Linux-audio-dev April 2008

linux-audio-dev@lists.linuxaudio.org

33 participants
20 discussions

by Fons Adriaensen

Hello all, Some updates on <http://www.kokkinizita.net/linuxaudio/downloads>: jmeters-0.2.0 - VU-meter scale replaced by a new one which does not have the -20dB threshold. Now it will also move for low-level sounds, and fall back much more naturally. - PPM now has the same size as VU. Old one still available as ppm2. - Added options to set jack client name and update rate. - Bugfix for Makefile, PNGs now get installed in $(PREFIX)/share instead of /usr/share. aeolus-0.8.1 - Aeolus-0.8.0 added Midi over Jack support but was announced on the Aeolus list only IIRC. With 0.8.1 it's official. - Major cleanup and bugfixes. - Replaces 0.6.6. as the supported release. ambdec-0.2.0 - Bugfixes, new collection of config files. MCP-plugins-0.4.0 - Major cleanup (after 5 years or so). - Added triple chorus. Same as chorus2 but has three outputs. Pan L,C,R for a nice stereo effect. clthreads-2.4.0 - Cleanup. clxclient-3.6.1 - Cleanup. - Probably fixes a bug that occurs only when running in KDE (windows not repainting when exposed). Many thanks to all who contributed by providing feedback, bug reports and patches. The two libs and ambdec now also have an OSX Makefile and the necessary #ifdefs to make them compile. This is very experimental. I will provide *no* support for this except to OSX developers who can provide the required technical feedback. Ciao, -- FA Laboratorio di Acustica ed Elettroacustica Parma, Italia Lascia la spina, cogli la rosa.

16 years, 11 months

LADSPA plugin behavior and naming, and more general questions

by Justin Smith

As a learning exercise, I made a LADSPA plugin that adds its inputs. I figured it would be reasonable to call such a thing '+'. Some plugin hosts don't like that (I was less surprised by the ones that could not handle the name '<'). This is the LADSPA_Descriptor.Label property. ladspa.h says "Labels must not contain white-space characters.". Is it unreasonable to expect to be able to have symbols as plugin labels, or parts of plugin labels? So this is more of a "what do you think" then a right/wrong answer kind of thing. Also, though ladspa.h does not say I cannot write my plugin library in such a way as to create resources shared by all the instances of my plugins within one host (say, a shared OSC connection?), would that be acceptable? Would that break hosts? What about per plugin GUI? If I just made a Makefile variable for a GUI to launch for a ladspa plugin, if I did not want the overhead of the full DSSI interface (or if I wanted to use the plugin in a non DSSI compatible host), would that be beyond the pale for a LADSPA plugin? Also, now that GMPI seems all but officially dead, does anyone think DSSI will be supplanted (or "disposed of", as its name would imply)? What is the general developer feeling regarding LADSPA/DSSI/LV2? I leave VST out of this list, because I don't think Linux distros can even legally distribute vst.h.

16 years, 11 months

Calibrating sound cards

by James Courtier-Dutton

Hi, Is there a recognized method for calibrating a sound card? e.g. For Playback, one sends a sample .wav PCM file to the sound card, then measure the analog output from the line-out. If the sound card itself provides 0dB of Gain, what should be the measured figure? Can this be done with a simple AC volt meter? There seems to be some debate, with regards to ALSA, as to whether the line-out is at the correct level if one sets all the ALSA mixer controls to 0dB. James

16 years, 11 months

audio meters nostalgia

by Fons Adriaensen

The first (beta) release of Jmeters is available at <http://www.kokkinizita.net/linuxaudio/downloads> Jmeters is a Jack multichannel audio level meter app. It looks very similar to meterbridge since it uses the same pixmaps. This first release offers VU, PPM and stereo versions of the same. The stereo versions have two indicator needles on the same scale. I've never seen a twin VU, but stereo (or M/S) PPMs *do* exist. Later releases will add bargraph meters, digital peak indicators for the analog ones, and a stereo correlation meter. The main difference to meterbridge is that Jmeters has the correct ballistics for both the VU and the PPM. The VU meter measures the average of the absolute value of the signal, 'average' meaning a second order filter that reaches 99% in 300ms and overshoots between 1.0 and 1.5%. It is calibrated to indicate 0dB for a sine wave at -10dB w.r.t. digital full scale (which is +/-1 peak in this case). The particular VU scale used is not entirely linear and starts at -20dB (it's one designed for a passive VU meter with a diode bridge), so the meter will not move at all for inputs below that level. Later versions may use a VU scale designed for an active meter which doesn't have this threshold. The PPM is a pseudo-peak meter. It will indicate 80% of the steady-state value for a 10ms burst, and fall by 24db in 2.8s. Each scale division (1..7) represents 4dB. It is calibrated to indicate '7' (+12 dB on the EBU scale) for 0dB FS. For speech and music with distinct short peaks the PPM will usually indicate higher. For music with continuous long notes, and for heavily compressed signals the VU indicates higher. Both meters require some 'getting used to' in order to read them correctly. You can modify the calibration by using the -g(ain) option, but it should normally not be necessary. Enjoy ! -- FA Laboratorio di Acustica ed Elettroacustica Parma, Italia Lascia la spina, cogli la rosa.

16 years, 11 months

FreeBoB 1.0.11 released (package fix)

by Pieter Palmers

The 1.0.10 package released a few weeks ago seems to have some packaging issues (missing files etc...). Therefore a new package has been uploaded that should fix these issues. Available at sourceforge: https://sourceforge.net/project/showfiles.php?group_id=117802 Greets, Pieter

16 years, 11 months

Re: [LAD] [ANN] jack_capture V0.9.10 and Snd-ls V0.9.8.16

by Jonathan Woithe

> jack_capture > : > *Added the --meterbridge / -mb option, which automatically > starts Steve Harris' meterbridge (http://plugin.org.uk/meterbridge/) > and constantly connects them to the same ports as jack_capture > is connected to. Nice - this will save me the hassle of starting meterbridge manually when setting up for recording and having to make sure that meterbridge's channels actually match jack_capture's channels. Thanks for the update! jonathan

16 years, 11 months

Re: [LAD] [LAU] new! linuxmusicians.com

by Ivica Ico Bukvic

> I'm just playing devil's advocate here, but the Linux audio community > hasn't exactly been lacking in this area: > > http://www.linuxaudio.org/ > > Is a portal to all kinds of things related to Linux audio (including > this mailing list). > > Not to mention the http://linux-sound.org/ site also. Let me take this one step further and state that the entire linux-sound.org database has been ported over into apps.linuxaudio.org with full user access to maintaining/altering the content which makes linux-sound maintenance unnecessary (esp. since Dave has effectively decided not to keep it up to date as often as he would like to). I think it would be nice if we all put efforts towards a common goal, especially since linuxaudio.org is all about the community. If there is an aspect of the lao domain you don't like, you are more than welcome to contribute... That being said, as always, we continue to be in dire need of assistance/support in making linuxaudio.org better. This is why I perceive the fragmentation of community resources to be moving us farther away from the place where we ought to be and where the consolidated online presence would be truly useful and meaningful to a community as small as ours. Best wishes, Ivica Ico Bukvic, D.M.A. Director, Linuxaudio.org Virginia Tech Dept. of Music - 0240 Blacksburg, VA 24061 (540) 231-6139 (540) 231-5034 (fax) ico(a)linuxaudio.org www.linuxadio.org

16 years, 11 months

[ANN] jack_capture V0.9.10 and Snd-ls V0.9.8.16

by Kjetil S. Matheussen

jack_capture ============ jack_capture is a program for recording soundfiles with jack. Its default operation is to capture whatever sound is going out to your speakers into a file. (But it can do a number of other operations as well...) Screenshot: http://www.notam02.no/arkiv/src/jack_capture.png http://www.notam02.no/arkiv/src/?M=D 0.9.7 -> 0.9.10: *Fixed segfault in case the --channels / -c argument is higher than the number of ports which is possible to connect to. *Added a terminal vu meter by default. It'll also display red in case the recorded jack value is equal to or higher than 1.0. Use "-dv" to disable. *Added the --meterbridge / -mb option, which automatically starts Steve Harris' meterbridge (http://plugin.org.uk/meterbridge/) and constantly connects them to the same ports as jack_capture is connected to. *Added the --write-to-stdout / -ws option which writes 16 bit little endian sound to stdout. Code made by looking at jack-stdout.c by Robin Gareus. *Added the --print-formats / -pf option. *Replaced jack_client_new() with jack_client_open() Snd-ls V0.9.8.16 ================ Snd-ls is a distribution of Bill Schottstaedt's sound editor SND. (http://ccrma.stanford.edu/software/snd/) Its target is people that don't know scheme very well, and don't want to spend too much time configuring Snd. It can also serve as a quick introduction to Snd and how it can be set up. Snd-ls also serves as base code for the San-Dysth softsynth (http://www.notam02.no/~kjetism/sandysth/) and the Snd-rt music programming language (http://www.notam02.no/arkiv/doc/snd-rt) http://www.notam02.no/arkiv/src/snd/ 0.9.8.13 -> 0.9.8.16: *Fixed definstrument and faust. *Removed deprecated CAIRO_FONT_TYPE_ATSUI *Updated <slider> in snd-rt, <slider> in gui. (bugs reported by "border") *Fixed definstrument. *Replaced jack_client_new with jack_client_open

16 years, 12 months

[ANNOUNCE] pytagsfs version 0.6.0

by Forest Bond

Hi, [I've sent this message to several large mailing lists. Please be sure any replies don't get sent to all of them, i.e. don't use the Reply-to-all feature of your mail client.] I'm pleased to announce the release of pytagsfs version 0.6.0. This release includes significant enhancements as well as critical bug fixes: * Support for mkdir/rmdir. * Improved performance for readdir. This makes directory listings faster. * Fix for broken stat result caching. This bug would have caused significant performance problems. * Fix for incorrect directory timestamps. * Fix for bad handling of updates to previously unrepresentable source files. This bug would cause files to not appear under the mount tree when tagged. * Fix for incompatibility with version 0.2 of the Python FUSE bindings. Thanks to Chris Pickel and Jeremy Jones for reporting bugs and testing fixes. The full set of changes for this release is available: http://www.pytagsfs.org/Changelogs/0.6.0 To download this release: http://www.pytagsfs.org/Download pytagsfs is a FUSE filesystem that arranges media files in a virtual directory structure based on the file tags. For instance, a set of audio files could be mapped to a new directory structure organizing them hierarchically by album, genre, release date, etc. File tags can be changed by moving and renaming virtual files and directories. The virtual files can also be modified directly, and, of course, can be opened and played just like regular files. For a more thorough introduction, see: http://www.pytagsfs.org/Introduction Please visit http://www.pytagsfs.org to obtain more information. Feel free to contact me with any questions. Feedback is appreciated. Thanks, Forest -- Forest Bond http://www.alittletooquiet.net http://www.pytagsfs.org

16 years, 12 months

FreeBoB 1.0.10 released

by Pieter Palmers

Not an April's fool, but for real: libfreebob 1.0.10 has been released. This maintenance release addresses the following: - Add a configure option to disable the samplerate setting at startup. This enables the use of e.g. the Focusrite Saffire Pro with FreeBoB. - implement clipping - generate an xrun when a dropped packet has been detected Available at sourceforge: https://sourceforge.net/project/showfiles.php?group_id=117802 Upgrade if you feel like doing so. If all is fine, don't. Greets, Pieter

17 years

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Linux-audio-dev April 2008