Linux-audio-dev April 2006

linux-audio-dev@lists.linuxaudio.org

99 participants
74 discussions

[linux-audio-dev] [ot] How do GUI-libs notify the program of changes?

by Julien Claassen

Hi all! I know it's completely OT, but I think there maybe people here, who could help me. Problem is: I'm still on my libcui (character user interface) project and I wonder: I push a button, slide a slider... How does the UI notify the program of this change? How do Engine and UI communicate? Please anyone: HELP ME! Kindest regards Julien -------- Music was my first love and it will be my last (John Miles) ======== FIND MY WEB-PROJECT AT: ======== http://ltsb.sourceforge.net - the Linux TextBased Studio guide

18 years, 8 months

[linux-audio-dev] Measuring playback and capture quality.

by James Courtier-Dutton

Hi, Are there any linux tools out there that will sample the line in, and display a detailed spectrum scope of the detected sound? E.g. http://www.pcavtech.com/soundcards/ct462048/SNR_LB_FS.gif Eventually I wish to send a test signal from one sound card to another and compare the frequency response/noise etc. of the line input of the card. James

18 years, 8 months

[linux-audio-dev] Linux Audio Wiki on port 2500 no more

by Hans Fugal

The wiki that was at http://fugal.net:2500 is no longer there. It now has its own subdomain: http://lawiki.fugal.net I would be perfectly happy to entertain a more dedicated domain name, or more appropriate subdomain of an existing domain, if someone wants to foot the bill. If I can figure out how in a short amount of time, I'll put up a redirect at the old address. -- Hans Fugal ; http://hans.fugal.net There's nothing remarkable about it. All one has to do is hit the right keys at the right time and the instrument plays itself. -- Johann Sebastian Bach

18 years, 8 months

[linux-audio-dev] [ANN] netjack-0.11rc5

by torbenh＠gmx.de

netjack-0.11rc5 Some pieces of Code which can deliver you the full jackd experience with multiple Computers. Links JackPorts via generic IP networks. The alsa_in and alsa_out client can connect jackd to an unrelated alsa Soundcard. And their algorithm has been improved. Also downsampling and bitrate reduction is included now, to make it work on low bitrate links. Tested over the Internet some times now, with moderate success. Also compiles on OSX... with-alsa=0 -- torben Hohn http://galan.sourceforge.net -- The graphical Audio language

18 years, 8 months

[linux-audio-dev] GPL Audio Hardware

by Richard Smith

The following post came across the the Open graphics list from one of the founders of the project looking for other things to do with the technology they have developed. I thought I'd post it here. Anyone interested should contact Tim. For anyone who dosen't know what OGD1 is see: http://kerneltrap.org/node/6262 I would think that with a little guidence from this list and tight integration with ardour and jack that a _really_ kicking pro audio setup could be produced. ============= From: Timothy Miller <theosib(a)gmail.com> To: ogml <open-graphics(a)duskglow.com> Since we're having a bit of a lull in the discussions on OGML, I thought I might start off a discussion about some ideas I've had that would benefit the Linux community as well as give OGP and Traversal a boost financially. The Open Graphics Project has gotten everyone involved a lot of attention. While it's still possible to get graphics cards supported by open source drivers, that supply is dwinding. At the rate things are going, we'll soon have no choices left. Politically and socially, the OGP is a great idea. Economically, however, it's entirely a different story. Because of the development and costs involved, low-end graphics is actually not such a great place to start. The attention we get because we want to do graphics is a major driving force, but there are much better ways to get our stream of funds started. One such idea that's been brought up before is ultra high end audio. The low-end is solved; it's called AC97 and is found in every PC chipset you can buy today. But imagine taking what would normally cost tens to hundreds of thousands of dollars in audio recording and production equipment and applying the open source model to it. Designing and producing a low-end commodity product is hard. But designing a niche audio product that sold competitively for thousands of dollars is relatively easy to pull off. To begin with, we now become much less cost-sensitive for parts, so the end product can be FPGA-based. That makes OGD1 an ideal development platform for a new audio device; in fact, it's major overkill. Once the new design is finished, we'd mass-produce a new board using a smaller FPGA and include all of the audio I/O hardware directly on-board. I know basically nothing about audio technology. But given what little I do know, here are some things that I think would be relatively easy to do with OGD1 and, what shall we call it, OAC1: - 60+ audio channels (pick your combination of in and out) - (A specialized card could handle lots more channels) - 24-bit precision per channel - Sample rates in the hundreds of kilohertz - Thousands of audio samples and MIDI instruments - Sample-based and algorithmically-generated sound-effects - Fourier analysis, band filters, mixing, and other sorts of math stuff that if I could name it, you'd be impressed - Noise-free signals (because we have experience with graphics) - Accelerated "3D sound" - Accelerated compression/decompression - Lots of other things Given hardware acceleration for most parts of audio processing, plus some excellent piece of open source sound studio software, I don't see why we couldn't produce a combination that is as good as or better than what you find in music recording studios, television stations, and every other place where you might find a need for this. Imagine how much money this could save musicians. The only thing we can't provide is the recording room with the proper accoustics. If a reduced version of the card sold for $1000, we'd have more than a few gamers and multimedia enthusiasts buying it for their 50-speaker surround-sound reality-immersion systems. Were such a project started, I would have to carefully tune my involvement. Since Howard, Andy, and I do not have a background in audio technology, it would probably be best for someone with appropriate experience to lead. But if the community can spec this product and help us design it (we can put into hardware any algorithm you specify), Traversal can produce it. The whole project, from start to finish, would be developed under GPL. This would be quite a major effort, due to the requirement for more than just drivers. Unlike the OGP, which started out of a corporation and has retained some of that flavor, the OAP would have to organize itself and push itself along. In my mind, the first major problem is getting the right people in the community together to develop the specs. So, what do you all think of this idea? Comments? Suggestions? Discussion! :) ================== -- Richard A. Smith

18 years, 8 months

[linux-audio-dev] liblo: restarting the server thread

by Dave Griffiths

Hi all, I'm trying to restart a liblo thread with the same port, but something seems to being kept hold of, as it fails (this may be intentional though). I have a test case here - am I being daft, or should this work: ---8<--- #include <stdio.h> #include <lo/lo.h> void handler(int num, const char *msg, const char *path) { printf("liblo server error %d\n",num); } int main() { printf("once\n"); lo_server_thread thr = lo_server_thread_new("4444",handler); lo_server_thread_start(thr); lo_server_thread_stop(thr); lo_server_thread_free(thr); printf("twice\n"); thr = lo_server_thread_new("4444",handler); } --->8--- I get the output: once twice liblo server error 9904 cheers, dave

18 years, 8 months

[linux-audio-dev] EMU 1212M

by Dmitry Baikov

On 4/6/06, James Courtier-Dutton <James(a)superbug.co.uk> wrote: > Creative have actually donated an X-Fi and an EMU1212M to me. > No datasheets, but at least having the hardware is a start. (Creative > pass me some datasheets for other cards though) > I have currently got as far as horrible noises coming from the EMU1212M. So, does it mean that soon we'll have linux drivers for Emu 1212, 1616 and 1818? Regards, Dmitry.

18 years, 8 months

[linux-audio-dev] fast linear resampling on ARM - suggestions?

by Tobias Scharnberg

Hello List, I'm trying to find a library or code-snippet in order to do audio resampling from 8khz to 44,1khz and from 44,1khz to 8khz. I need to resample the data in realtime - resampling a buffer of data, not a soundfile. The quality doesn't need to be good so I guess the best solution might be linear audio resampling. The device to do the resampling on is an ARM CM-X255 running at 400MHz. I tried out libsamplerate so far but when I tested it with the soundfile conversion test program it needed 3,5 secs to sample from 8kHz to 44,1 khz for a 1,7 secs audiofile - which is too slow for me. Is there something faster that can do the job? Any suggestions are highly welcome Greetings, Tobias

18 years, 8 months

Re: [linux-audio-dev] Re: GPL Audio Hardware

by Sampo Savolainen

Quoting Dave Robillard <drobilla(a)connect.carleton.ca>: > On Tue, 2006-04-04 at 13:22 +1000, Loki Davison wrote: > * At least 1 ADAT Lightpipe in/out I'd vote for at least 4 ADAT inputs so you could connect two 8 channel preamps using 88.2k or 96k to the device. ;) Sampo

18 years, 8 months

[linux-audio-dev] Re: [linux-audio-user] regarding the 2nd Book Of Linux Music & Sound

by Dave Phillips

Greetings: First, thank you to everyone who responded to my original query. I now have a much better idea how I want to do this project. I definitely want to involve members of this group. Some of you have offered to take on particular chapters, and that seems to me the best approach. I believe we can complete the work in record time by spreading the work around. I'll speak with my publisher about this plan. If he approves this approach we'll start work immediately. Some respondents wrote to me off-list and have offered to assist. I'll be in touch with you all after talking with Bill Pollock. If Bill gives us a green light I'll start organizing the distribution of work immediately. I'll communicate directly with you regarding style preferences, format requirements, deadlines, etc. I must emphasize that this project is commercial work, i.e., we'll have editors at the publishing house and there will be demands that certain dates be met. Please, only take on the work if you're sure you can work under those conditions. If the community approach is accepted I'll post a list of topics and areas that need attention. I have a large amount of unedited/incomplete material that I'm willing to offer as starting points. I've been thinking about the royalties issue. I'm far from a final plan, but I think it might be possible to route some (all?) of the royalties to the Linux Audio Consortium. The community can then decide how to use it. I can't leave this issue vague, my publisher will need to know who is in charge of accounts receivable, and I can't simply accept contributions from the community and not reimburse those contributors. How that reimbursement takes place can be left to the individual contributors, or we may decide to simply throw everything in one direction (e.g. linuxaudio.org). Btw, I especially appreciate the community's response re: the 2.4 kernel series. It is laid to rest, there will be coverage only from kernel 2.6 upwards. Thank goodness. No Starch has already accepted my outline for the project. At some point I'll post that outline on the Web for the community to consider. However, please bear in mind that there will be limitations of space and scope. I'm unlikely to be able to cover games, consumer devices, or telephony. Alas, material for a programmer's guide will probably not be accepted. IMO that really requires a separate book now. A developer's guide to ALSA and JACK is certainly timely and needed, but I'm not the one to write that book. Again, if you're interested in writing for this project please contact me off-list. Specify your area of interest and we'll go from there. Best regards, dp

18 years, 8 months

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Linux-audio-dev April 2006