Linux-audio-dev

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7520 discussions

Transport issue for Qtractor - has impact to the jitter issue

by Ralf Mardorf

Transport issue for Qtractor - has impact to the jitter issue So the advice to use amidiplay is something I'll follow soon. Hi all :), hi Robin :), hi Devin :) Robin, for 64 Studio 3.3 alpha the group has got read and write access to /dev/hpet too. Btw '[...] | sudo tee [...]' for 3.3 alpha isn't good, regarding to the enabled root account. Anyway, for this recording test I kept the value 64 for hpet/max-user-freq, but I'll test higher values soon. Devin and some others want to know if the drum module is played before FluidSynth DSSI is played. JACK2 doesn't start with -p4096, so I started JACK2 with -Rch -dalsa -dhw:0 -r44100 -p2048 -n2 to increase the unwanted effect, to get a clear result. Without recording it's clear audible that the external drum module always is played before FluidSynth DSSI is played, plausible regarding to the audio latency (stupid idea to use such high latency ;), so there's the need to do an audio test with lower latency, to see if jitter might change what instrument is played first. Instead of a rhythm I did record 4 to the floor at 120BPM to 'see' the jitter. I did record FluidSynth DSSI by the sound card too. Left channel the drum module, right channel FluidSynth DSSI and regarding to Qtractor's graphic of the wavefrorms, there is jitter for both! Ok, next recording with -Rch -dalsa -dhw:0 -r96000 -p512 -n2. Without recording it's already audible that the drum module is played first all the time ... and it's visible too. Again there's jitter for both. The audio recording of the drum module always is before the MIDI event. The recording of FluidSynth DSSI sometimes is before and sometimes after the MIDI event. There's no offset for the audio track. I kept -Rch -dalsa -dhw:0 -r96000 -p512 -n2 and recorded FluidSynth DSSI alone, internal Linux, without using the sound card. The audio recordings are before the MIDI events and there's jitter. I never noticed jitter internal Linux before. I need to repeat the test ASAP, but by using 64 Studio 3.0 beta and perhaps an older version of Qtractor. Playing FluidSynth DSSI by MIDI and the recording made internal Linux in unison, there isn't audible jitter. But after starting playing sometimes MIDI and the audio recording are perfectly synced and sometimes there's delay, real delay between the recording and MIDI, not only an early reflection like effect (but without audible jitter, the jitter only is visible by the waveforms). $ qtractor -v Qt: 4.5.2 Qtractor: 0.4.6 More maybe tomorrow. Cheers! Ralf

15 years, 5 months

controlling access to the sound card

by Jason Butler

I have three applications that want to use the sound card, two audio stream players, and a voip phone. I want to set up linux so that if a call comes in on the phone the OS will disconnect the audio players, give exclusive access to the voip phone, and then when the phone is done reconnect the audio players to the sound card. How can this be done?

15 years, 5 months

Sever issue?

by Ralf Mardorf

I guess nearly ever mail sent to LAD returned with an issue regarding to unable to deliver the message in the time limit specified to thaytan at noraisin dot net, while no mail was send to somebody who obviously has something seriously to do with GStreamer. Perhaps this is unimportant, but because I don't know, I guess it's better to inform about this 'issue' or 'non-issue' - Ralf

15 years, 5 months

Re: [LAD] [64studio-users] [64studio-devel] Correlation of alsa -p value and hw MIDI jitter

by Ralf Mardorf

No firewire here. I once had a MOTU, but I guess that there isn't a driver for Linux and the guy who lend me the MOTU + Mac was Dirk Brauner who isn't a friend anymore. I guess the MOTO was audio only. The people who are still my friends don't have much different equipment, but I've got. Always Envy24 based PCI, one friend has just more IOs for his Envy24 based PCI card. > Make sure that the MIDI device is being triggered before the soft > synth before you post to LAD. If it ends up being the case, then go > ahead and post it on LAD. You're right I was stupid to spread to much speculations. And yes, regarding to your knowledge you should join LAD. - Ralf

15 years, 5 months

Re: [LAD] [64studio-devel] [64studio-users] Correlation of alsa -p value and hw MIDI jitter

by Ralf Mardorf

On Wed, 2010-07-14 at 14:12 -0700, Devin Anderson wrote: > On Wed, Jul 14, 2010 at 12:43 PM, Ralf Mardorf > <ralf.mardorf(a)alice-dsl.net> wrote: > > On Wed, 2010-07-14 at 12:30 -0700, Devin Anderson wrote: > >> On Wed, Jul 14, 2010 at 10:29 AM, Ralf Mardorf > >> <ralf.mardorf(a)alice-dsl.net> wrote: > >> > >> > Hi :) > >> > > >> > delayed by a thunder-storm I could do another test. > >> > --snip-- > >> > >> So, what you're saying is that your MIDI device and software synth > >> sync up less and less as you raise the period size. > > > > Yes :). > > > >> I had presupposed > >> before that your MIDI device was triggering *after* your software > >> synth, but it occurs to me that it might be the other way around. Do > >> you hear the audio from your software synth first, or from your MIDI > >> device? > > > > I can't say it today, now I do some office work. I had the impression > > that it might vary. Sometimes the virtual drum sampler and sometimes the > > standalone drum sampler was played earlier, I need to check this ASAP. > > For older tests with my USB MIDI device it was exactly that way, that > > jitter had positive and negative delay. At least the recorded waveforms > > of external MIDI equipment (when I used USB MIDI, now I'm using PCI > > MIDI), were recorded by Qtractor, before theoretically the MIDI event > > was send ;). Note! Qtractor had no latency compensation, all recorded > > audio of external MIDI instruments should have (positive) delay, but > > negative delay. > > If it ends up being the case that your MIDI device is being triggered > before your software synth, then I'm guessing that the issue here is > not MIDI jitter. I'm guessing the issue is that the latency that's > imposed by JACK on incoming and outgoing audio is not imposed on > incoming and outgoing ALSA MIDI. So, while the audio coming out of > the software synth is delayed by a certain amount of frames imposed by > JACK, the audio coming out of your MIDI device is only delayed by the > latency of the ALSA drivers, the latency of the MIDI ports, the > latency of your MIDI device. > > This would certainly explain why the problem gets worse as you raise > the period size, and could explain why you had positive and negative > delay in your older USB MIDI tests, as the reported MIDI jitter in > your tests was *far* worse in your older tests than it is now. > > At the moment, I happen to be doing some work in JACK 2 that could > potentially solve this issue by enabling MIDI to sync more closely > with audio, so I'm very curious to know if my suspicions are correct. > Please keep me updated. :) Should I build JACK dummy packages for 64 Studio and daily get JACK2 from svn co http://subversion.jackaudio.org/jack/jack2/trunk/jackmp ? I wonder if this should be cross-posted to LAD? On LAD and the 64 Studio list are people with much knowledge and your reply might hit the nail on the head. - Ralf

15 years, 5 months

Re: [LAD] ALSA MIDI latency test results are far away from reality

by Robin Gareus

On 07/14/2010 06:31 PM, Nedko Arnaudov wrote: > Robin Gareus <robin-+VlDMftONaMdnm+yROfE0A(a)public.gmane.org> writes: > >> I was hinting that the audible midi-jitter could be a result of >> midi-messages getting 'quantizied' to jack-periods. >> >> A JACK-MIDI app which does not honor 'jack_midi_event_t->time' but >> simply processes all queued midi-events on each jack_process_callback() >> will result in the symptoms you describe (snare & kick on the same >> beat). One example of such an app is "a2j". > > What version? release-4 - the latest on svn://svn.gna.org/svn/a2jmidid > I can clearly see code that handles this in the current > version. It is in jack.c, a2j_alsa_output_thread(), lines 385-411 I've just seen that there's git://repo.or.cz/a2jmidid.git and jumped from release-4 to release-6. ciao, robin -- Robin Gareus mail: robin(a)gareus.org site: http://gareus.org/ chat: xmpp:rgareus@ik.nu blog: http://rg42.org/ lab : http://citu.fr/ Public Key at http://pgp.mit.edu/ Fingerprint : 7107 840B 4DC9 C948 076D 6359 7955 24F1 4F95 2B42

15 years, 5 months

Correlation of alsa -p value and hw MIDI jitter

by Ralf Mardorf

Hi :) delayed by a thunder-storm I could do another test. 64 Studio 3.3 alpha (= Ubuntu Karmic) amd64 LXDE, poff dsl-provider, cpufreq-selector -g performance, chgrp audio /dev/hpet, sysctl -w dev.hpet.max-user-freq=64, modprobe snd-hrtimer Qtractor + HR timer playing FluidSynth DSSI drums and a standalone MIDI drum module in unison. $ jackd -Rch -dalsa -dhw:0 -r96000 -p16 -n2 FluidSynth DSSI and the hardware MIDI drum module are playing in unison. $ jackd -Rch -dalsa -dhw:0 -r96000 -p512 -n2 Borderline, not out of timing, but not fine and already critical. $ jackd -Rch -dalsa -dhw:0 -r96000 -p256 -n2 Borderline, not out of timing, but not fine. $ jackd -Rch -dalsa -dhw:0 -r96000 -p128 -n2 Borderline, not out of timing, but not fine. $ jackd -Rch -dalsa -dhw:0 -r96000 -p64 -n2 Borderline, not out of timing, but not fine. $ jackd -Rch -dalsa -dhw:0 -r96000 -p32 -n2 It here might become usable. $ jackd -Rch -dalsa -dhw:0 -r96000 -p16 -n2 Yes, for this test the problem at -p32 and -p16 is, that because of phasing the kick become randomly very loud. It seems not to depend on the sounds, but jitter, anyway I can't say this for sure, some sounds can't be played in unison, even if there won't be jitter. Values >= -p64 result in ... I need to hear it again ... $ jackd -Rch -dalsa -dhw:0 -r96000 -p64 -n2 ... 'in unison' becomes a little bit of an early reflection like effect, but a very, very short delayed early reflection, still more a fluctuating phasing. $ jackd -Rch -dalsa -dhw:0 -r96000 -p1024 -n2 Completely out of sync, bad timing. Unusable. I guess even with -p16 one should record all drums and the bass at the same time, but recording every instrument one after another. This could be possible even for -p512, but MIDI is completely out of timing at -p1024, note, at 96KHz. Short attacked percussive sounds shouldn't be played in unison. For some usage PCI MIDI seems to be okay on my machine, but it's not comparable to an Atari ST and SMPTE sync to a 4-track cassette recorder or even to a C64 and click sync to a 4-track cassette recorder. PCI MIDI still has to much jitter for a straight timing, that enables to record one instrument after the other in perfect sync. I guess as long as I could keep -p256 and I won't be able to do a lot without increasing this value, hw MIDI could be usable for very simple music, when the whole MIDI backing is recorded at the same time, but one after the other instrument. - Ralf

15 years, 5 months

[ANN] Drumstick 0.4.1 released

by Pedro Lopez-Cabanillas

Drumstick is a C++ wrapper around the ALSA library sequencer interface using Qt4 objects, idioms and style. ALSA sequencer provides software support for MIDI technology on Linux. Complementary classes for SMF and WRK file processing are also included. This library is used in KMetronome, KMidimon and KMid2, and was formerly known as "aseqmm". Changes: * Removed the precompiled headers build option * Fixed a bug that affected users running dumstick-based applications with realtime priority enabled. There is a related problem in glib-2.22 that has not yet been fixed (https://bugzilla.gnome.org/show_bug.cgi?id=599079). This issue prevented to execute FluidSynth from inside KMid at startup in those affected systems. Copyright (C) 2009-2010, Pedro Lopez-Cabanillas License: GPL v2 or later Project web site http://sourceforge.net/projects/drumstick Online documentation http://drumstick.sourceforge.net/docs/ Downloads http://sourceforge.net/projects/drumstick/files/0.4.1/

15 years, 5 months

meta issue tracker idea

by Philipp

Hi, this is all about making Linux Audio more useful. The idea came about because on the one hand there are parts of Linux audio that really need some coders attention and on the other hand there are coders who don't know where to start. I realize that there never are more than enough coders, so this is mainly about bringing attention to the parts that need it the most. To a degree it's what bug/feature trackers are there for, but those are usually per application, and while there are category and priority systems in place those are rarely used. So what this is also about is bridging a gap between users, developers and between applications. It would be quite simple really. An easy to find, central place, possibly a wiki or a tracker. Anyone, a user most likely, describes his workflow and what the showstopper is. This could be applications not syncing properly, or an essential but missing feature. The idea is to tackle mainly infrastructure and cross application problems, with the goal to make a workflow actually work. The user should have to specify all relevant information available, such as version information, links, probably some kind of priority or urgency indication and how hard he believes it would be. He could also put up a reward of sorts, not necessarily monetary. Any developer could pick up the task and work on it, possibly leaving a notice. The possible benefits I see are: a) A kind of overview of what's needed the most, one place where you can see what's actually important to users. b) A way to identify and fix problems between applications - something I believe is very important for a system that encourages the use of multiple applications at once. I believe there are numerous synchronisation/transport issues for example which are never really tackled, despite this being a very important part of the infrastructure. c) Emphasis on actual workflow and usability. d) It would work for any program, even those without tracker and those that aren't high profile and aren't usually in the center of attention. Could this work? What do you think? -- Regards, Philipp -- "Wir stehen selbst enttäuscht und sehn betroffen / Den Vorhang zu und alle Fragen offen." Bertolt Brecht, Der gute Mensch von Sezuan

15 years, 5 months

Is anyone using monobristol 0.60.1?

by Mike Cookson

I am using KX Studio. Latest Mono version is 2.4.4 from SVN, though the latest version is 2.6.4. Latest monobristol version from repository, 0.40.5, works, but bristol version there is 0.60.1. I compiled latest monobristol (0.60.1) with defaults and installed to /usr/local. It worked when launched from terminal, but failed to start from fbrun and gmrun and cairo-dock. KDE menu and kwin run dialog started old 0.40.5 version, though its command string is simply "monobristol". When I reinstalled it to /usr, it failed to start even from terminal. When it fails, it gives this error: Unhandled Exception: System.NullReferenceException: Object reference not set to an instance of an object at MainWindow..ctor () [0x00000] at monoBristol.MainClass.Main (System.String[] args) [0x00000] I searched in web and found it like a mono bug, but I am unsure. I need to be checked by developers before reporting.

15 years, 5 months

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Linux-audio-dev