On 4 Apr 2012, at 01:13, Sampo Syreeni <de...@iki.fi> wrote: > Eric, could you tell us a little bit about the patent status of the CAF > implementation within libsndfile? And while we're at it, what would be tha > chance of getting some newer, purely open source format into the library, if > coded by an outside agency? Just in case?
CAF is purely open source, it's 64-bit, it's extensible, it's taggable, and it has provisions such that if your CAF-writing program (e.g. DAW) crashes, you still have a valid/recoverable file until the point in time when the program crashes (which is not the case with most other file formats). So why create more file formats, we have already too many. If not CAF, then use an MP4 container format, just not yet another format, we've got plenty crappy ones already. Rather use something that has already existing infrastructure. >> If it is pitched on the basis that most of the speakers will just present >> subtle degree of ambience, which many listeners might not notice at all, any >> more than they do in the concert hall or rock venue, I suspect its >> commercial appeal will be negligible. > > Have you ever heard what pantophonic ambisonic, decoded from two channels to > four speakers, can do? Eero Aro was once kind enough to show me that, and it > was downright eerie. Even as the very, very limited BHJ version. The setup > was nowhere near perfect, the playback came from analog tape, and so on... > Yet stuff seemed to come from the sides and behind me. It stayed there as > well, when I turned my head. Exactly my point, that's why I'm pissed when the n-th order snobism kills everything from UHJ to G-Format to planar-only B-format. I wished anything beyond that would, for at leas the next decade be clearly marked "academic research only", and stay out of the way when it comes to practical applications (except when used as an internal intermediate format within processing modules). There's a good chance that within the next year or two, Amazon and Apple will start selling lossless encoded audio. In Stereo. That means UHJ will be an option. So there. UHJ is all we need, it's good enough for a start. Once people know UHJ, then you can tell them that using a third channel to get to horizontal-only B-format it gets even better. Once that's established in the mainstream you can start talking about Z-axis and higher orders. Not before. Step-by-step. All commercially relevant music is sold essentially stereo only. That means the only thing that's relevant for the near and mid-term is UJH, with binaural and 5.1 (4.0) decoding. Plus maybe 5.1 G-Format for music videos on DVD or surround capable video downloads. Period. > Of course it wouldn't have. The difference is that now every piece of real > audio hardware has a signal processor inside it. Now, every piece of hardware > *and* software can easily, effortlessly and cheaply adapt to the ambisonic > viewpoint. First order, it's no more than 20-30 lines of code. > > So why *not* do it, since it's really, really good even on the minimum four > speakers? > > We can do both of those better than the folks who do them now, discretely. I > can promise you that even at first order. No kidding either. :) > > Why don't the commercial manufacturers do what the early ambisonic decoder > makers did, and limit the choices to just two: aspect ratio of the > (rectangular) rig, and its mean diameter? I mean, it works spectacularly well > regardless of the number of speakers, it's intuitive, and it can be easily > generalized to non-ambisonic modes of playback as well. > > This ain't rocket surgery, you know. That's the realistic attitude I'm missing for the most part around here.... >> So there is absolutely no danger at all of Apple "locking in" B-Format as it >> is all but un-lockable. > > Not much, but there is some: if theirs is the only widely spread format which > carries B-format, and its ancillary online features are held behind a patent > wall, then de facto B-format's only viable distribution channel could be > owned by Apple. That'd be a real shame. Not really. Compare to what we have now. Imagine a hypothetical Apple patent wall that gets Ambisonic B-Format limited to the iTunes music store. That's hundreds of millions of users! And what do we have now? A few thousands of enthusiasts and academics. I eat the patent pill to get the tech spread and the content creators on board. The patents expire in less time than has already been wasted and resulted in Ambisonics going nowhere. > Thus, where is our open sourced hardware for ambisonic? We used to have > something like that in the analogue age. Where is the counterpart of that for > the DSP age? :) The problem is: who still needs hardware? Unless it's incorporated into something like an Oppo DVD/BD player, which hooks up directly to a power amp, the hardware of choice is something like an AppleTV that gets its data stream from a computer server, i.e. iTunes. At least that's the scenario for the average techno-phile user without a huge budget. The luddites still have CD players, but they are going to die out just like the Vinyl and 8-Track are slowly sliding towards their graves. > Want a minimal and purposely highly (even overtly) extensible one? That I can > design. In fact I've meant to do something like this from teenage up. :) Sounds like CAF to me ;) Ronald _______________________________________________ Sursound mailing list Sursound@music.vt.edu https://mail.music.vt.edu/mailman/listinfo/sursound
