Re: [Sursound] Reduced set of B-format (or HOA) to binaural filters
On 26 May 2016, at 01:04, Eric Benjamin <eb...@pacbell.net<mailto:eb...@pacbell.net>> wrote: I have used that symmetry in the past. I assume that everyone does. Hi Eric, good to know that it’s used by everybody and I wasn’t totally off in my “revelations” :-). It wasn’t mentioned before in the discussion about generating HOA to binaural filters (even though nothing about symmetry was mentioned either). So is this how it is usually done? Convolving all (N+1)^2 HOA channels of order N with the set of binaural filters and summing for the left ear, and then doing the same for the right but with inverted polarity for the (N^2+N)/2 HOA channels of m<0 ? Best regards, Archontis -- next part -- An HTML attachment was scrubbed... URL: <https://mail.music.vt.edu/mailman/private/sursound/attachments/20160525/4e289e4b/attachment.html> ___ 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.
Re: [Sursound] Reduced set of B-format (or HOA) to binaural filters
I have used that symmetry in the past. I assume that everyone does. Sent from Yahoo Mail on Android On Wed, May 25, 2016 at 8:37 AM, Politis Archontis<archontis.poli...@aalto.fi> wrote: Hi, There has been some discussion before on B-format or HOA to binaural filters (HRTF-based), which no matter if it goes through a virtual decoder or with a direct HRTF-to-Bformat approach, two times the number of HOA channels of filters are needed (so 8 for B-format, 18 for 2nd-order HOA, 32 for 3rd-order HOA etc. ). Playing around a bit I realized that if the HRTFs are made left-right symmetric, which makes sense to always force for non-individialized ones (and also for individualized sometimes), then a smaller set of filters is needed due to this left-right symmetry. For example for B-format binaural filters, the W, X and Z channel would have exactly the same filters, while the Y channel would have the same filter with a polarity inversion for one ear with respect to the other. Hence 4 filters instead of 8. Thinking about it, it simply makes sense, as the spherical harmonics are themselves either symmetric or antisymmetric with respect to the x-z (median) plane. This is also what makes mirroring of a HOA sound scene from left to right for example, as easy as inverting certain HOA channels. My question to any of the decoder developers on the list is if you have seen that anywhere analyzed or mentioned in the context of binaural decoding?? Many thanks, Archontis Politis -- next part -- An HTML attachment was scrubbed... URL: <https://mail.music.vt.edu/mailman/private/sursound/attachments/20160525/a7b7b617/attachment.html> ___ 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. -- next part -- An HTML attachment was scrubbed... URL: <https://mail.music.vt.edu/mailman/private/sursound/attachments/20160525/a60abf95/attachment.html> ___ 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.
Re: [Sursound] Reduced set of B-format (or HOA) to binaural filters
Hi Fons, thanks for the info, it is clear to me now that for any order of HOA to binaural decoding, only (N+1)^2 filters are required for left-right symmetric HRTFs, with a subsequent polarity inversion of N channels corresponding to the left-right antisymmetric SHs (the sine ones) in order to get one of the two ear signals. Best, Archontis On 25 May 2016, at 21:07, Fons Adriaensen <f...@linuxaudio.org<mailto:f...@linuxaudio.org>> wrote: On Wed, May 25, 2016 at 03:37:34PM +, Politis Archontis wrote: My question to any of the decoder developers on the list is if you have seen that anywhere analyzed or mentioned in the context of binaural decoding?? Haven't seen it in any publications, but the 2nd and 3rd order amb2bin apps I wrote recently work as you suggest. The convolutions do AMB -> M/S, then M/S -> L/R is trivial. Ciao, -- FA A world of exhaustive, reliable metadata would be an utopia. It's also a pipe-dream, founded on self-delusion, nerd hubris and hysterically inflated market opportunities. (Cory Doctorow) ___ Sursound mailing list Sursound@music.vt.edu<mailto:Sursound@music.vt.edu> https://mail.music.vt.edu/mailman/listinfo/sursound - unsubscribe here, edit account or options, view archives and so on. -- next part -- An HTML attachment was scrubbed... URL: <https://mail.music.vt.edu/mailman/private/sursound/attachments/20160525/00f4fe1e/attachment.html> ___ 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.
Re: [Sursound] Reduced set of B-format (or HOA) to binaural filters
On Wed, May 25, 2016 at 03:37:34PM +, Politis Archontis wrote: > My question to any of the decoder developers on the list is if you > have seen that anywhere analyzed or mentioned in the context of > binaural decoding?? Haven't seen it in any publications, but the 2nd and 3rd order amb2bin apps I wrote recently work as you suggest. The convolutions do AMB -> M/S, then M/S -> L/R is trivial. Ciao, -- FA A world of exhaustive, reliable metadata would be an utopia. It's also a pipe-dream, founded on self-delusion, nerd hubris and hysterically inflated market opportunities. (Cory Doctorow) ___ 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.
Re: [Sursound] Reduced set of B-format (or HOA) to binaural filters
Or http://www.brucewiggins.co.uk/?page_id=3 On Wed, 25 May 2016 17:57 Marc Lavallee, <m...@hacklava.net> wrote: > > You can get it here: > http://www.ambisonia.com/Members/DrWig/bwphdthesis.pdf/ > > > On Wed, 25 May 2016 16:50:38 + > Politis Archontis <archontis.poli...@aalto.fi> wrote: > > > Thanks a lot Bruce for the pointers, > > I will check your work! > > > > Regards, > > Archontis > > > > On 25 May 2016, at 19:42, Bruce Wiggins > > <bruce.wigg...@gmail.com<mailto:bruce.wigg...@gmail.com>> wrote: > > > > Definately mentioned and looked at in > > Wiggins, B. Paterson-Stephens, I., Schillebeeckx, P. (2001) The > > analysis of multi-channel sound reproduction algorithms using HRTF > > data. 19th International AES Surround Sound Convention, Germany, p. > > 111-123. > > > > Wiggins, B. (2004) An Investigation into the Real-time Manipulation > > and Control of Three-dimensional Sound Fields. PhD thesis, University > > of Derby, Derby, UK. p. 103 > > > > See http://www.brucewiggins.co.uk/ for my look at the you tube > > implementation which also assumes symmetry.. > > > > Cheers > > > > Bruce > > > > On Wed, 25 May 2016 16:38 Politis Archontis, > > <archontis.poli...@aalto.fi<mailto:archontis.poli...@aalto.fi>> wrote: > > > > Hi, > > > > There has been some discussion before on B-format or HOA to binaural > > filters (HRTF-based), which no matter if it goes through a virtual > > decoder or with a direct HRTF-to-Bformat approach, two times the > > number of HOA channels of filters are needed (so 8 for B-format, 18 > > for 2nd-order HOA, 32 for 3rd-order HOA etc. ). > > > > Playing around a bit I realized that if the HRTFs are made left-right > > symmetric, which makes sense to always force for non-individialized > > ones (and also for individualized sometimes), then a smaller set of > > filters is needed due to this left-right symmetry. For example for > > B-format binaural filters, the W, X and Z channel would have exactly > > the same filters, while the Y channel would have the same filter with > > a polarity inversion for one ear with respect to the other. Hence 4 > > filters instead of 8. > > > > Thinking about it, it simply makes sense, as the spherical harmonics > > are themselves either symmetric or antisymmetric with respect to the > > x-z (median) plane. This is also what makes mirroring of a HOA sound > > scene from left to right for example, as easy as inverting certain > > HOA channels. > > > > My question to any of the decoder developers on the list is if you > > have seen that anywhere analyzed or mentioned in the context of > > binaural decoding?? > > > > Many thanks, > > Archontis Politis > > > > > > > > > > > > -- next part -- > > An HTML attachment was scrubbed... > > URL: < > > > https://mail.music.vt.edu/mailman/private/sursound/attachments/20160525/a7b7b617/attachment.html > > > > ___ > > 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. > > > > -- next part -- > > An HTML attachment was scrubbed... > > URL: > > < > https://mail.music.vt.edu/mailman/private/sursound/attachments/20160525/f793cacf/attachment.html > > > > ___ Sursound mailing list > > Sursound@music.vt.edu<mailto:Sursound@music.vt.edu> > > https://mail.music.vt.edu/mailman/listinfo/sursound - unsubscribe > > here, edit account or options, view archives and so on. > > > > -- next part -- > > An HTML attachment was scrubbed... > > URL: > > < > https://mail.music.vt.edu/mailman/private/sursound/attachments/20160525/e9cb0744/attachment.html > > > > ___ 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. > > ___ > 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. > -- next part -- An HTML attachment was scrubbed... URL: <https://mail.music.vt.edu/mailman/private/sursound/attachments/20160525/5bee413d/attachment.html> ___ 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.
Re: [Sursound] Reduced set of B-format (or HOA) to binaural filters
Definately mentioned and looked at in Wiggins, B. Paterson-Stephens, I., Schillebeeckx, P. (2001) The analysis of multi-channel sound reproduction algorithms using HRTF data. 19th International AES Surround Sound Convention, Germany, p. 111-123. Wiggins, B. (2004) An Investigation into the Real-time Manipulation and Control of Three-dimensional Sound Fields. PhD thesis, University of Derby, Derby, UK. p. 103 See http://www.brucewiggins.co.uk/ for my look at the you tube implementation which also assumes symmetry.. Cheers Bruce On Wed, 25 May 2016 16:38 Politis Archontis, <archontis.poli...@aalto.fi> wrote: > Hi, > > There has been some discussion before on B-format or HOA to binaural > filters (HRTF-based), which no matter if it goes through a virtual decoder > or with a direct HRTF-to-Bformat approach, two times the number of HOA > channels of filters are needed (so 8 for B-format, 18 for 2nd-order HOA, 32 > for 3rd-order HOA etc. ). > > Playing around a bit I realized that if the HRTFs are made left-right > symmetric, which makes sense to always force for non-individialized ones > (and also for individualized sometimes), then a smaller set of filters is > needed due to this left-right symmetry. For example for B-format binaural > filters, the W, X and Z channel would have exactly the same filters, while > the Y channel would have the same filter with a polarity inversion for one > ear with respect to the other. Hence 4 filters instead of 8. > > Thinking about it, it simply makes sense, as the spherical harmonics are > themselves either symmetric or antisymmetric with respect to the x-z > (median) plane. This is also what makes mirroring of a HOA sound scene from > left to right for example, as easy as inverting certain HOA channels. > > My question to any of the decoder developers on the list is if you have > seen that anywhere analyzed or mentioned in the context of binaural > decoding?? > > Many thanks, > Archontis Politis > > > > > > -- next part -- > An HTML attachment was scrubbed... > URL: < > https://mail.music.vt.edu/mailman/private/sursound/attachments/20160525/a7b7b617/attachment.html > > > ___ > 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. > -- next part -- An HTML attachment was scrubbed... URL: <https://mail.music.vt.edu/mailman/private/sursound/attachments/20160525/f793cacf/attachment.html> ___ 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.
[Sursound] Google Jump Spatial Audio
Google Jump/YouTube info page on Spatial Audio https://support.google.com/jump/answer/6399746 ___ 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.
[Sursound] Reduced set of B-format (or HOA) to binaural filters
Hi, There has been some discussion before on B-format or HOA to binaural filters (HRTF-based), which no matter if it goes through a virtual decoder or with a direct HRTF-to-Bformat approach, two times the number of HOA channels of filters are needed (so 8 for B-format, 18 for 2nd-order HOA, 32 for 3rd-order HOA etc. ). Playing around a bit I realized that if the HRTFs are made left-right symmetric, which makes sense to always force for non-individialized ones (and also for individualized sometimes), then a smaller set of filters is needed due to this left-right symmetry. For example for B-format binaural filters, the W, X and Z channel would have exactly the same filters, while the Y channel would have the same filter with a polarity inversion for one ear with respect to the other. Hence 4 filters instead of 8. Thinking about it, it simply makes sense, as the spherical harmonics are themselves either symmetric or antisymmetric with respect to the x-z (median) plane. This is also what makes mirroring of a HOA sound scene from left to right for example, as easy as inverting certain HOA channels. My question to any of the decoder developers on the list is if you have seen that anywhere analyzed or mentioned in the context of binaural decoding?? Many thanks, Archontis Politis -- next part -- An HTML attachment was scrubbed... URL: <https://mail.music.vt.edu/mailman/private/sursound/attachments/20160525/a7b7b617/attachment.html> ___ 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.
