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Real-time Audio Processing and Streaming
by Richard Lewis 26 May '06

26 May '06

Hello ALUG, I'm doing some work with one of the post-grads on a Web-based audio mixer for live sound sources. The user will see each of the, say, half-dozen sound sources arranged on the screen and as he moves his cursor (or "joystick") towards one, it becomes predominant in the mix. Each of the sound sources will play either a continuous stream from a live microphone or continuous loops of interesting cached sounds. My basic plan is to have this sort of "joystick" metaphor on the client side which responds to mouse gestures by sending lots of small HTTP requests representing Open Sound Control commands using AJAX to a PHP (or possibly the dreaded Perl) script on the server side which, in turn, forwards the OSC commands to the mixer software. The output audio stream from the mixer should then be MP3 encoded and streamed back to the client to play in his embedded media player. I have a clear view of how I will implement everything up to and including the server side PHP (or Perl). After that I'm not so sure. There are two aspects that I'd appreciate anyone's wisdom on. First is the mixing software. The reason why I've mentioned OSC is because my colleague is an experienced Max/MSP user and would like to use either that or PureData to handle the mixing. However, I'm worried about how well this will scale up when multiple users are connected. Will I have to run one instance of Max (or pd) for each client connection? Should I perhaps consider a more UNIXy tool like ecasound or something? Second is the streaming software. I'm a bit surer about this: I've looked at Icecast and it seems to do MP3 encoding. I reckon it can probably handle multiple client sessions as long as each connection has its own distinguishable source audio stream which I suppose depends on how I choose to implement the mixer. Has anyone had any experience with it? Is it very resource intensive? Any thoughts or experiences would be very welcome! Cheers, Richard -- -=-=-=-=-=-=-=-=-=-=-=-=-=- Richard Lewis Sonic Arts Research Archive http://www.sara.uea.ac.uk/ -=-=-=-=-=-=-=-=-=-=-=-=-=-

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Would anyone care to Samba?
by Barry Samuels 25 May '06

25 May '06

I have an IBM ThinkPad R51 less than a year old which came with Windows XP although I have Debian installed on it which is what I mostly use. However there is one Windows application, MapInfo, which I use occasionally and for which I have never found a Linux substitute. I had the laptop set up to connect to my normal Linux (Debian Testing) desktop machine via Samba and was able to use it. Then two things happend. 1. I moved the mount point of the partition on the Linux machine to which the laptop, running Windows, connected. I changed the paths in smbd.conf and did think to restart Samba. 2. I also upgraded Debian Testing on my non-laptop machine. Now the laptop won't even recognise that the Debian machine is there although it is connected to the network and I can ping the Debian machine. My first thought was to look in the logs on the Debian machine for errors but there are no errors! Where do I go from here to find which machine is the cause of the problem? I assume it must be the Debian desktop because that's the only one that's changed. Both smbd and nmbd are running on the desktop. -- Barry Samuels http://www.beenthere-donethat.org.uk The Unofficial Guide to Great Britain

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Linux.com : Runit makes a speedy replacement for init
by Keith Watson 25 May '06

25 May '06

<http://www.linux.com/article.pl?sid=06/05/03/2126222 > ...interesting article. Does anyone use anything other than SysVinit for booting? Regards, Keith ____________ Make the most of yourself, for that is all there is to you. - Ralph Waldo Emerson

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Can someone explain?
by Ted.Harding＠nessie.mcc.ac.uk 24 May '06

24 May '06

Hi Folks, Someone out there will know the answer to my ignorant query ... Suppose I have an up-and-running internet connection via my ISP. So I telnet into a remote host (e.g. nessie.mcc.ac.uk) and establish a login-session. So far so good. Next, for DSL reasons, the internet connection is interrupted (the router re-syncs). Shortly afterwards, it is re-established again. But now, I have lost contact with the login session. My question is: What is the mechanism (or perhaps absence of mechanism) leading to losing the contact? Or, turning the question on its head, what is it that keeps my link with the remote host alive so long as the internet connection stays up? The naive version of the question: If my packets can find their way to my login to nessie before the line drops, and nessie's can find their way back to my telnet, how come they can't continue to do so after the line drops and is re-estiblished? I hope people understand what I'm asking -- I'll try better if you don't! Thanks, and best wishes to all, Ted. -------------------------------------------------------------------- E-Mail: (Ted Harding) <Ted.Harding(a)nessie.mcc.ac.uk> Fax-to-email: +44 (0)870 094 0861 Date: 24-May-06 Time: 21:03:41 ------------------------------ XFMail ------------------------------

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Why always public-key encryption algorithms?
by chrisisbd＠leary.csoft.net 23 May '06

23 May '06

Why is it that *everything* uses some sort of public-key encryption algorithm for storing sensitive data? It's stupid! OK, it's brilliantly useful for sending data across the internet and so on but for storing one's own sensitive data it is entirely pointless as far as I can see. For example if I want to store a file with some sensitive data in it and only only want to be able to decrypt it myself then surely anything *but* a public key encryption algorithm makes sense. Essentially a public key algorithm means that there is always a brute force way of getting at the data, it may take more computing power/time than is available but it is in principle possible. Other ways of encrypting can be made essentially uncrackable if you want. Are there any encryption experts here who can persuade me that I'm being silly? -- Chris Green (chrisisbd(a)leary.csoft.net)

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USB On Old Laptop
by Simon Royal 23 May '06

23 May '06

Hi I have an old laptop with no USB, a ThinkPad 380ED which has 16bit PCMCIA slots. Can anyone suggest where I would get a USB PCMCIA card from? I have searched eBay but even the great online garage sale failed to return anything. It doesn't have to be USB 2 a simple USB 1.1 card would do but all they have is cardbus cards. Kind Regards Simon Royal ---- www.simonroyal.co.uk The box said requires Windows 2000 or better, so I bought an Apple Mac

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For Sale
by Wayne Stallwood 23 May '06

23 May '06

As previously mentioned I have upgraded my home server and the old one is looking for a new home if anyone is interested. It's a converted Gigabyte NAS box. Originally it was a Linux based appliance server that offered basic filesharing, print, firewall and mail services. It's a very nicely built little unit, a tiny tower measuring about 400x300x90mm. Quiet enough to sit in the corner of a room without causing much annoyance (it is a LOT quieter than my new 1U rack server) Many moons ago it was de-commissioned at one of my clients due to hard drive failure (the original OS was lost as part of that failure) I fitted a 120GB hdd and installed Ubuntu Server. It has served me very well ever since. In fact the main reason I retired it was that I couldn't find a half height PCI line card (the only type that will fit) that would play nicely with Asterisk. It has a PIII 866 Mhz CPU 128MB of RAM (standard dimm slots, one free) 2 NIC's (so it could make a nice firewall if nothing else) 1 PCI Modem 120GB HDD (with space for another) It also has a little LCD on the front that shows POST status during startup. This was originally also controlled by the OS and showed running status as well. It is plugged into a PCI card (more on that in a mo) on what I think *may* be a parallel port. However I have never managed to get lcdproc to drive it (and can't for the moment even remember what chipset the LCD is) so at the moment it shows the post bits and then stops at "Starting operating system....." at which point the OS driver should be taking over. A brave new owner can have another go or take one of my spare hd44780 displays to try and replace it. The PCI card also has a socket for a "disk on chip" I still have the 8MB part that was in there, however this contains the bootloader for the original OS and was interfering with the Ubuntu boot so I removed it. The only slight complication is that it is a headless unit (no VGA and no PS/2 keyboard socket) When I originally set it up I got around this by taking it apart and plugging in a PCI graphics card and a USB keyboard on an internal USB header. Alternatives would be to perform a minimal installation with the drive in another machine. With this in mind I would install the new owners OS of choice and set it up for their network prior to handing it over. I am told that the Debian installer will default to ttys0 if there is no local graphics, which would make life a little easier (it has a serial port on the back panel) £80

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Secure web access to password protected data - suggestions?
by chrisisbd＠leary.csoft.net 22 May '06

22 May '06

I'm after setting up a small amount of 'secure' data on my web server that I can access and, preferably, modify via the internet using a browser. I.e. I basically want a web page (or a hierarchy of web pages) whose content is password protected. The ideal sort of interface would be a Wiki sort of approach - I think. Is there anything out there that can do this sort of thing? There are a number of PHP based password storage utilities but these are rather restictive of the format in which you can store data, I'd much prefer to be able to store free format text. There are two basic approaches as well:- Use client side decryption (i.e. Javascript or Java) so that only the encrypted data is sent over the internet. For me it wouldn't even be necessary to send the decryption code with the pages as I'm quite happy to install that on the two or three systems where I want to be able to view and modify the data. This approach has the advantage of not requiring an encrypted (https:) web server. User server side encrypt/decrypt and an https: server. This requires more effort to set up apache to do https: but I suspect is rather easier to do the actual encrypting and decrypting. In fact, given that the 'source' code lives on a fairly secure machine at home how vulnerable would the data be if it was just in a password protected Wiki? (i.e. the data itself isn't encrypted) Any and all ideas welcome. (well, except writing it down on a piece of paper and carrying that around with me) -- Chris Green (chrisisbd(a)leary.csoft.net)

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SysAdmin position
by James Green 22 May '06

22 May '06

Hi, If anyone's looking for a sys-admin position and has relevant experience, you might like to submit your CV to employment(a)stealthnet.net Job involves administering various Debian installations including production web, database and mail servers. Also involved with be a certain amount of looking after our "admin" network in Gorleston including Windows XP workstations. Although the successful candidate will find a Mac Mini on their desk should they want to use it :) We're ideally looking for 4 years experience, but 2+ will be considered. You will also be expected to take part in on-call rotas. Desirable experience: MySQL Replication Exim4 / Cyrus Bind9 PHP/Perl Windows administration CVs to: employment(a)stealthnet.net P.S. Don't look at www.stealthnet.net and believe it all - it hasn't been updated in years. Complete new version in beta! Kind regards, James Green

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RE: [alug social] Re: [ALUG] Fwd: First ALUG competition of 2006
by Keith Watson 22 May '06

22 May '06

> From: sfr Sent: 21 May 2006 12:14 > > On 20/05/06, Brett Parker <iDunno(a)sommitrealweird.co.uk> wrote: > > On Sat, May 20, 2006 at 10:07:14PM +0100, Paul > <lists(a)bulldoghome.com> wrote: > > > > > Guess Brett wants to keep the prizes all for himself... > > > > Have we ever worked out what they are yet? > > yes.. well... > > first prize is LOTS of Kudos, international fame, and a certificate. > and something else ... an early release copy of Windows Vista > > second prize is some kudos, slightly less fame, and er... > something else. > ... TWO early release copies of Windows Vista > hang on a minute, I'll look in the charity-shop box. > > -- > eli alternatively... 1st prize - the opportunity to supply Brett with pints of beer for a whole night 2nd prize - ditto (but followed but a chinese/indian take away of Brett's choice) 3rd prize - you don't want to know about the 3rd prize Regards, Keith ____________ Even before I can say it, it is no more. - Sengai

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