[whatwg] Audio Panning - Bump
Hello, A Google search on the discussion list returns the unanswered question from Keith Bauer (http://lists.whatwg.org/htdig.cgi/whatwg-whatwg.org/2009-December/024340.html) below. I'm working on an application which has two separate channels of sound panned fully left and right in a stereo audio file. The application is for language learners and it would be very useful to set the audio pan position fully left or right to effectively mute one speaker. As the draft spec stands the only solution that presents itself is to split the stereo file into two and load two audio elements in the HTML. I haven't tried this yet but I suspect it will be a headache. Any chance of reviving panning? Keith Bauer onesadcookie at gmail.com Sat Dec 5 17:19:59 PST 2009 It looks in the current draft spec as if audio is not pannable, and from Googling it looks like this was at one point considered, but I can't find an explanation as to what happened between then and now. Obviously panning is problematic for stereo audio, but with Canvas and WebGL making browser games more possible, having the ability to pan at least mono audio seems like a worthwhile addition. Or is WebGL to be followed shortly by WebAL ;) -Keith [see also - http://lists.whatwg.org/pipermail/whatwg-whatwg.org/2007-March/010231.html] -- Eoin Kilfeather Digital Media Centre Dublin Institute of Technology
Re: [whatwg] Dealing with Stereoscopic displays
Hi Rob, all, Fair enough :-) I'll have to try better. Rob you give some good examples (WebGL and CSS3) of how an application could be built which correctly renders two views with stereopsis. However, with the exception of Anaglyph methods, a user will need specialised display hardware to properly view the image. So, to clarify, the issue is not the rendering of the stereo views (I'll worry about that later) but rather how those views are targeted to the correct virtual display (for example by alternating the left and right views on odd and even frames). If we take the case of the Blu-Ray 3D specification it is neutral about how the hardware is implemented, but the hardware is expected to respect the flags indicating whether a frame is for the left or right virtual display. In order to work with HTML the UA has to have some awareness of the hardware and way of signalling with view is for which virtual display. My question is, how can this be done in a consistent manner? Given that this usually requires some hardware control, is a good approach to use the device element? I hope this is a little clearer. Best regards, Eoin. On Tue, Apr 27, 2010 at 10:01 AM, Robert O'Callahan rob...@ocallahan.orgwrote: On Tue, Apr 27, 2010 at 8:38 PM, Eoin Kilfeather ekilfeat...@dmc.dit.iewrote: * A user visits the National Museum site and wants to see a time-machine view of objects in the collection with a sense of 3D depth based on their age I think this is the closest you get to an actual use-case :-). The rest is mixed up with information about possible solutions. Also, it's highly unlikely the a user will visit your site with a fully formed desire to view objects in a collection with a sense of 3D depth based on their age :-). But let's say the authors of that site want to visualize objects in the collection with different objects at different depths. It seems to me either WebGL or CSS 3D transforms --- or a mixture --- could be used for this, maybe with some extra information provided to identity the camera positions for rendering the stereo views. Actually, I probably shouldn't be involved in this discussion since I'm monocular :-). Rob -- He was pierced for our transgressions, he was crushed for our iniquities; the punishment that brought us peace was upon him, and by his wounds we are healed. We all, like sheep, have gone astray, each of us has turned to his own way; and the LORD has laid on him the iniquity of us all. [Isaiah 53:5-6] -- Eoin Kilfeather Digital Media Centre Dublin Institute of Technology
Re: [whatwg] Dealing with Stereoscopic displays
Well, I agree that the web author shouldn't worry about how it is achieved, but would it not be the case that the author needs to indicate which view is for which display? That is to say the author would be required to flag the output for correct routing to the virtual display. Is it beyond the scope to the specification to indicate a normative way of doing this? Best, Eoin On Wed, Apr 28, 2010 at 9:17 AM, Robert O'Callahan rob...@ocallahan.orgwrote: On Wed, Apr 28, 2010 at 8:09 PM, Eoin Kilfeather ekilfeat...@dmc.dit.iewrote: If we take the case of the Blu-Ray 3D specification it is neutral about how the hardware is implemented, but the hardware is expected to respect the flags indicating whether a frame is for the left or right virtual display. In order to work with HTML the UA has to have some awareness of the hardware and way of signalling with view is for which virtual display. Sure, but this seems like a UA-specific issue that the Web author should not need to worry about. UAs already coordinate with the underlying software and hardware platform to render Web content. Rob -- He was pierced for our transgressions, he was crushed for our iniquities; the punishment that brought us peace was upon him, and by his wounds we are healed. We all, like sheep, have gone astray, each of us has turned to his own way; and the LORD has laid on him the iniquity of us all. [Isaiah 53:5-6] -- Eoin Kilfeather Digital Media Centre Dublin Institute of Technology
Re: [whatwg] Dealing with Stereoscopic displays
Hi again, Thanks for the replies and informed feedback. I wasn't fully aware of the significance of the replicate proposal, and I like what it potential offers for my use case, but the hardware control problem remains. Essentially the UC is this; USE CASE: A web developer wants to utilise the next generation of stereoscopic displays (for arguments sake we assume that these are going to become ubiquitous as quickly as LCD flat-screens did) for UIs which create an impression of depth (coverflows, time-machines, head-up-displays, etc.) SCENARIOS: * A user visits the National Museum site and wants to see a time-machine view of objects in the collection with a sense of 3D depth based on their age * Her PC is connected to a stereoscopic screen but the web application can't know the details of the implementation: Anaglyph glasses, polarising glasses, lenticular cover etc. * The web page has a device selector with type = stereo_display (?) which detects / gives access to the stereo functions of the display - i.e. turns on whatever feature gives stereopsis * The UA has awareness of a left and right render path for two widows / documents but knows that these are stereoscopically linked (is this sensible ?) * The web application now has two render targets * The web application now generates slightly different left eye and right eye views * The UA renders the two documents in the correct window REQUIREMENTS: * Stereo displays should be discoverable (through device ?) * Stereo displays should be controllable by the UA (again through device ?). * Scripts should have access to both render targets Any suggestions / criticisms? Regards, Eoin. On Tue, Apr 27, 2010 at 3:15 AM, ddailey ddai...@zoominternet.net wrote: No it isn't simple. Allied issues have been discussed here before. As the nature of input devices become richer (e.g. eye movement glasses that give binocular disparity data to the display device) then the nature of the convergence data that defines the scene becomes more relevant to its primary semantics. As SVG and 3D technologies begin to bridge the gap between 2 and 3D (cf. the replicate proposal [1] or [2] ) the distinction between styling and markup so tenaciously held in HTML may cease to be so clearcut. cheers David [1] http://old.nabble.com/A-proposal-for-declaritive-drawing-(%3Creplicate%3E)-to-be-added-into--SVG-td28155426.html [2] http://srufaculty.sru.edu/david.dailey/svg/SVGOpen2010/replicate.htm - Original Message - From: David Singer sin...@apple.com To: whatwg@lists.whatwg.org Sent: Monday, April 26, 2010 8:02 PM Subject: Re: [whatwg] Dealing with Stereoscopic displays I agree that this probably means that web elements that are 'flat' would be styled by CSS with a depth. This is important if other material presented to the user really is stereo (e.g. a left/right eye coded movie). The movie will be set so that the eyes are expected to have a certain 'convergence' (i.e. they are looking slightly inward towards some point) and it's important that if material is overlaid on that. it has the same convergence. Obviously, this is unlike the real world where focus distance and convergence distance are the same (focus distance is fixed at the screen distance), but the brain can get very confused if two things that are both in focus are at difference convergence distances. This is not a simple question, as I expect you are beginning to realize. David Singer Multimedia and Software Standards, Apple Inc. -- Eoin Kilfeather Digital Media Centre Dublin Institute of Technology Aungier Street Dublin 2 m. +353 87 2235928 skype:ekilfeather
[whatwg] Dealing with Stereoscopic displays
Hello, I was wondering if any though had been given to a consistant way of dealing with stereoscopic displays. A use case has come up in a project I am working on which calls for the use of stereoscopic UIs but I can find no metion of the term in either the specs or the mailing list archive. My though was that perhaps it could be achieved by having a browsing context _left_display or _right_display allowing the user agent would render the left/right eye views to the correct display in a technology agnostic way. Apologies if this has already been covered. Eoin. -- Eoin Kilfeather Digital Media Centre Dublin Institute of Technology Aungier Street Dublin 2
Re: [whatwg] Video Tag Proposal
Forgive my ignorance, I Am Not A Lawyer, but what are the consequences of a submarine patent on Theora and/or Vorbis? If a browser supports it in good faith, and subsequently a troll successfully introduces a patent challenge, would the consequence not be that the codec would simply be dropped with the next maintenance release of the browser? In fact a court would surely allow a reasonable time for transition. OK, annoying that content providers need to re-encoded in a legal codec, but that is at least a work-flow susceptible to automation. I can't see a court giving financial damages for infringement of a patent which hasn't surfaced since video was proposed at the end of 2006. On Mon, Mar 29, 2010 at 10:23 AM, David Gerard dger...@gmail.com wrote: On 29 March 2010 09:41, Kit Grose k...@iqmultimedia.com.au wrote: Apple is at heart a hardware company. My understanding of their objections to OGG have been also largely due to a lack of hardware decoder support in their iPods/iPhones. No, they claimed submarine patents as their actual objection to Theora. (I'm not aware of them making an express claim of this sort regarding Vorbis.) - d. -- Eoin Kilfeather Digital Media Centre Dublin Institute of Technology Aungier Street Dublin 2 m. +353 87 2235928 skype:ekilfeather
