search for: ambisonics

....RFC.6716.xml'> <!ENTITY rfc7845 PUBLIC '' 'http://xml.resource.org/public/rfc/bibxml/reference.RFC.7845.xml'> ]> <?rfc toc="yes" symrefs="yes" ?> <rfc ipr="trust200902" category="std" docName="draft-graczyk-opus-ambisonics" updates="7845"> <front> <title abbrev="Opus Ambisonics">Ambisonics in an Ogg Opus Container</title> <author initials="M.G." surname="Graczyk" fullname="Michael Graczyk"> <organization>Google Inc.</organiza...

...is a general > container and isn't just for Opus. Rephrased to "... of audio. It can be used to encapsulate streamscoded using the Opus codec." > Section 3: "A demuxer implmentation encountering Channel Mapping Family > 254 SHOULD interpret the Opus stream as containing ambisonics with the > format described in Section 3.1." > > Aside from changing 254 to 2, the "SHOULD" should be a "MUST". Changed to "MUST". I used SHOULD because that is what is in RFC7845 5.1.1.4. I reasoned that if an implementation were allowed to treat mapping...

Hi Andrew, I suspect that the configure option should be enable-ambisonics (instead of enable_ambisonics), but for each of opus, libopusenc, opusfile and opus-tools git repos (on master branch), when I try "./configure --enable-ambisonics", I get this error message: configure: WARNING: unrecognized options: --enable-ambisonics Thanks for your help. Marc Le 1...

Unfortunately, ambisonics aren't exposed in opusenc yet, thus the trouble. They're an API-only feature, but it's a good time to discuss what such a command-line interface would look like, notably: how to specify multiple streams & stream order, select the mapping family, coupled channels, and how to specify...

...de a "producer's suggestion for best stereo decode". This would be in the form of angle/azimuth for the 3 axis ... and would act as a 'hint' for ambisonic aware players to offer a stereo decode recommended by the producer. (this kind of thing is really leveraging the power of ambisonics). We originally thought that this could be done in the comment headers, but it has been suggested that this would not be an appropriate place to put this. regards, Etienne

Tim, Would you mind giving me a more specific example of the sort of document that you think this should look like? I'd like to write up something that is somewhat final. On Mon, May 2, 2016 at 9:30 PM, Michael Graczyk <mgraczyk at google.com> wrote: > On Fri, Apr 29, 2016 at 4:32 PM, Timothy B. Terriberry > <tterribe at xiph.org> wrote: > > As a general point,

Hi Opus list. I subscribed because your discussion on the IETF draft ("Ambisonics in an Ogg Opus Container") was mentioned on the sursound list. I tried Opus for ambisonics more than a year ago. It does works with uncoupled channels (I had to patch the encoder). I don't know what else could be done to optimize support for ambisonics, as I'm not a codec expert. So...

...39;t sure where to post > it, but seeing as the tags are called "vorbis comments" I thought vorbis, > rather than ogg-dev, would be the right choice. (actually, I'm not even a > developer anyway) Hi Gabriel, I doubt whether the Xiph community would promote a file format for Ambisonics without first seeing whether it had the support of the Ambisonic community *and* seeing it used in the wild. The Ambisonic crowd all hang out on the sursound list,(1) so you should post your proposal over there. (Links have been collected together at the end.) However, there was a heated discuss...

On Mon, Apr 25, 2016 at 9:32 AM, Timothy B. Terriberry <tterribe at xiph.org> wrote: > Jean-Marc Valin wrote: >> >> Would it make sense to allow an arbitrary number of channels and just >> "truncate" the list of channels. For example, two-channel ambisonics >> would be W plus X and three-channel would be W, X and Y. The idea is >> that you would get these mappings for free -- if there's any use for >> them anyway. > > > Well, more specifically, the channel count is stored in the main header, not > in the channel mappi...

On Sat, 28 May 2016 16:21:33 -0700, Michael Graczyk <mgraczyk at google.com> wrote : > Hi Marc, Hi Micheal. > On Sat, May 28, 2016 at 10:44 AM, Marc Lavallée <marc at hacklava.net> > wrote: > > I subscribed because your discussion on the IETF draft ("Ambisonics > > in an Ogg Opus Container") was mentioned on the sursound list. > > Thanks for your interest! Please feel free to voice your support for > this work on the codec at ietf.org mailing list. The more support the > better. I will! > > I tried Opus for ambisonics more...

...on tools and software modules (ffmpeg/libav in particular). Based on my reading of the libopus code and the IETF spec, it seems one reasonable option would be to add a new "Channel Mapping Family" for ambisonic audio [2]. The mapping family would indicate to the decoder that the audio is ambisonics and the channel mapping array would indicate which ambisonic channel (W, X, Y, etc) corresponds to which coded stream. This representation is analogous to Opus headers for surround sound. There are a few caveats though. Although we believe we can achieve good compression at first without changing...

Friendly ping for the opus-tools patch... ---------- Forwarded message --------- From: Drew Allen <bitllama at google.com> Date: Mon, Mar 19, 2018 at 2:53 PM Subject: Re: [PATCH] Support for Ambisonics To: opus at xiph.org <opus at xiph.org> On Mon, Mar 19, 2018 at 11:52 AM Drew Allen <bitllama at google.com> wrote: > Hello all, > > Sorry for the delay (got really sick last week). > > Attached are updated patches for libopus, libopusenc, opusfile and > opus-tools...

All, Progress has been made on the proposed draft spec for integrating ambisonics into vorbis. We are not yet finished (should be soon), but you can see the progress here: http://docs.google.com/Doc?id=df4dtw69_3626qqq6st The issue we have hit now concerns how/who would implement the encoding and decoding in Vorbis Tools. Because ambisonics uses spherical harmonic components,...

>Yesterday I have finished writing the ambisonic pan filter for oggenc. May I ask what this "pan filter" is? I made some tentative suggestions for coupling Ambisonic B-format in a post "Vorbis Ambisonic coupling" on 4feb07 I gather from the last monthly meeting, that some of you, including Monty, had problems with the phase behaviour of B-format. Would anyone like a

Hi, I have posted this three times to the flac-dev, vorbis-dev, and ogg-dev mailing lists. I wanted to see what code there was currently to support Ambisonics. So I downloaded the code from the xiph download page for libogg-1.1.3, libvorbis-1.1.2, vorbis-tools-1.1.1 and flac-1.1.4, but wasn't able to find anything. If it exists then I missed it, so could somebody please point me to it. Many thanks, Martin -- Martin J Leese E-mail: martin.leese@s...

>I have been giving some thought to how to include Ambisonics in Ogg Vorbis. As I understand it, mapping type = 1 was meant from the start to indicate an Ambisonic stream. The only other information required is the number of channels which thanks to Mr Leese's clever trick tells us exactly which Ambisonic channels are used up to 3rd order. __________...

...nal argument. Can you please drop the additional argument and > incorporate your earlier patch that uses the struct field? That > should simplify this patch. > > Requiring the user to specify internal Ogg Opus mapping family numbers > may be okay for a quick hack to experiment with ambisonics, but > doesn't seem like the best solution for adding official support for > ambisonics in opus-tools, which is intended for use by end users. > Ideally no additional options would be needed and opusenc would be > able to identify a WAV file containing Ambix-compatible ambisonic &gt...

On 19/04/16 12:17 PM, Timothy B. Terriberry wrote: > We should probably start keeping track of the space of invalid TOC > sequences somewhere global so that people don't define conflicting > extensions. I started such a page at https://wiki.xiph.org/OpusExtensions -r -------------- next part -------------- A non-text attachment was scrubbed... Name: signature.asc Type:

..., This seems to me like it would support the ambisonic requirements you mention, though it doesn't (and I imagine won't) describe the mic locations. Somebody who actually uses that info could probably define extra header pages for a later version of this spec. I hadn't even heard of ambisonics until your post, to be honest. John oliver oli wrote: > Erik de Castro Lopo wrote: > >> f) Encoding of channel information. In a two channel file, >> is the audio data a stereo image or two distinct mono >> channels? For a file with N (> 2) channels, are th...

...;Pine.SGI.3.95L.1000710092216.9043693B-100000@turpin.york.ac.uk> Message-ID: <Pine.SOL.3.95L.1000710144201.18737A-100000@mailer.york.ac.uk> MIME-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII Hi, Rob Fletcher forwarded this to me as one of the researchers most involved in Ambisonics currently. I am, at this moment, developing a set of new subcommands for the Snack audio extension to Tcl/Tk which handle Ambisonic panning, soundfield manipulation, decoding and mixing. The panning one is almost finished and the others should follow soon after. It has proved unbelievable easy to w...