Hi all Listening here: Except that all of us have different HRTFs. This means that while you can convert UHJ to B-format and then to Binaural, the opposite is not true.
Secondly, with today's app enabled mobile phones a B-format player could be released by anyone. Pop in a custom HRTF file and then you have full periphonic sound on your mobile. Also being able to calibrate out the phones..... Thirdly, there is no reason why ear-buds could not be good for this audio especially in-ears. The big problem here is that there is a lot of DSP that would have to be done on the fly. Given however how much is allready done to decode the likes of AAC audio, it should not be intractable. A B-format that can be used on mobile devices seems to be an interesting idea. The problem seems to be infrastructure. Being able to tag an audio stream as HOA and then automatically decode it seems to be the big problem. I agree with the statement above that a big step would be to get a decoder into VLC via ffmpeg. this would indeed seem to be a big first step. There are published HOA decoder coefficients for 5.1 and it is relatively easy to compute a Cube format array stream and then apply a HRTF to it. The work just has to be done. Perhaps all that is really needed in terms of a format is a way to tag an audio stream in Matroska, .ogg, .mp4 and avi as an ambisonic stream instead of a normal multi-channel one, along with a fixed channel order. Once in ffmpeg lots of other things come for free i.e. firefox, chrome, VLC, mplayer, mplayer-classic, windows media player for those with the ffmplayer codec installed. Someone just has to step up and do it. The best option is not to define a compression technique, but to define a audio layout and specify a channel order. If you pack 2 streams into the file say with the UHJ stereo and stream 2 as the other two streams with a different magic string as their designator, then you have a backwards compatible playback format that can be decoded into WXYZ ambisonic with little loss and recover the audio. The same is true if you were to just render the audio as 2L = sqrt(2)W + Y and 2R = sqrt(2)W - Y easy to get W and Y out, then just ship X and Z in another stream with a custom tag. Alexis Shaw On 30 October 2012 21:24, Peter Lennox <p.len...@derby.ac.uk> wrote: > Am I missing something? - for mobile use, wouldn't B-format to binaural be > better than UHJ? > Dr Peter Lennox > > School of Technology, > Faculty of Arts, Design and Technology > University of Derby, UK > e: p.len...@derby.ac.uk > t: 01332 593155 > ________________________________________ > From: sursound-boun...@music.vt.edu [sursound-boun...@music.vt.edu] On > Behalf Of Richard Lee [rica...@justnet.com.au] > Sent: 30 October 2012 19:51 > To: 'Surround Sound discussion group' > Subject: Re: [Sursound] Patent application: Data structure for HOA > > > Unless things have changed a lot, last I checked lossy compression > messes up phase relationships, and that would be an issue for things like > UHJ, which as long as portable stereo players with limited battery life > (and thus limited CPUs), is the only viable, because stereo compatible, > distribution format. > > > At this point in time, not only is most music listened on mobile > devices, most music is even purchased on mobile devices, and that's > strictly a stereo (or maybe binaural) world. > > Try this simple experiment. Take your favourite Nimbus UHJ CD and rip it > using the most evil MP3 encoder you can find .. probably the one built into > the latest Windoz Media Player. > > Do this at 256kB/s and also (shock! horror!) at 128kB/s. Now listen to > the resultant files on a mobile device. Then you can pontificate to us on > how the musicality has all escaped and no one is going to find these > acceptable. > > You can also rip to a WAV file if your mobile device will play these and > compare the MP3s with the 'original'. > > This is just testing Ronald's assertion about compressed UHJ on stereo > mobile devices. I dunno about full UHJ surround decode cos there don't > seem to be any good ones in the public domain. > > PS I expect you to hear ve.eery slight differenes with one MP3 and > probably none with the other. I won't insist on Double Blind bla bla but > you might find that educational. > _______________________________________________ > Sursound mailing list > Sursound@music.vt.edu > https://mail.music.vt.edu/mailman/listinfo/sursound > > _____________________________________________________________________ > The University of Derby has a published policy regarding email and > reserves the right to monitor email traffic. If you believe this email was > sent to you in error, please notify the sender and delete this email. > Please direct any concerns to info...@derby.ac.uk. > _______________________________________________ > Sursound mailing list > Sursound@music.vt.edu > https://mail.music.vt.edu/mailman/listinfo/sursound > -------------- next part -------------- An HTML attachment was scrubbed... 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