Linux-audio-dev

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4 participants
7502 discussions

by Will Godfrey

A long time ago ... in a land far away :) I did some assembler programming on the Acorn Archimedes (ARM 2/3) and worked out a series of additions and subtractions that would perform very fast multiplication of awkward numbers by known amounts. Is there any point in doing this for C programs, or are modern compilers sophisticated enough to do such things themselves? If anyone is interested *7 is: RSB R1, R0, R0, LSL #3 -- Will J Godfrey http://www.musically.me.uk Say you have a poem and I have a tune. Exchange them and we can both have a poem, a tune, and a song.

10 years, 10 months

Re: [LAD] Drivers for RME (USB) MADI device (Madiface XT)

by Jonathan Woithe

On Mon, 11 Aug 2014 15:06:24 +0200 Adrian Knoth wrote: > On 08/11/14 05:47, D. Sen wrote: > > I was advised by Paul Davis to inquire on this list whether there has > > been or is likely to be any activity in developing ALSA drivers for the > > RME Madiface XT device. Its a USB device and as such makes it very > > amenable to a portable audio work. > > > > I have used PCIe based Madiface in the past using ALSA. However, I could > > not get the USB based Madiface XT to work. The device was recognized > > correctly (as per the SYSLOG) - however no drivers were loaded. > > > > Any help would be very much appreciated. > > As I said a year ago, it should also be possible to sniff the USB > connection, but this requires a device and a volunteer to do so. You'd > then run Windows in a VM and capture the USB packets with wireshark or > any other USB sniffer. > > Jonathan Woithe may have additional information, since he wrote the > drivers for FF400 and FF800. The FF400 and FF800 are, obviously, both firewire devices. Due to the bus structure and the way it operates there will be nothing in common between this and any of the RME USB or PCIe interfaces. The drivers for the FF400 and FF800 are in FFADO, and while you may get some high level ideas from things like our mixer interface, unfortunately our existing code is unlikely to provide much in the way of direct assistance when looking at devices using other interfaces. Having gone down the protocol analysis route before (albeit not on the RME devices) what Adrian has suggested is entirely feasible for the USB variant. It will be time consuming, but sniffing the USB bus isn't difficult technically speaking and - most importantly - doesn't require special hardware now we have VMs. Obviously the ideal situation is to obtain documentation from the manufacturers, so contacting them as Adrian suggested would be worth a shot. Regards jonathan

10 years, 10 months

Update of zita-at1

by Fons Adriaensen

Zita-at1-0.4.0 is now avaliable at the usual place: <http://kokkinizita.linuxaudio.org/linuxaudio/downloads/index.html> Bugfixes, MIDI channel selection added. Ciao, -- FA A world of exhaustive, reliable metadata would be an utopia. It's also a pipe-dream, founded on self-delusion, nerd hubris and hysterically inflated market opportunities. (Cory Doctorow)

10 years, 10 months

Stoat 1.0 Release

by Mark D. McCurry

Hello all, The first release of stoat is available. Stoat is a S.T.atic (LLVM) O.bject file A.nalysis T.ool which is a rewrite of sfpv (Static Function Property Verification) due to the very quick bitrot of the clang API (stoat uses only the llvm optimizer pass API). This tool is designed to evaulate if any realtime function can end up calling a non-realtime function eg a jack process callback being able to call malloc or free. It does this by: 1) Using either inline or external function whitelists and function blacklists to establish which functions are safe and unsafe. 2) Extracting a function callgraph (including virtual function calls) from the LLVM IR representation of code (which is effectively one level above assembly) 3) Perform simple deductions based upon the callgraph This approach is designed to work best for C/C++ projects and for realtime verification, but fairly little stops it from generalizing to other languages (assuming the other languages compile with llvm) and other function properties. Existing annotations from sfpv should still work, though the only project that I've seen using them has been jalv so far. As this might seem quite abstract, here is an example usage with non-timeline: http://log.fundamental-code.com/2014/08/15/stoat-tutorial-example Project Home: https://github.com/fundamental/stoat Report bugs to: https://github.com/fundamental/stoat/issues Mark

10 years, 10 months

revisiting pulse and jackdbus

by Len Ovens

On Tue, 12 Aug 2014, Max wrote: >> Pulse on jack. > > Would you suggest that your method is better and should be the > canonical way to do pulse on jack? If so, shall we write up an > alternative WalkThrough on the jackoudio wiki that helps people > setting that up? Something more to add. If you are using a debian based distro (ubuntu for example) the jackd executable needs to be chmod -x or you will find odd things happen if you manage to crash jackdbus. Generally some well meaning program will come along and start jackd making qjackctl of no use and making module-jackdbus-detect unable to set up the pa-jack bridge. The command killall -9 jackd needs to be run. I now concider this has rissen above anoyance to bug. Jackd2 and jackdbus should be packaged separately. If needed the jackdbus version can come with a script that has jack_control's innards, but acts like jackd. (uses jackd's config file and takes jackd's arguments on the CL... may as well give it jackd's name too). For my use, all it would have to do is ignore the arguments and run jack_control start which would restart with the parameters I chose before or do nothing if it is already running. -- Len Ovens www.ovenwerks.net

10 years, 10 months

[ANN] MOD Duo's Kickstarter campaign to be launched in mid September

by Gianfranco Ceccolini

Greetings Linux Audio Users and Developers !!! I'm very happy to inform that we will launch the MOD Duo's Kickstarter campaign in mid September. The MOD Duo is our second model and we've been putting a lot of engineering in it based on the feedback we had from the MOD Quadra experience. We deeply hope it becomes a device that empowers the Linux Audio community, bringing together developers and musicians. A pre-campaign site was created to warm up the communication engines: http://stepontothefuture.com. Hope you all enjoy and spread the word Kind regards Gianfranco Ceccolini The MOD Team

10 years, 10 months

Drivers for RME (USB) MADI device (Madiface XT)

by D. Sen

Hi List-members, I was advised by Paul Davis to inquire on this list whether there has been or is likely to be any activity in developing ALSA drivers for the RME Madiface XT device. Its a USB device and as such makes it very amenable to a portable audio work. I have used PCIe based Madiface in the past using ALSA. However, I could not get the USB based Madiface XT to work. The device was recognized correctly (as per the SYSLOG) - however no drivers were loaded. Any help would be very much appreciated. Best Regards, Deep

10 years, 10 months

Constant-Q library and Vamp plugin

by Chris Cannam

Announcing a new C++ library and Vamp plugin implementing the Constant-Q transform of a time-domain signal. https://code.soundsoftware.ac.uk/projects/constant-q-cpp The Constant-Q transform is a time-to-frequency-domain transform related to the short-time Fourier transform, but with output bins spaced logarithmically in frequency, rather than linearly. The output bins are therefore linearly spaced in terms of musical pitch. The Constant-Q is useful as a preliminary transform in various other methods such as note transcription and key estimation techniques. This library provides: * Forward transform: time-domain to complex Constant-Q bins * Forward spectrogram: time-domain to interpolated Constant-Q magnitude spectrogram * Inverse transform: complex Constant-Q bins to time domain The Vamp plugin provides: * Constant-Q magnitude spectrogram with high and low frequency extents defined in Hz * Constant-Q magnitude spectrogram with high and low frequency extents defined as MIDI pitch values * Pitch chromagram obtained by folding a Constant-Q spectrogram around into a single-octave range The code is provided with full source under a liberal licence, and plugin binaries are provided for Windows, OS/X, and Linux. The method is drawn from Christian Schörkhuber and Anssi Klapuri, "Constant-Q transform toolbox for music processing", SMC 2010. See the file CITATION for details. If you use this code in research work, please cite this paper.

10 years, 11 months

First release of zita-njbridge

by Fons Adriaensen

Zita-njbridge-0.1.0 is now available. Zita-j2n and zita-n2j are command line Jack clients to transmit full quality multichannel audio over a local IP network, with adaptive resampling by the receiver(s). Main features: * One-to-one (UDP) or one-to-many (multicast). * Sender and receiver(s) can each have their own sample rate and period size. No word clock sync is assumed. * Up to 64 channels, 16 or 24 bit or float samples. * Receiver(s) can select any combination of channels. * Low latency, optional additional buffering. * High quality jitter-free resampling. * Graceful handling of xruns, skipped cycles, lost packets and freewheeling. * IP6 fully supported. * Requires zita-resampler, no other non-standard dependencies. Note that zita-njbridge is meant for use on a *local* network providing more or less reliable delivery with low to moderate delay. It may work or not on the wider internet if receiver(s) are configured for additional buffering, and if you are lucky. Performance on wire- less networks is just a matter of chance. You will need a fairly recent Jack version, as the code uses jack_get_cycle_times() and no fallback for that is provided. Download from <http://kokkinizita.linuxaudio.org/linuxaudio/downloads/index.html> See man zita-njbridge for more info. -- FA A world of exhaustive, reliable metadata would be a It's also a pipe-dream, founded on self-delusion, nerd hubris and hysterically inflated market opportunities. (Cory Doctorow)

10 years, 11 months

computer keyboard control surface update

by Len Ovens

Please excuse my "youthful" enthusiasm... I am having some success with my usb computer keyboard as a midi control surface. All things are assignable to any key. the key events press, release, and repeat can be set separately (or ignored) Key presses can control: - Jack transport: roll stop zero 1 or ten sec forward or back (will make this settable) I have press do one second and repeat do 10 - midi messages these are all in hex and can include: channel messages like key, ctl, pgm, etc sysex up to 20 char in total I am not sure what the limit is for jack but any of the control surfaces I have studied seem to send less. The reality is that there are lots of control surfaces out there and sw has to handle what they send. I do have a question though about ardour control by midi. The Mackie IF says it sends control messages that are in the form num of ticks up or down. This means I should be able to have a key send ticks up and another ticks down, but this doesn't seem to work. Also, It seems the master rec-enable is not toggle-able. Odd. I have tried both making a map file and using the learn function. Is there more documentation for this somewhere? It would not be impossible to toggle things from inside the controler or take ticks up and down and convert to 127 or 1024 steps. This is not just for ardour but I am wanting to know what is standard. -- Len Ovens www.ovenwerks.net

10 years, 11 months

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Linux-audio-dev