Linux-audio-dev September 2004

linux-audio-dev@lists.linuxaudio.org

90 participants
77 discussions

[linux-audio-dev] This better not be patented...

by Paul Winkler

Not sure how many algorithms this makes sense for but if it works as advertised for convolution, it would make a hell of a reverb. http://www.tomshardware.com/hardnews/20040902_135943.html -- Paul Winkler http://www.slinkp.com

20 years, 6 months

[linux-audio-dev] Audio Processing on Your Graphics Card?

by Levi D. Burton

http://slashdot.org/articles/04/09/03/158210.shtml?tid=152&tid=13 "BionicFX has announced Audio Video EXchange (AVEX), a technology that transforms real-time audio into video and performs audio effect processing on the GPU of your NVIDIA 3D video card, the latest of which are apparently capable of more than 40 gigaflops of processing power compared to less than 6 gigaflops on Intel and AMD CPUs." -- Levi D. Burton http://www.puresimplicity.net/~ldb/

20 years, 6 months

[linux-audio-dev] [ANN] Aqualung, a new music player for GNU/Linux

by Tom Szilagyi

Hi all, I am pleased to announce the first beta release (and the first public release, as well) of Aqualung, a music player for GNU/Linux -------------------------------------- Homepage: http://aqualung.sf.net Aqualung is a new music player for the GNU/Linux operating system. It plays audio files from your filesystem and has the feature of inserting _no_gaps_ between adjacent tracks. Aqualung is released under the GNU General Public License. Features at a glance ==================== Supported file formats: * Almost all sample-based, uncompressed formats (eg. WAV, AIFF, AU etc.), files encoded with FLAC (the Free Lossless Audio Codec), Ogg Vorbis and MPEG Audio files (including, but not limited to, MP3) are supported. Naturally, any of these files can be mono or stereo. Supported output devices: * OSS and ALSA driver interface, as well as support for connecting to the JACK Audio Connection Kit. Key features: * Continuous, gap-free playback of consecutive tracks! Your ears get exactly what is in the files -- no silence inserted in between. * Ability to convert sample rates between the input file and the output device, in high quality. (Thanks to libsamplerate!) * LADSPA plugin support -- you can use any suitable LADSPA plugin to enhance the music you are listening to. Some other niceties: * Internally working volume and balance controls (not touching the soundcard mixer). * Support for multiple skins; changing them is possible at any time. * Support for random seeking during playback. * Track repeat, List repeat and Shuffle mode (besides normal playback) * All windows are sizable. You can stretch the main window horizontally for more accurate seeking. * State persistence via XML config files. Aqualung will come up in the same state as it was when you closed it, including playback modes, volume & balance settings, currently processing LADSPA plugins, window sizes, positions & visibility, and other miscellaneous options. In addition to all this, Aqualung comes with a Music Store that is an XML-based music database, capable of storing various metadata about music on your computer (including, but not limited to, the names of artists, and the titles of records and tracks). This is much more efficient than the all-in-one Winamp/XMMS playlist. Hope you will like this program. Please report any problems. Tom

20 years, 7 months

[linux-audio-dev] Re: [announce] [patch] Voluntary Kernel Preemption Patch

by Andrew Morton

Ingo Molnar <mingo(a)elte.hu> wrote: > > I took a > look at latencies and indeed 2.6.7 is pretty bad - latencies up to 50 > msec (!) can be easily triggered using common workloads, on fast 2GHz+ > x86 system - even when using the fully preemptible kernel! What were those workloads? Certainly 2.6+preempt is not as good as 2.4+LL at this time, but 2.6 isn't too bad either. Even under heavy filesystem load it's hard to exceed a 0.5 millisecond holdoff. There are still a few problem in the ext3 checkpoint buffer handling, but those seem pretty hard to hit. I doubt if the `Jack' testers were running `dbench 1000' during their testing. All of which makes me suspect that the problems which the `Jack' testers saw were not directly related to long periods of non-preemption in-kernel. At least, not in core kernel/fs/mm code. There have been problem in the past in places like i2c drivers, fbdev scrolling, etc. What we need to do is to encourage audio testers to use ALSA drivers, to enable CONFIG_SND_DEBUG in the kernel build and to set /proc/asound/*/*/xrun_debug and to send us the traces which result from underruns. As for the patch, well, sprinkling rescheduling points everywhere is still not the preferred approach. But adding more might_sleep() checks is a sneaky way of making it more attractive ;) Minor point: this: cond_resched(); function_which_might_sleep(); is less efficient than function_which_might_sleep(); cond_resched(); because if function_which_might_sleep() _does_ sleep, need_resched() will likely be false when we hit cond_resched(), thus saving a context switch. Unfortunately, might_sleep() calls tend to go at the entry to functions, whereas cond_resched() calls should be neat the exit point, or inside loop bodies.

20 years, 7 months

[linux-audio-dev] Re: OSC vs MIDI

by Kjetil Svalastog Matheussen <k.s.matheussen＠notam02.no>

Dave Robillard: > On Wed, 2004-09-01 at 07:48, martin rumori wrote: >> On Wed, Sep 01, 2004 at 11:31:01AM +0100, Steve Harris wrote: >> > On Wed, Sep 01, 2004 at 10:03:18 +0100, Dave Griffiths wrote: >> > > so if I'm writing a osc sequencer, is the best plan to leave the >> > > mapping open for the user to modify? >> > >> > I would say so yes, its possible that an OSC schema spe will be >> > standardised at soem point that would make it easier. >> >> not to mention the microtone-capabilities of your osc sequencer and >> the sophisticated envelope control functions, which are hard to cover >> with pure midi... :-)) > > Imagine a sequencer where, instead of little straight bars representing > notes, the 'piano roll' just allowed you to draw a line to represent > frequency.. with any angle, straight or curved (bezier), etc. Wow.. > > Control could be like that too, with overlay and everything, but having > that for pitch would be amazing.. has something like this ever been done > before? > You can draw lines to represent pitch (and everything else) in Radium, but its not a piano-roll though. http://www.notam02.no/radium/ (latest linux-(not-finished)-version: http://www.notam02.no/arkiv/src/)

20 years, 7 months

[linux-audio-dev] audio stream (stereo)

by Kachalov Anton

Hi guys, I'm coding a software implementation of a buffer for PIO-DA16 (icpdas). I'd like to know what a stream of stereo PCM data looks like and how a Digital-toAnalog-Converter understands, which part of data belongs to which channel in a stereo PCM stream. Rgds, Anton

20 years, 7 months

[linux-audio-dev] Howto grab keys?

by Pamplemousse_mk2

Hello, I'm using PortAudio library to try to program a loop-sampler software under Linux (and perhaps Windows). Actually, I would like to make a console-based software. I would like to know how could I manage entries from keyboards. I think that ncurses lib is a good choice. But my problem is in algorithm term. I think that making a code in the main() like this: while (true) { if (key is pressed) { switch (value of the key) { case 'A': proceed to FFT ; break; case 'B': proceed to time stretch break; case 'C: reduce volume break; ... ... } } wait for a certain time; } is not a good idea. I know that with MFC there is event management with WM messages. I don't know what is there under Linux, especially in console-based apps. With GUI libs like GTK, no problems I think. But what about console-based apps? Does anybody knows some internet sites, or some other libraries, or some methods (perhaps multithreads? seems to be heavy for just event managements...). I have look at ncurses docs but they shows an example with a kind of loop like the one I just talk about above. Any advice is welcome Bye.

20 years, 7 months

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Linux-audio-dev September 2004