for Windows 10

From: Bo-Erik Sandholm<mailto:bosses...@gmail.com>
Sent: Monday, February 1, 2016 1:12 PM
To: sursound<mailto:sursound@music.vt.edu>
Cc: umashankar mantravadi<mailto:umasha...@hotmail.com>; Stefan 
Schreiber<mailto:st...@mail.telepac.pt>; Marc Lavallée<mailto:m...@hacklava.net>
Subject: Re: [Sursound] Never do electronic in public.

I am not really very structured and gets distracted easily, in this
experiment the final hardware setup is not decided, currently my software
structure thinking is like this.

OSC for the protocol as most available Ambisonics sw is VST's for PC or Mac
and Reaper accepts OSC for controls. If done right OSC does not have a
latency problem. Just remember the speed of data output from the sensor
needs to be set high :-)

Reaper is because I am currently thinking of the binaural conversion
experiments with Ambisonics, there do exist 4 channel vst player software's
more like normal apps when the playback chain is configured for end users.

Or would it be better to use oculus rift syntax for the position messages
to be compatible with VR apps?
Or maybe make it changeable by just loading different software?
With my current WiFi plan maybe the wifi chip should accept oculus syntax
and convert and send OSC to be flexible?

Actually the pico-platinche with the bno055 is nice because it is smaller
than the diy head tracker  and have more free CPU and memory for the
protocol implementation as the sensor with its built in cpu does drift
elimination and calibration.
As far as I know the bno055 is the only sensor with built in calibration
and drift compensation available to hobbyists.

If the communication is serial over USB, tcp-ip over USB or using WiFi or
Bluetooth does not matter so much at this stage.

Bluetooth might be best for platform flexibility, works with phones, PC and
Mac and workable with Linux. But the same is valid for WiFi., and currently
the Chinese Bluetooth module is larger than the WiFi but needs less power.

And I think I have burnt my BT module with 5v and is waiting for a new
one...

Best Regards
Bo-Erik
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Re: [Sursound] Never do electronic in public.

[umashankar manthravadi]

For the moment, I would like video kept out of motion tracked audio on 
headphones. I want this to be a system where I can sit in a rocking chair and 
listen to music of many kinds on a good pair of headphones and the headtracking 
is only to reinforce the audio image.

Umashankar
p.s. I have ordered bits to build a usb contraption to turn headmovements into 
xy.

Sent from Mail for Windows 10

From: Stefan Schreiber
Sent: Tuesday, February 2, 2016 3:32 AM
To: Surround Sound discussion group
Subject: Re: [Sursound] Never do electronic in public.

David McGriffy wrote:

>
>I got a GearVR recently and it does work better than Google Cardboard. Much
>of this is just comfort, I think, but I understand that it has its own
>gyros, mostly because they are faster. 'Heresay' is that the Oculus Rift
>samples at least 1000Hz. I have actually written an audio rate rotate that
>could handle this, but it does seem like overkill. At normal head turning
>rates, I find interpolating the rotation within each block to be enough.
>
>
>
http://blogs.valvesoftware.com/abrash/latency-the-sine-qua-non-of-ar-and-vr/

(Written by a super-expert of VR)

> Assuming accurate, consistent tracking (and that’s a big if, as I’ll
> explain one of these days), the enemy of virtual registration is
> latency. < If too much time elapses between the time your head starts
> to turn and the time the image is redrawn to account for the new pose,
> the virtual image will drift far enough so that it has clearly wobbled
> (in VR), or so that is obviously no longer aligned with the same
> real-world features (in AR). >

(Elaboration:)

> Suppose you rotate your head at 60 degrees/second. That sounds fast,
> but in fact it’s just a slow turn; you are capable of moving your head
> at hundreds of degrees/second. Also suppose that latency is 50 ms and
> resolution is 1K x 1K over a 100-degree FOV. Then as your head turns,
> the virtual images being displayed are based on 50 ms-old data, which
> means that their positions are off by three degrees, which is wider
> than your thumb held at arm’s length. Put another way, the object
> positions are wrong by 30 pixels. Either way, the error is very
> noticeable.


In other words: There are speed/delay problems, there are sync problems,
there might be more...


> You can do prediction to move the drawing position to the right place,
> and that works pretty well most of the time. Unfortunately, when there
> is a sudden change of direction, the error becomes even bigger than
> with no prediction.


> Tracking latency is highly dependent on the system used. An IMU (3-DOF
> gyro and 3-DOF accelerometer) has very low latency – on the order of 1
> ms – but drifts. < In particular, position derived from the
> accelerometer drifts badly, because it’s derived via double
> integration from acceleration. > Camera-based tracking doesn’t drift,
> but has high latency due to the need to capture the image, transfer it
> to the computer, and process the image to determine the pose; that can
> easily take 10-15 ms. < Right now, one of the lowest-latency
> non-drifting accurate systems out there is a high-end system from NDI,
> which has about 4 ms of latency, so we’ll use that for the tracking
> latency. >



> It would be far easier and more generally applicable to have the
> display run at 120 Hz, which would immediately reduce display latency
> to about 8 ms, bringing total latency down to 12-14 ms.

(s. PlaystationVR...)

> If you ever thought that AR/VR was just a simple matter of showing an
> image on the inside of glasses or goggles, I hope that by this point
> in the blog it’s become clear just how complex and subtle it is to
> present convincing virtual images – and we’ve only scratched the surface.


Wise words... (No, really!)

But not to get stuck and despair: Motion-tracked audio seems to be
so much easier to realize...


Best regards,

Stefan









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Re: [Sursound] Never do electronic in public.

[David Pickett]

At 07:42 02-02-16, umashankar manthravadi wrote:

>For the moment, I would like video kept out of motion tracked audio on
>headphones. I want this to be a system where I can sit in a rocking
>chair and listen to music of many kinds on a good pair of headphones
>and the headtracking is only to reinforce the audio image.

Although I use a pair of Sennheiser HD600 headphones almost every day 
for making and editing recordings, I cant get at all excited about 
having to wear headphones to listen to music for pleasure, and unlike 
mulitchannel loudspeaker surround, I personally regard the effort to 
perfect binaural sound on headphones as a waste of time and 
energy.  This may be my loss; but it is my honest opinion, and others 
are entitled to disagree.


Most young people that I see in the city where I live seem to have 
earbuds permanently in their ears; they are presumably listening to 
normal stereo recordings made for loudspeakers and seem to be quite 
happy with that format and MP3 quality.  I fear it might be rather 
disorienting for such people to be listening to recordings that give 
them cues that contradict those they would get from the environment 
where they are actually standing or walking.  Unlike Umashankar at 
home in his rocking chair, this is at least rather dichotomous, or 
whatever the word is.


David

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Re: [Sursound] Never do electronic in public.

[Stefan Schreiber]

David McGriffy wrote:


Oh how I wish I had time to play with this stuff. At this moment on my
breadboard I have a Teensy 3.2, a 6DOF gyro module, etc. Bluetooth modules
should be in today. 10DOF modules on order. I think the magnetometer is
important for HT to prevent drift. The altitude, perhaps not so much. Of
course, this is for a drone project (I'm writing a book about building
drones). And I have audio projects backed up ...

For audio and head tracking, I have been playing in Unity to Google
Cardboard and now GearVR. I have some demo code for anyone interested in
Unity development.

The standard I hear in the VR world is 20ms "motion to photons". Minimum
frame rate of 60Hz, preferably 90-120Hz. These faster rates do not allow
convolution with the full block size of the listen database, though careful
truncation should be OK.

David McGriffy
VVAudio

 


https://depositonce.tu-berlin.de/bitstream/11303/1318/1/Dokument_28.pdf

(System latency)

Chapter 4.1.3

Figure 4.4 displays the results together with the mean value of all 17 
persons and a
95 %-confidence interval depending on the total latency time. An 
average value of 0.5
was assumed as the threshold that needs to be passed to allow a 
perception. Hence
if the 95 %-confidence interval of the mean value exceeded this limit, 
the respective

total latency time was counted to be perceptible.
Each (total) latency time falling short of 85 ms was ignored by the 
subjects. The
transition between “not perceptible” and “perceptible” occurred in a 
range between
85 ms and 101 ms. For latency times exceeding 101 ms localization 
artifacts were

perceived.



5.2.1

Sandvad and Wenzel [110, 136, 137] have previously investigated the 
influence of
the system’s total latency time on localization. They concluded that 
for producing
real time auralization the auralization system has to meet the 
following requirements:
The total latency time has to be below 91 ms, the update rate has to 
be at least 60 Hz

and a minimal spatial resolution of about 2± is required.



The experiment at IRT which focused on latency (described in section 
4.1.3) produced
similar the results, i. e., a maximal latency time of 81 ms using an 
update rate


of 120 Hz and a spatial resolution of 5± (due to the step-motor). The 
head tracker
system itself had a latency time of theadtracker = 8.3 ms and an 
angular resolution of

0.1±.
Since the electronic auralization system (BRS Processor) itself has a 
shorter latency
time (tBRS < 6 ms), the system’s total latency time is in the order of 
magnitude
of about ttotal = theadtracker + tBRS ' 15 ms. Thus does not exceed 
the upper limit

of 85 ms and fulfils the requirements previously mentioned.



The link to this dissertation originally came from Aaron Heller (I 
was combing some "old" mails... :-) )




The standard I hear in the VR world is 20ms "motion to photons".


I somewhat would like to express my doubts!

You must be aware that update rate and latency are s.th. quite different.

20ms (max.) latency looks (suspiciously) close to 1s/(min. update rate).

I would have thought the same. However, max latency should be < 
significantly greater > than (1/min. update rate) s.


(?)



The standard I hear in the VR world is 20ms "motion to photons".



Sources?! No "hearsay" accepted, at least not at this point!

Best,

Stefan

P.S.: It was all about "Never do MATH in public"... ;-)



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Re: [Sursound] Never do electronic in public.

[Bo-Erik Sandholm]

Apperently there exists a head tracking specialized version of the bno055
called bno070 - but I cannot find a place to buy this.
you can get up to 250 samples / second from that version.

Matthias did not complain about the update rate with the DIY headtracker
http://www.rcgroups.com/forums/showthread.php?t=1677559

http://electronicspurchasingstrategies.com/2014/03/06/hillcrest-bosch-sensortec-collaborate-sensor-hub-solution/

http://docsfiles.com/pdf_bno070.html

http://ae-bst.resource.bosch.com/media/_tech/media/product_flyer/Mobile-Hillcrest-Labs-Sensor-Hub-Product-Brief-BNO0701.pdf

https://www.eiseverywhere.com/file_uploads/5c881a2f6eaaa90ed3f3d30fb20852db_Newsflash_BNO077.pdf


maybe it is better to not think about that and try and use what I have ?

It is easy to find videos about using the bno055 in different projects but
i do not want videos... have not found links to the software used...



Better luck when google github bno055 :-)

https://www.reddit.com/r/virtualreality/comments/3faq11/why_we_need_to_move_to_ambisonic_sound_in_the/

http://vriscoming.com/daydream-vr/

Bo-Erik

2016-02-01 18:56 GMT+01:00 Marc Lavallee <m...@hacklava.net>:

> On Mon, 01 Feb 2016 17:46:47 +
> Stefan Schreiber <st...@mail.telepac.pt> wrote:
> > What is a 10 DOF motion sensor??? (Didn't you mean 9DOF?)
>
> It's 9DOF + barometric pressure, so 9DOF is enough. For more info:
> http://playground.arduino.cc/Main/WhatIsDegreesOfFreedom6DOF9DOF10DOF11DOF
>
> --
> Marc
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Re: [Sursound] Never do electronic in public.

[David McGriffy]

Oh how I wish I had time to play with this stuff. At this moment on my
breadboard I have a Teensy 3.2, a 6DOF gyro module, etc. Bluetooth modules
should be in today. 10DOF modules on order. I think the magnetometer is
important for HT to prevent drift. The altitude, perhaps not so much. Of
course, this is for a drone project (I'm writing a book about building
drones). And I have audio projects backed up ...

For audio and head tracking, I have been playing in Unity to Google
Cardboard and now GearVR. I have some demo code for anyone interested in
Unity development.

The standard I hear in the VR world is 20ms "motion to photons". Minimum
frame rate of 60Hz, preferably 90-120Hz. These faster rates do not allow
convolution with the full block size of the listen database, though careful
truncation should be OK.

David McGriffy
VVAudio

On Mon, Feb 1, 2016 at 5:52 AM, Michael Chapman <s...@mchapman.com> wrote:

> > I just looked back at sursound mails and michael chapman had pointed out
> > that the teensy has four channel audio support. >
> > http://www.pjrc.com/teensy/td_libs_Audio.html
> >
> > umashankar
> >
> >
> Must refuse the credit.
> I just participated in that thread.
>
> Michael
>
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Re: [Sursound] Never do electronic in public.

[Jörn Nettingsmeier]

On 02/01/2016 04:25 PM, David McGriffy wrote:


The standard I hear in the VR world is 20ms "motion to photons". Minimum
frame rate of 60Hz, preferably 90-120Hz. These faster rates do not allow
convolution with the full block size of the listen database, though careful
truncation should be OK.


? the latency of a convolver has nothing to do with the length of the 
kernel, only with its own blocksize. with a standard pc, it should be 
easily possible to get under 3 ms latency, even less if you're prepared 
to upsample your hrtfs and content to 96k (and burn twice as much cpu, 
and waste storage). in any case, you can make use of the full length of 
the hrtfs.


--
Jörn Nettingsmeier
Lortzingstr. 11, 45128 Essen, Tel. +49 177 7937487

Meister für Veranstaltungstechnik (Bühne/Studio)
Tonmeister VDT

http://stackingdwarves.net

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Re: [Sursound] Never do electronic in public.

[Marc Lavallee]

On Mon, 01 Feb 2016 17:46:47 +
Stefan Schreiber  wrote:
> What is a 10 DOF motion sensor??? (Didn't you mean 9DOF?)

It's 9DOF + barometric pressure, so 9DOF is enough. For more info:
http://playground.arduino.cc/Main/WhatIsDegreesOfFreedom6DOF9DOF10DOF11DOF

--
Marc
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