Linux-audio-dev

linux-audio-dev@lists.linuxaudio.org

1 participants
7517 discussions

by Tom

> It doesn't need an extension to the API, you just have to be able to make > input -> input connections. I belive that makes more sense in an abstract > sense (eqivalent to wiring it that way in hardware) and internaly (reduced > complexity). This will work if the powers that be agree to allow input -> input connections. If not, there is another way. In a hardware mixer, many-to-one connections always require a bus, which is nothing more than a unity gain summing node. Since jack performs unity gain summing for a many-to-one connection, then the buffer that the sum is written to could be redefined as a bus. Then any client could read from the output port of this bus. I am not necessarily in favor of this, nor am I against it. I don't know enough about coding to have an opinion either way. What I do know is that this approach preserves the output -> input semantics. Tom

23 years, 1 month

RE: [linux-audio-dev] Final Scratch, custom kernel?

by Cornell III, Howard M

But encode the time so that it can be read forward or backward. -----Original Message----- From: Steve Harris [mailto:S.W.Harris@ecs.soton.ac.uk] Sent: Tuesday, October 08, 2002 2:52 AM To: linux-audio-dev(a)music.columbia.edu Cc: Paul Winkler Subject: Re: [linux-audio-dev] Final Scratch, custom kernel? On Mon, Oct 07, 2002 at 02:33:54 -0700, Paul Winkler wrote: > Encoding stereo to an LP is no problem - the needle vibrates along > two axes. There's a limit to how much stereo separation you can > get (I forget, it might be like 40-45 dB) but that shouldn't be > too hard to account for. OK, but as long as there are no other restrictions on the channels it should be no problem, something like a saw on one side (to detect speed and corresponding carrier wave speed), and an AM modulated timecode signal on the other. Use the say to calculate the carrier wave for the 2nd channel, then decode the timecode. - Steve

23 years, 1 month

[linux-audio-dev] Tk Ecasound 0.6.0 Released!

by Luis Pablo Gasparotto

Tk Ecasound 0.6.0 was released! Dowload it: http://www.sourceforge.net/projects/tkeca Changes: - Options button works . Allows to edit ecasoundrc file - Entry for selecting current directory - Bug fixes on "Save as" button, open file where there was an existing project, play with choosing a different device (<> /dev/dspN) - Autodetect external audio editor and ladspa directory - Visual changes in effect windows Regards, Luis Pablo Cobertura especial de la Copa Mundial de la FIFA Corea-Jap�n 2002, s�lo en Yahoo! Deportes: http://ar.sports.yahoo.com/fifaworldcup/

23 years, 1 month

Re: [linux-audio-dev] Final Scratch, custom kernel?

by robbins jacob

Interestingly enough, the FinalScratch system does not allow cueing to different positions in the record by lifting the needle up off the record. I saw Richie Hawtin playing on one in DC and I didn't realize what it was at first. I was really perplexed because it seemed like everytime I looked up he was just at the beginning of a record: the tonearm was always very far out towards the edge of the record. Then I figured out that he was using final scratch because he was picking the tracks from a laptop nearby running a program that was basically two lists of tracks. I didn't even think the position signal was running through the audio, I thought they had a separate system magnetically measuring the record position. But it must be something like the saw tooth signal described in this discussion. I wouldn't worry too much about using the cueing of the needle on the record to move through the track. It's more useful on a real record because different sections of a track actually are visible to the naked eye on black vinyl, which jogs your memory into remembering the layout of the track. The final scratch record must have a single loop out at the edge of the record. Such a loop is called a locked-groove when put on a real record: certain styles of dance music have a convenient bpm that allows putting a complete 4 bar pattern into one seamless loop towards the end of the record (the middle). I've only encountered this in techno tracks. There can be a complete track which ends by moving into the lock groove which plays endlessly until the dj stops the record. The beat must perfectly fit one rotation of the record in the lockgroove or else the rhythm will be broken. The same constriction applies to making a lock groove of a control signal. I am convinced final scratch records have a few locked grooves of a control signal at the edge of the record. Adding positional cueing would be a nice feature but consider some of the following circumstances: -you have to put a lock groove at the end of the spiral groove anyway or else you limit the length of track that you can control to some arbitrary amount of time. -if you try to get around this by making a 30 minute track you'll find that the groove is cut smaller so that the record will wear faster and will skip much easier when you scratch it. This is why dance singles have one 6-10 minute track cut on the entire side of a 12" record; record wear is a factor for a dj playing a track many times and bigger grooves hold up longer to repeated playing. They will also sound better longer which is not really an issue here. records tend to wear by pushing towards the outside of the groove from centripedal acceleration. -if you make a 10 minute position-coded section leading into a lock groove you will have to have the standard width of the 10 minute section map to the length of the entire track being played. This means that moving the needle to the middle amounts to saying "move 50% of the way through the track" (which is pretty useful). But it's probably going to end up being easier to cue through the software. Hell it will be easier to do everything through the software. The only advantage I see a turntable controller having is for scratching effects and for dj's who don't want to carry a lot of records. And maybe for beatmatching audio files but programs are leaning towards doing that ahead of time (GDAM). As such I wouldn't worry too much about the positional thing, in favor of getting very tight velocity response for scratching and beatmatching. 8 ms will kill you in beatmatching and final scratch has to have closer than 8 ms "grip" on the audio file being controlled. ~4 ms off is audible phasing. I think it's very interesting to investigate it but it might be easier to just cut a lock-groove control signal and not bother about encoding digital signals on a record. ---jacob robbins;;;;;;;;; _________________________________________________________________ Send and receive Hotmail on your mobile device: http://mobile.msn.com

23 years, 1 month

Re: [linux-audio-dev] Final Scratch, custom kernel? (

by J.F.Quackenbush

---------- Forwarded message ---------- Date: Mon, 7 Oct 2002 23:07:47 -0400 (EDT) From: J.F.Quackenbush <hormonex(a)yankthechain.com> To: linux-audio-dev(a)music.columbia.edu Subject: Re: [linux-audio-dev] Final Scratch, custom kernel? On Mon, 7 Oct I wrote: records include stereo information by having different sounds on each wall of the groove. It seems like teh easiest solution would be to just write SMPTE LTC to one side and something like word clock or black burst on the other. <relurk> I just read this and realize that I was wrong as this reads. One track is recorded in the depth of the groove, the other in the width, so the needle vibrates up and down and side to side simultaneously creating two separate signals. just wanted to clarify. <relurk again> -- /+\-/+\-/+\-/+\-/+\-/+\-/+\-/+\-/+\-/+\-/+\-/+\-/+\-/+\-/+\-/+\-/+\-/+\ YankTheChain.com - You can pretend we're not here. That's what I do. http://www.yankthechain.com/ http://www.digitalblack.org/

23 years, 1 month

Re: [linux-audio-dev] Final Scratch, custom kernel?

by CK

I read: > Well i guess encoding absolute time should not be too hard. > A simple solution could be to have the two stereo channels with different > frequencies, with the ratio corresponding to the radial position. forget it there is no such thing as a clean channel separation on vinyl. regards, x -- chris(a)lo-res.org Postmodernism is german romanticism with better http://pilot.fm/ special effects. (Jeff Keuss / via ctheory.com)

23 years, 1 month

Re: [linux-audio-dev] Final Scratch, custom kernel?

by Juan K.

here's how i do it: 1st channel: 1.5khz control tone 2nd channel: bits encoded as follows: 0 : 1 3khz cycle 1 : 2 6khz cycles marker: 1 1.5khz cycle so each timecode looks like this: marker cycle encoded 0 checksummed bit sequence encoded 1 marker cycle each one ends up being about 8ms. so my "latency" is better than theirs! [i'm pretty sure finalscratch's 12ms assumes the record is moving at normal speed] since the frequencies are multiples of each other, the crosstalk from the cutting head or even from the cartridge that gets used is mitigated the 0 and 1 starter bits help figure out what's going on depending if the record is playing backwards or forwards counting zero crossings works...but don't forget to filter out the low frequencies [like 80hz and below], since the noise from the person's hand will fuck things up i'm fiending to buy one of the finalscratch control records [the guys at platinum are telling me they're gonna be like 25 dollars], to see what they're doing -- John Ketchpaw kungfu(a)alumni.cmu.edu On Mon, 7 Oct 2002, CK wrote: > I read: > > Well i guess encoding absolute time should not be too hard. > > A simple solution could be to have the two stereo channels with different > > frequencies, with the ratio corresponding to the radial position. > > forget it there is no such thing as a clean channel separation on > vinyl. > > regards, > > x > > -- > chris(a)lo-res.org Postmodernism is german romanticism with better > http://pilot.fm/ special effects. (Jeff Keuss / via ctheory.com) > >

23 years, 1 month

[linux-audio-dev] "vst hardware"

by Paul Davis

http://www.plugzilla.com

23 years, 1 month

Re: [linux-audio-dev] meterbridge 0.0.4

by Tom

> > To me, serial metering is a kludge. Taps are the way. Metering is a > > visual form of monitoring. I would like to see jack provide the ability > > > Uggh. There should be no special purpose taps IMHO. In the most generic sense, a tap is simply a read. I would define your alternative drawing as a tap. > I don't have a real problem with connecting to inputs (as long as it > doesn't complicate the graph code too much), but there only needs to be > oneclass of connection. There are already two kinds of connections. If a client's input port is connected to only one output port, the connection is a read. If the client's input port is connected to more than one output port, the connection is a write. This kind of connection, many to one, is where the problem is. I agree that JackPortIsTerminal has nothing to do with this. > > the port reconnection code is evil. i think its completely the wrong > > approach. its just a kludge to avoid using a patch bay. > > > I disagree, its only a kludge because there is no clean way to implement > it with the current API. > > > The insert connection mode is a feature people want (without dicking about > with patchbays) and the reconnection code is a logical extension of that. Insert connection mode for metering is the kludge, metering is parallel. I don't want to use a patch bay (ever), I think that this problem indicates that an api change is called for, and I think that this problem is indicative of a greater general problem regarding the lack of comprehensive monitoring functionality in jack. If Client A's input port is connected to only Client B's output port, then a meter client can effectively monitor A's input port by reading from B's output port. Reading from an output port is allowed so no insert connection is necessary. If A's input port is connected to B and C's output ports, then jack sums B and C's output ports and then writes the result to A's buffer before A begins its process. It is this moment after jack has written and before A begins its process that this buffer could be treated like an output port, and the meter client could read from this port. Of course jack would need to be modified to allow this. The larger issue is this. In a jack client/server network the recording engineer (system administrator) would benefit greatly from having tools that allow monitoring of data traffic at any node in the network, visually and audibly. Not just input or output ports, but any node including different stages of a client process (such as if two plugins are connected in series in an ardour route and I want to monitor the output of plugin 1). The connections to these monitoring tools are made and broken in real time and don't interrupt the graph, as they are terminal. These tools are Solo, Control Room Out, and Meter. Tom

23 years, 1 month

[linux-audio-dev] [ANN] GStreamer graphical pipeline editor released

by Andy Wingo

GStreamer Pipeline Editor "Thanks for all the fish" 0.2.0 released A first release of gst-editor, the GStreamer graphical pipeline editor, is now available for public consumption! This tool allows easy, graphical construction, inspection, and operation of media processing pipelines. It can be used as a rapid prototyping tool as well as a method to learn more about [1]GStreamer. More information about gst-editor is available on the project's [2]home page. Work on gst-editor was originally started in 2000 by Erik Walthinsen, but was left unfinished and unmaintained for a year or two. Development was picked up in mid-2002 by Andy Wingo, resulting in a port to Gnome 2, adaptation to the current GStreamer API, and general UI improvements and modularization. While much progress has been made in the area of stabilization, crashes still occur from time to time. Reproduceable bugs should be reported to [3]Gnome bugzilla. To rehash, for the impatient: THIS CODE IS VERY ALPHA. Screenshots * Thomas Vander Stichele took [4]this shot while designing the pipeline topology for a radio station mixing project: "It shows two decoding threads that read files from disk, connected to an adder, which does threaded output (in the actual app, osssink is replaced again by tee, which sends data to various output methods). "After some experimentation, this seemed to be the ideal pipeline setup, which I was able to verify by setting the whole pipeline to play (using the buttons at the bottom), then only pausing the adder (as shown in the screenshot - see the adder being in pause and everything else in play). Pressing pause here kept osssink playing for a little bit more until the queue is empty. In the app, this gives me the time to disconnect an input pipe, or connect a new one, with the adder being paused, so as to have seamless playback." * Andy made [5]this shot while playing around with [6]LADSPA plugins. Note the automatically generated controls for element properties, as well as the quick launch palette showing all available elements. Download gst-editor requires GStreamer 0.4.1. It could probably work with 0.4.0, but that is untested. You can find the source release of gst-player in [7]tar.gz format. RPM packages will be available from our [9]apt for rpm repository, and Debian packages should be coming soon to an experimental near you. Maintainer needed Andy is heading off to teach physics in rural Namibia for two years. Needless to say, he won't be doing much development on the editor. Patches should be submitted to the [10]gstreamer-devel mailing list. References 1. http://gstreamer.net/ 2. http://gstreamer.net/apps/gst-editor/ 3. http://bugzilla.gnome.org/enter_bug.cgi?product=GStreamer&component=gst-edi… 4. http://gstreamer.net/images/gst-editor-gstreamix.png 5. http://gstreamer.net/images/gst-editor-ladspa.png 6. http://www.ladspa.org/ 7. http://prdownloads.sourceforge.net/gstreamer/gst-editor-0.2.0.tar.gz?downlo… 8. http://prdownloads.sourceforge.net/gstreamer/gst-editor-0.2.0.tar.bz2?downl… 9. http://gstreamer.net/releases/redhat/ 10. http://gstreamer.net/contact/lists.php

23 years, 1 month

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Linux-audio-dev