> > At least you would have to shift the speaker positions and find or > find/interpolate the HRIR positions, right? (We are speaking of a > head-tracked decoder.)
No, instead we rotate the soundfield *before* decoding. > FOA seems to have some problems with height. One reason could be that > height localizations seems to happen at quite high frequencies. Just some > hint which would have to be treated in depth... > > However, my interpretation of your words is that JauntVR maybe doesn't > employ a 3D audio decoder. This is claimed in the articles about the > company. Are they doing 3D audio decoding or not, then? > > (The question is even more justified if I hint to the fact that you need > more than 4 speakers if realizing any 3D decoder for FOA... So?!) We are doing 3D audio decoding with respect to listener motion, i.e., we do tilt & tumble rotation in addition to horizontal. So even with a horiz-only downmix the decoded content is informed by listener orientation in 3D. We have tried David's binaural + height decoder and agree that it's not convincing enough in its current form. We are exploring HOA upmixing and other spatial formats, but can't provide any details yet. Of course, we have constructed a spherical listening room which does full XYZ decoding, but our primary interest is in binaural. Finally, thanks for the technical response. Because this is a technical > forum, and we can't work with PR information - which might be misleading, > as we have seen. (Speaking about the 3D audio part. I would be happy to > hear the answer if the JauntVR people are doing horiz.-only or 3D decoding. > Without this information we don't know what we are talking about!) Now you know :) Cheers, Adam > > > > NFC I think will depend on the situation. If you are using room >> responses, then NFC at the distance of the speakers in that room might >> help, otherwise, I don’t know what distance to use. We could choose a >> default as is sometimes done, but I think that would still be correcting >> for something that isn’t happening in a binaural system. If others have >> experience or especially analytical answers to any of these questions, I’d >> be very interested as it’s something I’m actively working on. >> >> >> David >> VVAudio >> >> >> >> >>> It should be stated that our current implementation is very much a >>>> prototype and will require a good deal of refinement and >>>> personalization. >>>> >>>> >>>> >>> It might be oth worthwile and feasible for you to investigate the use of >>> individual HRIRs/HRTFs. (Measured OR derived form 3D scans/photographs, as >>> I have suggested. The latter method is definitively more complicated, but >>> way faster.) >>> >>> >> >> >> >> >> >>> Best regards, >>> >>> Stefan >>> >>> >>> >>> >>> >>>> >>>> >>>>> Len Moskowitz wrote: >>>>> >>>>> Jaunt VR has developed a virtual reality camera. They're using TetraMic >>>>> >>>>> >>>>>> for recording audio, decoding with headtracking for playback over >>>>>> headphones and speakers. For video playback they're using the Oculus >>>>>> Rift. >>>>>> >>>>>> http://time.com/49228/jaunt-wants-to-help-hollywood-make- >>>>>> virtual-reality-movies/ >>>>>> http://gizmodo.com/meet-the-crazy-camera-that-could-make- >>>>>> movies-for-the-oc-1557318674 >>>>>> >>>>>> >>>>>> >>>>> Citing from this link: >>>>> >>>>> A close-up of the 3D microphone that allows for 3D spacialized audio. >>>>> If >>>>> >>>>> >>>>>> you're wearing headphones, there's actually headtracking for the >>>>>> Oculus to >>>>>> tell which direction you're looking--when you change your view, the >>>>>> sound >>>>>> mix will also change to match, in order to keep the sound in the same >>>>>> space. >>>>>> >>>>>> >>>>>> >>>>> I have suggested this possibility before, for example here: >>>>> >>>>> http://comments.gmane.org/gmane.comp.audio.sursound/5172 >>>>> >>>>> (obviously thinking of some < audio-only > application, without any >>>>> video. It was already clear that the Oculus Rift included all necessary >>>>> hardware for HT audio decoding, although Oculus didn't do this in 2012 >>>>> or >>>>> 2013.) >>>>> >>>>> This suggestion led (by influence or coincidence) to some further >>>>> developments, which could be followed on the sursound list: >>>>> >>>>> http://comments.gmane.org/gmane.comp.audio.sursound/5387 >>>>> >>>>> To be frank: At least two "groups" of people on this list have >>>>> demonstrated head-tracked decoding of FOA recently and < before > >>>>> Jaunt VR, >>>>> done in a very similar fashion. I could name Hector Centeno and >>>>> Bo-Erik >>>>> Sandholm (Bo-Erik introduced the external HT hardware, whereas the >>>>> Android >>>>> app by Hector already existed), further Matthias Kronlachner at IEM >>>>> Graz. >>>>> If not more people... >>>>> >>>>> Far from complaining about this, I would welcome this coincidence or >>>>> "coincidence". (The "VR movie" people and "our" list colleagues use >>>>> basically the same HT decoder technology, and maybe even decoding >>>>> software.) Because this all shows that Ambisonics is mature enough to >>>>> be >>>>> used even for some very sophisticated applications, if we speak about >>>>> cinematic VR demonstrations... (We are all using "the power of HT >>>>> decoded >>>>> FOA, in VR worlds, VR movies, and maybe even for 3D audio music >>>>> recordings"... ;-) ) >>>>> >>>>> Seeing the recent and ongoing development activities in areas like UHD, >>>>> Mpeg-H 3D audio aka ISO/IEC 23008-3, gaming, VR, 3D movies and now "VR >>>>> movies" (this is not a technical term yet), it is probably a good >>>>> question >>>>> why surround sound/3D audio is used in so many areas, but < still not >>>>> > for >>>>> (published) music recodings. (This situation looks increasingly < >>>>> unbelievable >. ) >>>>> >>>>> >>>>> Anyway: Congratulations to Len and TetraMic, who are involved in these >>>>> activities! >>>>> >>>>> >>>>> Now, I have some suggestions for further improvement, to our colleagues >>>>> and also Jaunt VR/TetraMic: >>>>> >>>>> If the reference quality for HT binaural systems is about this >>>>> >>>>> http://smyth-research.com/technology.html, >>>>> >>>>> you would still have to employ personalized HRTFs (HRIR/BRIR) data sets >>>>> into your decoder. (HRIR is anechoic. BRIR includes room acoustics.) >>>>> >>>>> It is probably possible to calculate both HRIR and BRIR data sets from >>>>> 3D >>>>> scans, or even from "plain" photographs. (This has been done at least >>>>> in >>>>> the case of HRIR/HRTF data sets, derived from optical 3D scans or >>>>> photographs of the torso/head/ear shapes. Probably there is still ample >>>>> space to improve the existing methods to calculate HRIRs/HRTFs from >>>>> optical >>>>> data. For example, you could compare your calculation algorithm and >>>>> corresponding real-world acoustical measurements, and follow some >>>>> evolutionary improvement strategy. Matching calculation results and >>>>> actual >>>>> measurements closer and closer, after each algorithm generation. Just a >>>>> quick idea...) >>>>> >>>>> To calculate some (reverbant) BRIR data set (transfer function of some >>>>> listener in a room), you could maybe apply some form of acoustical >>>>> raytracing. >>>>> >>>>> It would be far easier to < calculate > personalized HRIR/BRIR data >>>>> sets >>>>> than to measure them. (Because acoustical full-sphere measurements >>>>> would >>>>> require to measure hundreds or thousands of different positions, over a >>>>> full or at least half 3D sphere.) >>>>> >>>>> >>>>> Beside the suggestion to investigate the use of individual >>>>> HRIRs/HRTFs, I >>>>> have a direct question to Jaunt VR: >>>>> >>>>> What specific set of HRIRs/HRTFs (or BRIRs?) are you currently using as >>>>> part of your Ambisonics --> head-tracked binaural decoder? >>>>> >>>>> (I would imagine that you will have tested some existing collections, >>>>> and >>>>> chosen some specific set according to your listening results. Because >>>>> you >>>>> are using data sets and probably also software of other >>>>> people/parties, I >>>>> believe it would be fair enough to answer this question. ) >>>>> >>>>> >>>>> Best regards, >>>>> >>>>> Stefan >>>>> >>>>> P.S.: If this is possible, I also would be curious to hear what HT >>>>> update >>>>> frequency you are using for the audio decoder, and maybe to ask some >>>>> other >>>>> questions. >>>>> >>>>> >>>>> >>>>> >>>>> >>>>> >>>>> http://www.engadget.com/2014/04/03/jaunt-vr/ >>>>> >>>>> >>>>>> Len Moskowitz (mosko...@core-sound.com) >>>>>> Core Sound LLC >>>>>> www.core-sound.com >>>>>> Home of TetraMic >>>>>> >>>>>> _______________________________________________ >>>>>> Sursound mailing list >>>>>> Sursound@music.vt.edu >>>>>> https://mail.music.vt.edu/mailman/listinfo/sursound >>>>>> >>>>>> >>>>>> >>>>>> >>>>> _______________________________________________ >>> Sursound mailing list >>> Sursound@music.vt.edu >>> https://mail.music.vt.edu/mailman/listinfo/sursound >>> >>> >> >> _______________________________________________ >> Sursound mailing list >> Sursound@music.vt.edu >> https://mail.music.vt.edu/mailman/listinfo/sursound >> >> >> > > _______________________________________________ > Sursound mailing list > Sursound@music.vt.edu > https://mail.music.vt.edu/mailman/listinfo/sursound > -------------- next part -------------- An HTML attachment was scrubbed... URL: <https://mail.music.vt.edu/mailman/private/sursound/attachments/20140516/58ddc1b8/attachment.html> _______________________________________________ Sursound mailing list Sursound@music.vt.edu https://mail.music.vt.edu/mailman/listinfo/sursound
