From: GIBBS, P. <pau...@te...> - 2003-07-31 11:18:03
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There are simple things that can be done to give a very good impression of surround sound which use little CPU (assuming decoding the signal into 4 / 5 signals is simple.) I have been considering requesting this for some time. Spacialisation techniques can be as simple as playing a sound in the opposite ear slightly delayed and quieter; A sound on you left will reach your left ear before having to go around your head to reach your right ear at a reduced volume and clarity. Sound directly infront of you will reach both ears at the same time. The delay between sound reaching ears increases with the angle that the sound is coming from. Implementing a 5 / 4 -> 2 speaker system may weald rewarding results with just these simple princpiles. left -> Left, right -> Right, Centre -> Left+Right, rearleft -> Left, rearleft -> Right(1/2 volume & delayed), rearright -> Right, rearright -> Left(1/2 volume & delayed) The delay should be in the order of 0.3m / 341m/s = 0.8ms allowing for distance down inner ear as well as around head YMMV. It is worth noting these techniques can work equally well with normal 2 speaker systems. It is even possible to widen the standard stereo image by playing the normal left/right signals much quieter and only slightly delayed on the opposite speaker. HTH Paul.<>< On Thursday, July 31, 2003 11:24 AM, Michael Roitzsch [SMTP:mr...@us...] wrote: > Hi, > > > I'm new to the list. First of all, I want to say "hello" & "thank > > you" to all the members of the Xine development team and the users' > > community. > > > > I've been "playing" with a couple of Windows' DVD players that had > > implemented Dolby Headphone encondig > > (http://www.dolby.com/dolbyheadphone/). Wow! I was amazed! > > Ok, nothing compares to the "real" 5.1 stuff, but as a user-story > > about this technology says, when you have no choice but headphones to > > listen something... then Dolby Headphone is the way to go. > > > > So I'd like to know if it would be possible to have this on Xine > > too... some day. > > I must say I'm new to the Linux sound architecture (ok... not only to > > the sound architecture...), so I really don't know if this should be > > implemented by something in the kernel, by ALSA, by OSS... > > Since this basically means digital signal processing the multichannel > signal down to stereo in some magical way, it would definitely live in > userland and not in the kernel. > > > whatever... and I don't know if this would mean paying royalties to > > the Dolby Laboratories either. > > Using the term "Dolby Headphone" certainly would. But even the basic > ideas of simulating surround sound with two channels through signal > processing might be patented by someone. > > > Can anybody explain here if this is possible, and how difficult (or > > not) it could be? > > At first someone has to find out, how these things work. And I don't > think Dolby would donate us their specs. > So unless any DSP guru writes a free virtual surround library, there is > not much we can do here. Anyone knows any such project? > > Michael > > -- > /* Host controller interrupts must not be running while calling this > * function or the penguins will get angry. */ > 2.2.16 /usr/src/linux/drivers/usb/ohci.c > > > > ------------------------------------------------------- > This SF.Net email sponsored by: Free pre-built ASP.NET sites including > Data Reports, E-commerce, Portals, and Forums are available now. > Download today and enter to win an XBOX or Visual Studio .NET. > http://aspnet.click-url.com/go/psa00100003ave/direct;at.aspnet_072303_01/01 > _______________________________________________ > xine-user mailing list > xin...@li... > https://lists.sourceforge.net/lists/listinfo/xine-user > > _____________________________________________________________________ > *** E-Mail confidentiality notice *** > This message and any attachments are intended for the addressee only. It is > private and confidential. If you have received this message in error, please > reply to this e-mail and highlight the error and then remove it from your > system. You must take no action based on this, nor must you copy or show this > to anyone. > _____________________________________________________________________ > > This message has been checked for all known viruses by Star Internet > delivered through the MessageLabs Virus Scanning Service. For further > information visit http://www.star.net.uk/stats.asp or alternatively call > Star Internet for details on the Virus Scanning Service. Paul Gibbs DDI - 01845 521024 Teleware Plc, York Road, Thirsk, YO7 3BX _____________________________________________________________________ *** E-Mail confidentiality notice *** This message and any attachments are intended for the addressee only. It is private and confidential. If you have received this message in error, please reply to this e-mail and highlight the error and then remove it from your system. You must take no action based on this, nor must you copy or show this to anyone. _____________________________________________________________________ This message has been checked for all known viruses by Star Internet delivered through the MessageLabs Virus Scanning Service. For further information visit http://www.star.net.uk/stats.asp or alternatively call Star Internet for details on the Virus Scanning Service. |