Re: [linux-audio-dev] Apple's distributed audio processing technology

2004-09-30 Thread Martijn Sipkema
> > > No details about the protocols used. Gigabit ethernet is recommended for > > > "the best performance". > > > > > Mmm ... It says: > > > > The protocol is independent of the network hardware, thanks > > to the use of the standard TCP. > > > > > > So, tcp/ip? > > More likely is mLAN ove

Re: [linux-audio-dev] a question re: the MIDI spec

2004-09-14 Thread Martijn Sipkema
> > > > It's not unusable, but IIRC it can get to several ms of jitter. > > > > > > Why is that? The USB iso clock is every ms IIRC, so naively you > > > would expect the maximum jitter to be just under 1ms (if the bus was > > > saturated by audio transfers), and less in proportion to the degree of

Re: [linux-audio-dev] a question re: the MIDI spec

2004-09-11 Thread Martijn Sipkema
> > [...] > > > > > > The problem here is that class compliant devices suffer bad timing > > > > > > because they use bulk transfers for MIDI data. The standard for > > > > > > MIDI over FireWire is much better. > > [...] > > > > > Is the timing really that bad? I don't even think a firewire 8x8 >

Re: [linux-audio-dev] a question re: the MIDI spec

2004-09-11 Thread Martijn Sipkema
[...] > > MIDI streams need a reliable transport with guaranteed bandwidth. If > > USB can't provide this, then it is not really suitable for MIDI, but I'm not > > saying it is unusable, just that it may perform worse then traditional > > serial multiport MIDI interfaces. > > USB can provide this

Re: [linux-audio-dev] a question re: the MIDI spec

2004-09-10 Thread Martijn Sipkema
> > The problem here is that class compliant devices suffer bad timing > > because they use bulk transfers for MIDI data. The standard for > > MIDI over FireWire is much better. > > I don't agree on the subject that USB bulk transfers cause bad MIDI timing. > Of course, you can't use the same US

Re: [linux-audio-dev] a question re: the MIDI spec

2004-09-10 Thread Martijn Sipkema
[...] > > > > The problem here is that class compliant devices suffer bad timing > > > > because they use bulk transfers for MIDI data. The standard for > > > > MIDI over FireWire is much better. [...] > > > Is the timing really that bad? I don't even think a firewire 8x8 > > > rackmount MIDI inte

Re: [linux-audio-dev] a question re: the MIDI spec

2004-09-10 Thread Martijn Sipkema
> On Fri, 2004-09-10 at 07:49, Martijn Sipkema wrote: > > >> [...] the USB specification. And it even appears like some vendors > > >> are (finally!) starting to follow suit: > > >> > > >>http://midiman.com/products/en_us/KeystationPro88-m

Re: [linux-audio-dev] a question re: the MIDI spec

2004-09-10 Thread Martijn Sipkema
>> [...] the USB specification. And it even appears like some vendors >> are (finally!) starting to follow suit: >> >>http://midiman.com/products/en_us/KeystationPro88-main.html >> >>- "USB class compliant-no drivers required for >> Windows XP or Mac OS X" > > M-Audio started following

Re: [linux-audio-dev] Audio synchronization, MIDI API

2004-08-14 Thread Martijn Sipkema
From: "Steve Harris" <[EMAIL PROTECTED]> > On Sat, Aug 14, 2004 at 10:07:06PM +0200, Benno Senoner wrote: > > >UDP also has unbounded transit time. In practice its OK if you dont want > > >low latencies (just use RTP), but for low latency you really need one of > > >the non-IP ethernet protocols th

Re: [linux-audio-dev] Re: desktop and multimedia as an afterthought?

2004-07-14 Thread Martijn Sipkema
From: "Bill Huey (hui)" <[EMAIL PROTECTED]> > On Tue, Jul 13, 2004 at 11:44:59PM +0100, Martijn Sipkema wrote: > [...] > > The worst case latency is the one that counts and that is the contended case. If > > you could guarantee no contention then the worst case

Re: [linux-audio-dev] Re: desktop and multimedia as an afterthought?

2004-07-14 Thread Martijn Sipkema
From: "Bill Huey (hui)" <[EMAIL PROTECTED]> > On Tue, Jul 13, 2004 at 01:09:28PM +0100, Martijn Sipkema wrote: > > [...] > > > Please double-check that there are no priority inversion problems and that > > > the application is correctly setting the sche

Re: [linux-audio-dev] Re: desktop and multimedia as an afterthought?

2004-07-13 Thread Martijn Sipkema
From: "Paul Davis" <[EMAIL PROTECTED]> > >Hmm, I've just recently learned about the Priority Ceiling Protocol, > >an extension to Priority Inversion Protocol, which explicitly prevents > >deadlocks. And I've learned about both in a RTOS course, so I'm a little > >surprised by your statement about t

Re: [linux-audio-dev] Re: desktop and multimedia as an afterthought?

2004-07-13 Thread Martijn Sipkema
From: "Christian Henz" <[EMAIL PROTECTED]> > On Tue, Jul 13, 2004 at 10:55:48AM -0400, Paul Davis wrote: > > >Thus, the fact that Linux does not support protocols to prevent priority > > >inversion (please correct me if I am wrong) kind of suggests that supporting > > >realtime applications is not

Re: [linux-audio-dev] Re: desktop and multimedia as an afterthought?

2004-07-13 Thread Martijn Sipkema
From: "Paul Davis" <[EMAIL PROTECTED]> > >Thus, the fact that Linux does not support protocols to prevent priority > >inversion (please correct me if I am wrong) kind of suggests that supporting > >realtime applications is not considered very important. > > we went through this (you and i in parti

Re: [linux-audio-dev] Re: desktop and multimedia as an afterthought?

2004-07-13 Thread Martijn Sipkema
Benno Senoner wrote: > Martijn Sipkema wrote: > >It is often heard in the Linux audio community that mutexes are not realtime > >safe and a lock-free ringbuffer should be used instead. Using such a lock-free > >ringbuffer requires non-standard atomic integer operations and

Re: [linux-audio-dev] Re: desktop and multimedia as an afterthought?

2004-07-13 Thread Martijn Sipkema
[...] > Please double-check that there are no priority inversion problems and that > the application is correctly setting the scheduling policy and that it is > mlocking everything appropriately. I don't think it is currently possible to have cooperating threads with different priorities without p

Re: [linux-audio-dev] Buffer size settings - Mac/Windows

2004-06-13 Thread Martijn Sipkema
[...] > interestingly, the design of ASIO only allows 2 interrupts per > hardware buffer. ALSA is much more flexible in handling this kind of > thing. A huge mistake of ASIO IMHO. On the Audiowerk8 for example, running 3 interrupts per buffer allows using the input DMA interrupt only; this interr

Re: [linux-audio-dev] [OT] marketing hype

2004-06-11 Thread Martijn Sipkema
[...] > > Sorry Fons, but define acceptable! Please! > > I will define as non-acceptable the implication: > >Paul uses a text based mail client >=> >this explains why his GUI designs are cluttered. > > It would be acceptable and in this context even funny with a :-), > but I didn't s

Re: [linux-audio-dev] Two or more monitors)Re:Project:modularsynth editor

2004-01-20 Thread Martijn Sipkema
> [...] > > > Right, but resolution is just a matter of RAMDAC parameters. All > > > I want is a 3856x1536 framebuffer with one RAMDAC displaying a > > > 2048x1536 window and the other displaying a 1808x1356 window. I > > > don't care about one tiny MB of VRAM being invisible. > > > > True, this sh

Re: [linux-audio-dev] Two or more monitors) Re:Project:modularsynth editor

2004-01-20 Thread Martijn Sipkema
[...] > > > There is another mode, where a single buffer forms a big desktop, > > > of which each RAMDAC displays a part. Seems like stupid driver > > > limitations restrict this mode to using the same resolution for > > > both heads, but I'm not sure. > > > > It is to be expected that a single ren

Re: [linux-audio-dev] Two or more monitors) Re: Project: modularsynth editor

2004-01-19 Thread Martijn Sipkema
[...] > I just remembered; the Matrox G100/200/400 drivers and/or hardware has > problems with multiple OpenGL contexts. Matrox have known about it > for ages, but seem to ignore the problem. This is part of the reason > why I gave up on my G400. Most likely a driver problem (or elsewhere in the s

Re: [linux-audio-dev] Two or more monitors) Re: Project:modularsynth editor

2004-01-19 Thread Martijn Sipkema
[...] > > IIRC Matrox cards have a way of making a single framebuffer (with > > xinerama hints) that appears on two monitors. That way you should > > get 3d accel on both displays. > > ATI has something similar, but their drivers don't seem to work with > Xinerama the normal way. It (sort of) wor

Re: [linux-audio-dev] Two or more monitors) Re: Project:modularsynth editor

2004-01-19 Thread Martijn Sipkema
> > [...] > > > Xinerama _does_ support open GL, at least with my matrox card, I can have > > > openGL on one monitor of the two. That is a limitation of the card > > > hardware, AFAIK, not of X. > > > > I doubt this is a hardware limitation. The hardware just renders to AGP or > > local memory. I

Re: [linux-audio-dev] Two or more monitors) Re: Project: modularsynth editor

2004-01-19 Thread Martijn Sipkema
[...] > Xinerama _does_ support open GL, at least with my matrox card, I can have > openGL on one monitor of the two. That is a limitation of the card > hardware, AFAIK, not of X. I doubt this is a hardware limitation. The hardware just renders to AGP or local memory. I may be wrong though... --

Re: [linux-audio-dev] Re: gQ for Linux

2003-08-14 Thread Martijn Sipkema
[...] > What is 'ALport' and 'ALconfig', and where are they > defined? Those are part of the SGI audio library and I woudn't expect them to be available under Linux. --ms

Re: [linux-audio-dev] Direct Stream Digital / Pulse Density Modulationmusing/questions

2003-07-28 Thread Martijn Sipkema
[...] > Conventional PCM techniques are unable to reproduce high frequencies > correctly. And the explanation is very simple. Actually a correct explanation isn't that simple. Yours is much _too_ simple. Theoretically a 20 kHz bandlimited signal can be represented _exactly_ as a 40 kHz PCM stream.

Re: [linux-audio-dev] kernel 2.6

2003-07-25 Thread Martijn Sipkema
> On Thursday 24 July 2003 13:46, Michael Ost wrote: > > Is there SCHED_FIFO style priority available in the new kernel, with its > > new threading model? Realtime audio processing doesn't share the CPU > > very well. The ear can pick out even the slightest glitches or delays. > > So for Linux to b

Re: [linux-audio-dev] new realtime scheduling policy

2003-03-18 Thread Martijn Sipkema
> so i've tried to make a new scheduling policy for linux. i've > called it SCHED_USERFIFO. the intent is basically to allow a process > ask for x amount of processor time out of every y jiffies. (the user > part is in the hope that the administrator can set rlimits on the > amount of perce

Re: [linux-audio-dev] midi 'resolution'

2003-03-17 Thread Martijn Sipkema
> In a system/application, that recieves external midi data of any kind, > is there anything one can assume about _when_ some midi data is recieved? > > i mean, with audio data, you have the buffer size of the dac/adc, which > (together with sampling rate) enforces some kind of "global clock" >

Re: [linux-audio-dev] Linux Alsa Audio over 1394 - a Thesis

2003-02-26 Thread Martijn Sipkema
> > Because I think ALSA does too much in the kernel (and it is not > > well documented eiter). > > Wait a minute, why do you say that? Because: - I think ALSA is not that well documented. - I'd rather see a combination of a device specific kernel driver and a user-space driver than a common kern

Re: [linux-audio-dev] Linux Alsa Audio over 1394 - a Thesis

2003-02-26 Thread Martijn Sipkema
[...] > >I don't think an application should ask for a certain number of frames > >to wakeup. The driver should dictate when to wake up. This is the way > >my Audiowerk8 JACK driver works and it would get a lot more > >complicated if I had to add support for user-space wake up at > >arbitrary inter

Re: [linux-audio-dev] Linux Alsa Audio over 1394 - a Thesis

2003-02-26 Thread Martijn Sipkema
> > Well, I'll shut up about it. I still think it is a mistake. I haven't heard > > any > > convincing (to me) arguments why an application should not handle variable > > sized callbacks. > > Because it makes certain types of processing viable, which they are not > really in variable block systems

Re: [linux-audio-dev] Linux Alsa Audio over 1394 - a Thesis

2003-02-26 Thread Martijn Sipkema
> >any > >convincing (to me) arguments why an application should not handle variable > >sized callbacks. VST process() is variable size I think as are EASI xfer > >callbacks, but clearly JACK needs constant callbacks and there is nothing > >I can do about that... > > as i understand it, VST is only

Re: [linux-audio-dev] Linux Alsa Audio over 1394 - a Thesis

2003-02-26 Thread Martijn Sipkema
> > > According to the mLAN spec you need a buffer of around ~250us (depending > > > on format) to collate the packets. > > > > Still there is no guarantee that 10 packets always have exactly the same > > number of samples. You say the mLAN spec says you need a buffer of > > around ~250us. No

Re: [linux-audio-dev] Linux Alsa Audio over 1394 - a Thesis

2003-02-26 Thread Martijn Sipkema
> On Wed, Feb 26, 2003 at 12:38:38 +0100, Martijn Sipkema wrote: > > Still there is no guarantee that 10 packets always have exactly the same > > number of samples. You say the mLAN spec says you need a buffer of > > around ~250us. Note that is doesn't say a buffer of a

Re: [linux-audio-dev] Linux Alsa Audio over 1394 - a Thesis

2003-02-26 Thread Martijn Sipkema
[...] > The bottom level packets are sent at fixed time intervals (obviously, > corresponding to the frame clock of the bus), but these packets are tiny > and you get millions of them per second. A useful packet of audio data > will be made up of a bunch of these. > > According to the mLAN spec yo

Re: [linux-audio-dev] Linux Alsa Audio over 1394 - a Thesis

2003-02-26 Thread Martijn Sipkema
> > I'm not sure, but it seems the audio transport over FireWire does not > > deliver a constant number of frames per packet. Does this mean that > > JACK cannot support FireWire audio without extra buffering? > > ISO packets are a fixed size, so there will be a constant number of > frames per pac

Re: [linux-audio-dev] Linux Alsa Audio over 1394 - a Thesis

2003-02-25 Thread Martijn Sipkema
> Some folks here might find this of interest. I do... > > http://www.cs.ru.ac.za/research/g99s2711/thesis/thesis-final.pdf I'm not sure, but it seems the audio transport over FireWire does not deliver a constant number of frames per packet. Does this mean that JACK cannot support FireWire audio

Re: [linux-audio-dev] BruteFIR + jack = crackling noise?

2003-02-25 Thread Martijn Sipkema
> >IMHO the hardware should dictate the blocksize. For most audio > >interfaces this will be constant. For some it is not. > > the claim is that designs in which it is not constant are at least > less than optimal and at worst, just stupid. Well, I disagree. I don't think it is a stupid design.

Re: [linux-audio-dev] BruteFIR + jack = crackling noise?

2003-02-25 Thread Martijn Sipkema
[...] > I'm a newbie to LAD, but I have some years of experience of developing > and using a system similar to JACK for routing blocks of samples to > DSP modules of a digital satellite control receiver and transmitter > system running on Solaris (we are talking about some megasamples per > second

Re: [linux-audio-dev] BruteFIR + jack = crackling noise?

2003-02-24 Thread Martijn Sipkema
[...] > Instead I would suggest a built in poll mode in JACK for audio hardware > with strange period sizes. Although not the most beautiful solution, it > will work reliably and will only be needed for the type of hardware > that cannot provide interrupt rates which is a power of two. I'm not a J

Re: [linux-audio-dev] BruteFIR + jack = crackling noise?

2003-02-24 Thread Martijn Sipkema
> > [...] > > > > Perhaps you would reconsider having JACK use constant (frames) > > > > callbacks? > > > > > > I think a better solution might be to buffer up enough samples so that > > > jackd can provide a constant number of frames. > > > > I don't think that is a better solution. JACK should be

Re: [linux-audio-dev] BruteFIR + jack = crackling noise?

2003-02-24 Thread Martijn Sipkema
[...] > > Perhaps you would reconsider having JACK use constant (frames) > > callbacks? > > I think a better solution might be to buffer up enough samples so that > jackd can provide a constant number of frames. I don't think that is a better solution. JACK should be close to the hardware and del

Re: [linux-audio-dev] BruteFIR + jack = crackling noise?

2003-02-24 Thread Martijn Sipkema
[...] > many USB audio interfaces work in a fundamentally different way than > other audio interfaces. rather than sending an "interrupt" to the host > after processing 2^N frames, they send an interrupt every N > msecs. And JACK doesn't support this because it needs a constant size (frames) peri

Re: [linux-audio-dev] crusoe ll problems

2003-02-21 Thread Martijn Sipkema
> I'm trying to run a low latency kernel and audio applications on a > crusoe processor laptop. > > Yes, I'm crazy. You might want to take a look at the following: http://www.mindcontrol.org/~hplus/aes-2001 In slide 5/6 three different processors are compared and the 400 MHz Transmeta Crusoe is

Re: [linux-audio-dev] MIDI Clock and ALSA seq

2003-02-17 Thread Martijn Sipkema
[...] > Isn't the pulse of MIDI clock defined by the BPM, that's how all > instruments synced to MIDI clock work... 24 MIDI clock messages are to be sent per quarter note. --ms

Re: [linux-audio-dev] (OT) C++ flame war

2003-02-06 Thread Martijn Sipkema
[...] > If you don't know *every* detail of > a struct, you can't create an instance of one, because you don't know > it's *size*. And the offset of its members. [...] > So, the basic problem is that it's not the constructor that allocates > memory for the instance; it's the code generated by the

Re: [linux-audio-dev] (OT) C++ flame war

2003-02-06 Thread Martijn Sipkema
[...] > >No, it requires a pure virtual class per distinct interface (abstract > >class). And I don't see why this would not scale. > > you should try writing ardour :) It might be me who won't scale :) I know writing large applications is not easy. > >A friend is just like a member function, i.e

Re: [linux-audio-dev] (OT) C++ flame war

2003-02-06 Thread Martijn Sipkema
[...] > i love C++. i think its one of the best things ever. but i happen to > agree with Erik. the solution proposed by martijn doesn't scale well, > and doesn't really address the issue in a comprehensive way. it > requires one pure virtual class per distinct set of private members, > for a start

Re: [linux-audio-dev] (OT) C++ flame war

2003-02-05 Thread Martijn Sipkema
> > You are not forced to define the private data members and functions at the > > same time as the public ones in C++. The way to handle this is to put the public > > interface in a pure virtual class: > > In my opinion (please note that this IS an opinion) the method you propose > is at least as

Re: [linux-audio-dev] (OT) C++ flame war

2003-02-05 Thread Martijn Sipkema
[...] > for an on-topic rant, see Erik de Castro Lopo's interview on mstation.org: > > http://mstation.org/erikdecl.php > > where he discusses the OO design of libsndfile and libsamplerate > (surely two of the most rock-solid audio libraries ever!) >From this article: "I also think that there i

Re: [linux-audio-dev] newest audio server for Linux (yep, yet ano ther)

2003-02-05 Thread Martijn Sipkema
[...] > :-) I have exactly the same problem with templates, it pretends to be > dynamic while it's just statically generated (=similar to preprocessor, > which I guess is your point) I think the C++ STL is great and a perfect example of the power of templates. Much better than GLib, and it's sta

Re: [admin] hold it... Re: [linux-audio-dev] New software synthesizer for Linux (free under GPL v. 2)

2002-09-26 Thread Martijn Sipkema
[...] > hold it, guys. (i know, i sometimes can't resist, too.) I was just able to resist this time... > please stop this thread and respect anybody's choice of "license" or > whatever conditions they might offer their software under. if you don't > like it, don't use it. I think the question a

[linux-audio-dev] Low level Audiowerk8 driver for Linux (2.4)

2002-09-03 Thread Martijn Sipkema
Hi, I've written a low level, i.e. it is not ALSA/OSS but a device specific interface, driver for the Emagic Audiowerk8 audio card. I still need to implement I2C (for setting the sample rate) and switching the input (analog/digital) and the buffer size is currently fixed (set at compile time) at

Re: [Alsa-devel] Re: [linux-audio-dev] midi events in jack callback / ALSA Sequencer

2002-08-22 Thread Martijn Sipkema
> Why is it important to keep the API simple, shouldn't it be functional in first place and make the API usage simply? Who says a simple API can't be functional? > Anyway (IMHO), there should really be an API which combines audio and MIDI playback, recording and timing of events and makes it pos

Re: [Alsa-devel] Re: [linux-audio-dev] midi events in jack callback / ALSA Sequencer

2002-08-22 Thread Martijn Sipkema
> > I don't want to support tempo (MIDI clock) scheduling in my MIDI API. This > > could be better handled in the application itself. Also, when slaved to MIDI > > clock > > it is no longer possible to send messages ahead of time, and not supporting > > this > > in the API makes that clear to the

Re: [linux-audio-dev] midi events in jack callback / ALSA Sequencer

2002-08-20 Thread Martijn Sipkema
[...] > Within ALSA we have two priority queues, one for tick (bar,beat) scheduled > events, and one for clock (ns) scheduled events. As MIDI uses MIDI tick messages for time based sync and MIDI clock messages for tempo based sync I kind of feel the ALSA sequencer naming is a little confusing :)

Re: [linux-audio-dev] midi events in jack callback (was: Reborn)

2002-08-19 Thread Martijn Sipkema
> >MIDI through and any other 'immediate' type MIDI messages do > >not need to be scheduled, they can be written to the interface immediately. > > Yes, they could. It would however necessitate different input routes > for 'immediate' and 'queued' events to the MIDI output handler. The MIDI I/O AP

Re: [linux-audio-dev] midi events in jack callback (was: Reborn)

2002-08-19 Thread Martijn Sipkema
[...] > >User space MIDI scheduling should run at high rt priority. If scheduling > >MIDI events is not done at a higher priority than the audio processing > >then it will in general suffer jitter at the size of the audio interrupt > >period. > > Jitter amounting to the length of time the audio cy

Re: [linux-audio-dev] Re: [Alsa-devel] Forcing an absolute timestamp for every midi event.

2002-08-18 Thread Martijn Sipkema
[...] > Is there already a commonly available UST on linux? To my knowledge the only > thing that comes close is the (cpu specific) cycle counter. No, not yet. I think we should try to get hard- or firm-timers and POSIX CLOCK_MONOTONIC into the Linux kernel. --martijn

[linux-audio-dev] Re: [Alsa-devel] Forcing an absolute timestamp for every midi event.

2002-08-18 Thread Martijn Sipkema
> Hi! I wanted to ask, how about forcing > an absolute timestamp for _every_ midi event? > I think this would be great for softsynths, > so they dont need to work with root/schedfifo/lowlatency > to have a decent timing. Not allways you are willing > to process midi at the lowest latency possible.

Re: [linux-audio-dev] Locking Midi to Audio

2002-08-17 Thread Martijn Sipkema
[...] > i just want to note my happiness at reading a post from martijn with > which i agree 100% !! who says there is no such thing as progress ? :)) Indeed Paul, I'd agree you've made some real progress here :) --martijn

Re: [linux-audio-dev] Locking Midi to Audio

2002-08-17 Thread Martijn Sipkema
> This is an idea I had some time ago and simply have not had the time to > explore. > > Nowadays few people would want to do Midi without doing audio at the same > time. This potentially leads to a great simplification in the handling of > Midi. > > Why not lock the Midi processing to the audio p

Re: [linux-audio-dev] midi events in jack callback (was: Reborn)

2002-08-16 Thread Martijn Sipkema
> So we need something which handles the timing like the DirectMusic(tm) in > the Linux kernel. I would prefer not to have this in the kernel. If the kernel provides accurate scheduling and CLOCK_MONOTONIC then I think this can and should be done from user-space. A driver should be able to read C

Re: [linux-audio-dev] midi events in jack callback (was: Reborn)

2002-08-16 Thread Martijn Sipkema
> I find that for sending MIDI to an external device, "resolution = RTC > Hz" works very well. It is a problem that a realtime audio thread > 'suffocates' a RTC thread if low-latency is required, and only one > processor available. It's very hard to find a clean solution in this > case, but firm

Re: [linux-audio-dev] midi events in jack callback (was: Reborn)

2002-08-16 Thread Martijn Sipkema
> >Haven't written anything using MIDI and JACK (or LADSPA), but would it be poss > >ible to have a such system as with Cubase where the softsynths are plugins whi > >ch receive time-stamped MIDI events (time-stamp is an offset from the block be > >ginning in samples). Either this (use audio samp

Re: [linux-audio-dev] Jack and block-based algorithms (was: Reborn)

2002-08-14 Thread Martijn Sipkema
> How does the pull model work with block-based algorithms that cannot > provide any output until it has read a block on the input, and thus > inherently has a lower bound on delay? > > I'm considering a redesign of I/O handling in BruteFIR to add Jack > support (I/O is currently select()-based),

Re: [linux-audio-dev] App intercomunication issues, some views.

2002-07-25 Thread Martijn Sipkema
> >on every callback. If a node does internal buffering that should not affect > >the MSCs. > > right, because there isn\'t really an MSC anywhere. as you noted, the > global jack transport time isn\'t really equivalent. nothing in the > main JACK API says anything about doing anything except han

Re: [linux-audio-dev] App intercomunication issues, some views.

2002-07-24 Thread Martijn Sipkema
[...] > > consider:node B >/\\ > ALSA PCM -> node Anode D -> ALSA PCM >\\/ >node C > > what is the latency for output of data from node A ? it depends on > what happens at n

Re: [linux-audio-dev] App intercomunication issues, some views.

2002-07-24 Thread Martijn Sipkema
> >If I use an absolute sleep there is basically no difference. The drift > >will be the same, but instead of scheduling events from \'now\' I can > >spcify the exact time. So a callback would then be like: > > > >- get the UST and MSC for the first frame of the current buffer for input > > MSC

Re: [linux-audio-dev] App intercomunication issues, some views.

2002-07-24 Thread Martijn Sipkema
> nanosleep isn\'t based on time-of-day, which is what is subject to > adjustment. nanosleep uses the schedule_timeout, which is based on > jiffies, which i believe are monotonic. I\'m not sure how nanosleep() is supposed to handle clock adjustment but I agree it would probably not change its beh

Re: [linux-audio-dev] App intercomunication issues, some views.

2002-07-24 Thread Martijn Sipkema
> >[...] > >> UST can be used for timestamping, but thats sort of useless, since the > >> timestamps need to reflect audio time (see below). > > > >I\\\'d like to have both a frame count (MSC) and a corresponding system time > >(UST) for each buffer (the first frame). That way I can predict when (

Re: [linux-audio-dev] App intercomunication issues, some views.

2002-07-24 Thread Martijn Sipkema
[...] > if you find the link for the > ex-SGI video API developer\'s comment on the dmSDK, i think you may > also see some serious grounds for concern about using this API. i\'m > sorry i don\'t have it around right now. is it http://www.lurkertech.com/linuxvideoio.html ? this is about the older

Re: [linux-audio-dev] UST

2002-07-24 Thread Martijn Sipkema
> their stuff has never been widely (if at all) used for low latency > real time processing of audio. [...] > ...it doesn\'t get used this way > because (1) their hardware costs too much (2) their API for audio > doesn\'t encourage it in any way (3) their API for digital media in > general is conf

Re: [linux-audio-dev] App intercomunication issues, some views.

2002-07-24 Thread Martijn Sipkema
[...] > Its worth noting that SGI\'s \"DM\" API has never really taken > off, and there are lots of reasons why, some technical, some > political. Perhaps. See http://www.khronos.org/ for where SGI\'s dmSDK might still be going. I think this API might be good for video. So maybe it is not that go

Re: [linux-audio-dev] App intercomunication issues, some views.

2002-07-24 Thread Martijn Sipkema
[...] > UST can be used for timestamping, but thats sort of useless, since the > timestamps need to reflect audio time (see below). I\'d like to have both a frame count (MSC) and a corresponding system time (UST) for each buffer (the first frame). That way I can predict when (UST) a certain perfo

Re: [linux-audio-dev] App intercomunication issues, some views.

2002-07-23 Thread Martijn Sipkema
[...] > UST = Unadjusted System Time I believe this is a good introduction to UST/MSC: http://www.lurkertech.com/lg/time/intro.html --martijn Powered by ASHosting

Re: [linux-audio-dev] App intercomunication issues, some views.

2002-07-23 Thread Martijn Sipkema
[...] > UST = Unadjusted System Time > > I haven\'t seen any implementations of UST where you could specify a > different source of the clock tick than the system clock/cycle timer. Well, no. Is this needed. The UST should just be an accurate unadjusted clock that can be used for timestamping/sc

Re: [linux-audio-dev] App intercomunication issues, some views.

2002-07-23 Thread Martijn Sipkema
> >Does that mean that MIDI output can only be done from a callback? > > No, it would mean that MIDI is only actually delivered to a timing > layer during the callback. Just as with the ALSA sequencer and with > audio under JACK, the application can queue up MIDI at any time, but > its only deli

Re: [linux-audio-dev] App intercomunication issues, some views.

2002-07-23 Thread Martijn Sipkema
On 23.07.2002 at 15:35:58, Paul Davis <[EMAIL PROTECTED]> wrote: > >On Tue, Jul 23, 2002 at 07:48:45 -0400, Paul Davis wrote: > >> the question is, however, to what extent is it worth it. the reason > >> JACK exists is because there was nothing like it available for moving > >> audio data around.

Re: [linux-audio-dev] App metadata intercomunication protocol..

2002-07-23 Thread Martijn Sipkema
> Yep, think of 0-127 ranges for controller data :( > That is too coarse; MIDI provides 14bit controller resolution by having controller pairs. That should be enough for controller since most sliders/knobs on hardware have much less than that. Pitch bend is 14bit also, allthough there is a lot of

Re: [linux-audio-dev] LADPSA v1.1 SDK Provisional Release

2002-07-12 Thread Martijn Sipkema
> >Well, it\'s not _that_ important, but there are a few good reasons... > > > >1) The LADSPA API was not designed for ABI changes (most notably the > > interface version is not exported by plugins). This means that > > old plugins that you didn\'t remember to delete/recompile can > > caus

Re: [linux-audio-dev] priority inversion & inheritance

2002-07-11 Thread Martijn Sipkema
> Let\'s say we have threads A (SCHED_FIFO/50) and B (SCHED_FIFO/90). If both > threads are runnable, B will always be selected and it will run until > (quoting the man page) \"... either it is blocked by an I/O request, it is > preempted by a higher priority process, or it calls sched_yield\". >

Re: [linux-audio-dev] priority inversion & inheritance

2002-07-11 Thread Martijn Sipkema
> >> For instance if you have > >> a mixer element in the signal graph, it is just easier if all the inputs > >> deliver the same amount of data at every iteration. > > Hmm, why? I can see that it is a requirement that at every iteration there > > is the same data available at the input(s) as is

Re: [linux-audio-dev] priority inversion & inheritance

2002-07-11 Thread Martijn Sipkema
> >> The two threads must run with SCHED_FIFO as they both need to complete > >> their cycle before the next soundcard interrupt. > > And even if they both run SCHED_FIFO, they should then also run at the same > > priority. > > Not needed. The SCHED_FIFO protects against from other tasks taking t

Re: [linux-audio-dev] priority inversion & inheritance

2002-07-11 Thread Martijn Sipkema
> On Thu, Jul 11, 2002 at 04:31:18PM +0200, Martijn Sipkema wrote: > > When implementing a FIFO that is read by a low priority thread and written > > by a higher priority thread (SCHED_FIFO) that is not allow to block when > > writing the FIFO for a short, bounded time. Then

Re: [linux-audio-dev] priority inversion & inheritance

2002-07-11 Thread Martijn Sipkema
> I must have explained things quite poorly in the article you said you > read. Having a live scheduler allows you to _not_ understand all the > complex interactions between blocking operations in your system because > the liveness means that eventually whatever thread you are waiting for > will

Re: [linux-audio-dev] priority inversion & inheritance

2002-07-11 Thread Martijn Sipkema
> [constant nframes] > > But why is this needed? The only valid argument I heard for this is > > optimization of frequency domain algorithm latency. I suggested a > > capability interface for JACK as in EASI where it is possible to ask > > whether nframes is constant. The application must still ha

Re: [linux-audio-dev] priority inversion & inheritance

2002-07-11 Thread Martijn Sipkema
> One simple reason, whether a valid design or not, is that there\'s a lot of > code that handles audio in constant size blocks. Ok. I give up. It\'s clear that most find this more important that the issue with hardware. > For instance if you have > a mixer element in the signal graph, it is jus

Re: [linux-audio-dev] priority inversion & inheritance

2002-07-11 Thread Martijn Sipkema
so, to summarize: nframes != constant - (better) support for various (stupid) hardware. nframes == constant: 1- Easier porting of read/write applications. 2- Optimized latency of FFT; FFT done on period size. This would also require a power of 2 sized period. So not having nframes constant

Re: [linux-audio-dev] priority inversion & inheritance

2002-07-11 Thread Martijn Sipkema
> >Again, I agree with you. That\'s also why I am against a constant nframes, > >because there is hardware that really doesn\'t want nframes constant. > > such as? How should I know? :) I heard some yamaha soundcards generate interrupts at a constant rate not depending on the sample rate. Perhap

Re: [linux-audio-dev] priority inversion & inheritance

2002-07-11 Thread Martijn Sipkema
> There\'re two separate problems here. Constant nframes might be required > even if the application supports engine iteration from outside sources > (ie. all audio processing happens inside the process() callback). > Ecasound is one example of this. But why is this needed? The only valid argum

Re: [linux-audio-dev] priority inversion & inheritance

2002-07-11 Thread Martijn Sipkema
> >An examples situation for using priority inheritance > >might be porting a read/write audio i/o application to a > >callback based interface without too much effort. This can\\\'t in the > >general case be done without adding latency, if there is no blocking > >allowed in the callback funct

Re: [linux-audio-dev] priority inversion & inheritance

2002-07-11 Thread Martijn Sipkema
> Linux is not real-time, it has a scheduler that, generally, makes sure > eventually everyone gets to run. I think people often understimate > how useful a \\\"live\\\" scheduler is and how limited a real-time priority > scheduler is. I agree. That\'s why it is needed. And for realtime threads

Re: [linux-audio-dev] priority inversion & inheritance

2002-07-10 Thread Martijn Sipkema
> victor yodaiken wrote a nice article on why priority inheritance as a > way of handling priority inversion isn\\\'t a particularly attractive > solution. I read this article, but I am not convinced. The only argument against using priority inheritance is that it is supposed to have poor perform

Re: [linux-audio-dev] apply buys emagic

2002-07-01 Thread Martijn Sipkema
>Apple aquired Emagic. > >no Windows version of any Logic after Sept 30 > >What implies that to us? Any guess? > > haven't seen any other news about it yet. I saw it on http://www.heise.de I sure hope that Emagic will now be willing to give the specifications on their AMT protocol

Re: [linux-audio-dev] RFC: API for audio across network - inter-host audio routing

2002-06-14 Thread Martijn Sipkema
> Going back to the issue of latency, it should be pointed out that while > it might not be a big deal if your softsynth takes 25 ms to trigger, It is unless you only use it with a sequencer. > latency on the PCI bus is a big problem. If you can't get data from > your HD (or RAM) >From memo

Re: [linux-audio-dev] RFC: API for audio across network - inter-host audio routing

2002-06-14 Thread Martijn Sipkema
> if i read this correctly, it's about latency wrt _another_player_. all > trained ensemble musicians are easily able to compensate for the rather > long delays that occur on normal stages. not *hearing_oneself_in_time* > is a completely different thing. if i try to groove on a softsynth, 10 > ms

Re: [linux-audio-dev] RFC: API for audio across network - inter-host audio routing

2002-06-13 Thread Martijn Sipkema
> How about the 1.0-1.5 ms latencies that everbody tries to obtain (or already > has) in both Linux/Win world? That always made me wonder if this isn't just > hype like the 192 kHz issue. > > I'm not a professional musician, but a 25 ms latency makes me more than > happy. I would say that for pla

Re: [linux-audio-dev] RFC: API for audio across network - inter-host audio routing

2002-06-13 Thread Martijn Sipkema
> You certainly can't play an instrument with 10ms > latency. in 10ms sound travels somewhat more than 3 meters. that why i use nearfield monitors :) --martijn

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