Linux-audio-dev

linux-audio-dev@lists.linuxaudio.org

7513 discussions

by A. C. Censi

http://vocamus.net/dave/?p=1092 -- A. C. Censi accensi [em] gmail [ponto] com accensi [em] montreal [ponto] com [ponto] br

15 years, 3 months

autostarting jackd at bootup with Ubuntu/Debian?

by nescivi

Hiho, does anyone have a script lying around to autostart jackd at startup (in Ubuntu/Debian) from a script in /etc/init.d/ ? sincerely, Marije

15 years, 3 months

Re: [LAD] Announcing: ecaedl.pl Edit Decision List Capable Audio Playing

by Robin Gareus

drew Roberts wrote: > On Tuesday 25 May 2010 12:10:26 you wrote: >> drew Roberts wrote: >>> I have been looking for an EDL capable audio player for a while now but >>> have not found one. >> I don't think there's an open-source audio player that does. >> Mplayer has support for EDL but is using it's own homebrew EDL format; >> >> May I ask what you are trying to accomplish? > > Sure. and the answer will make much of the complexity below go away for my use > case. > > I listen to some podcasts that I think it would be useful for some other folks > to listen to as well but people being people, and these people being busy to > boot, they never seem to get around to listening. > > Most of the podcasts are about an hour long. > > What I want to do is listen to the podcasts, mark up an edl to pull out the > parts I think might be most interesting to them and also encourage them to > listen to the whole thing. I guess the easiest would be to just use http://soundcloud.com/ You can add comments on the time-line, tag regions and easily share. see http://soundcloud.com/search?q[fulltext]=podcast for an example. OTOH, this is not a solution worthy of being mentioned on LAD. > I would like to give them a link to the podcast and the edl file and let them > play the audiofile controlled by the edl. You'll want to use SMIL for that: http://www.w3.org/AudioVideo/ As for creating the SMIL-EDL; that'll be the biggest problem.. Making a SMIL template is a one-time job, but finding a good audio-player to generate your in/out timecode is an issue. I don't know if there's a dedicated app for that. Maybe audacity or ardour's cue-files files can be used as a basis. I'm pretty sure there'll be a few projects in the not too distant futures doing this with webm + HTML5. > So, for what I want, the audio playback does not need to be gapless and nor > does it need to be accurate to less than a few seconds. > > Naturally I can see the usefulness of those abilities for other uses. >>> So I hacked together ecaedl.pl which work but is very rough. >>> >>> More info here: >>> >>> http://zotzbro.blogspot.com/2010/05/edl-edit-decision-list-audio-player.h >>> tml >> thanks for sharing. >> >>> pastebin link here: >>> >>> http://pastebin.com/esXJwv84 >> A while ago I went down a very similar road: >> http://rg42.org/gitweb/?p=sodankyla.git;a=blob;f=scripts/vsession.pl >> parses EDL (CMX, CMX3600, Final-Cut-Pro format and 3.0.0) into a sqlite >> database; which can then be used to generate fi. an ardour session. > > One thing I want to play with is if I can make the edl files with the > graphical version of mplayer where I can more easily use the transport > control so that I can make the edl files on the first listening pass and cut > down on my time investment. Perhaps it would be better for me to make the edl > file by hand while listening in another player. >> The workflow there is offline; meaning there's no real-time playback of >> the actual EDL. >> I got a few [filmsound] projects done using these scripts to generate an >> initial ardour-session where the original sound is synced according to >> EDL provided by the film (not video) editor, but I did not have the time >> to go back and clean up the software [yet]. >> >>> Right now this needs ecaplay from ecasound and perl. mplayer is useful to >>> create the edl files but they can be created by hand. >>> >>> Would any cross playform audio player group be willing to add edl playing >>> (and creating) functionality to their player? It would make things much >>> simpler. >> It's not as easy as it may sound. You'll need to be able to perform >> reliable sample-accurate seeking over multiple files and play them back >> without gap. > > As you can see from my particular use case, I anticipate only one audiofile > ever. (I can see that for other uses I might want to work with multiple audio > files, but not this one.) >> If you want to support encoded formats (such as mp3) this can become >> non-trivial very quickly; it can get even worse if the files mentioned >> in the EDL have different sample-rates (that's very unusual, but hey) >> >> I hazard a guess those are basically the reasons why mplayer does not >> support EDL for audio. mplayer's playlist & video-EDL feature allows you >> to mix all kind of codecs/formats: seeking to video-frames (with >> video-frame accuracy is easier). >> >> ciao, >> robin > > Thanks for the discussion and input. >>> (I guess I really need to add in a GPL license section to the file... >>> soonest. >>> >>> all the best, >>> >>> drew > > drew >

15 years, 3 months

Re: [LAD] Looking for an introduction to rt programming with a gui

by torbenh

On Sun, May 23, 2010 at 11:07:27PM +0200, Olivier Guilyardi wrote: > On 05/23/2010 10:22 PM, Chris Cannam wrote: > > [...] > > > ... by which I don't mean to imply that I can't understand it > > (although, with C++, there is always the possibility that I _think_ I > > can understand it but am sadly mistaken because of some weird shit > > happening behind the scenes). I just mean that I can't simply read > > it. > > I once read a great (and funny) article arguing that you simple can't assume > anything about what the following means in C++: > > a = b + c > > Nothing yeah. but if thats not a concatenation or an addition the programmer of the operator overload should be shot on sight. > > > This may be one really serious advantage for the everything-in-C types > > -- a competent C programmer can understand any C, whereas C++ is big > > enough to have many different "schools of C++" which are mutually > > unintelligible without further study. > > > > That's also the seed of its popularity, I suppose -- everyone can > > write the way they like in it, and if you can't work out how to do it > > properly, you can always drop back into C. > > Yeah, C rocks :-) > > But, the problem is that, in my experience, C++ can increase productivity by a > factor of x10 or so over C. It's my personal experience. Very often, I have to > consider making a choice between the two, and I often end up coding the engine > in C and the rest in C++ or a dynamic language. hmm.. i dont really see the advantage of writing an engine in C. first of all you loose RAII locks. http://en.wikipedia.org/wiki/Resource_Acquisition_Is_Initialization then you need to manage most memory yourself again.... could you explain your reasons a bit more ? > > But maybe that, with experience and methodology, one can get as productive in C > as in C++? I suppose the guys at Gnome would agree with that.. there is a reason why gob2 and vala emerged. writing a GObject in C is a pretty big PITA. its probably possible to create the boilerplate out of some kind of template. but i am not aware of some rails/paster like framework to create this boilerplate with a single command. > > -- > Olivier -- torben Hohn

15 years, 3 months

Announcing: ecaedl.pl Edit Decision List Capable Audio Playing

by drew Roberts

I have been looking for an EDL capable audio player for a while now but have not found one. So I hacked together ecaedl.pl which work but is very rough. More info here: http://zotzbro.blogspot.com/2010/05/edl-edit-decision-list-audio-player.html pastebin link here: http://pastebin.com/esXJwv84 Right now this needs ecaplay from ecasound and perl. mplayer is useful to create the edl files but they can be created by hand. Would any cross playform audio player group be willing to add edl playing (and creating) functionality to their player? It would make things much simpler. (I guess I really need to add in a GPL license section to the file... soonest. all the best, drew

15 years, 3 months

Jack slower than realtime/debug mode

by Jeremy

Hi, I'm working on an lv2 plugin, and I'm having some difficulties debugging it. What I would do is start up lv2_jack_host hosting my plugin, and then connect it to an input. However, my plugin isn't returning in time (like, *every single period*), so I get a flood of errors from jack. When I connect it to my microphone, my system actually grinds to a halt, and I have to sysrq in order to get it to respond at all. I also tried loading it as a plugin within qtractor, which causes it to crash qtractor instantly when connected to audio, with no trace. Basically, my plugin right now is completely horrible, and I want to be able to step through it handling one period. Normally I would just fire up gdb, but with jack running in the background, it won't work. Within a few milliseconds of gdb tripping a breakpoint, jack gets mad, and (I believe) stops my plugin from processing to begin the next period. So basically, gdb can't freeze the state, because as soon as I try to, it will unleash a flood of jack errors. What I am hoping for (and it doesn't look like I can find it) is some way to make jack not run in real time, i.e. let it wait indefinitely for clients to process. Obviously the audio output would probably not work, but at least software wise, it seems like this could be viable. Alternatively, a similar setup but on the lv2 plugin level would work, i.e. it could feed in audio data and let the plugin process at whatever speed it wants. Any other suggestions that would allow me to debug my plugin would be welcome (well, besides "code better") Thank You, Jeremy Salwen

15 years, 3 months

Looking for an introduction to rt programming with a gui

by Nathanael Anderson

I've written some small c/c++ programs for my own use that were alsa midi based. I found a very low entry barrier to getting started writing console apps with alsa midi. I'd like to work on something a little larger scale, and include jack midi with a gui to configure options, but have no idea where to start. I'd ideally like to use a loolkit that provides skinable interfaces, and I'm familiar with html/css layout, so something where I can build the gui from a layout file would be nice. If it can handle threading issues for me (rt worker and non rt gui) even better. What choices do I have for tools to use, and what pro's/con's are attached to them. From what i've read so far qt seems like it might be a good choice, aside from the high entry barrier of learning how to do everything the qt way. I'm looking for information on any of the above. Thanks Nathanael

15 years, 3 months

jackd and jackdbus interaction.

by Mike Cookson

Hello. I have installed jackdbus to have working ladish. If I start jackdbus (by "jack_control start" or ladish), legacy jack applications works. But if starting call produced by libjack applications, dbus apps don't see server. If server already started, it should be right for dbus to check first, wether server already runing via libjack and connect to them instead to try start own server to no end. Otherwise (IMHO, should be even more simple), also possible for libjack client functions to work always through dbus. The source of problem is PulseAudio, which I hoped to work only with JACK. I am trying to solve problem with startup script, which kills jackd and starts jackdbus before pulse restarts.

15 years, 3 months

Reminder: upcoming L2Ork workshop at NYC Resistor as part of ICMC 2010

by Ivica Ico Bukvic

(apologies for cross-posting) Dear Colleagues and FOSS enthusiasts, A friendly reminder that we have a Linux Laptop Orchestra (L2Ork) workshop at the NYC Resistor scheduled for May 30th, 2010 as part of the ICMC2010 workshop sessions. Please note the change in time which is 10am-4pm (ET). For additional information and registration info, please consult the website at: http://icmc-workshop-l2ork.eventbrite.com/ I would greatly appreciate it if you would please disseminate this as far and as wide as possible. For more info on L2Ork and its software/hardware resources, please visit: http://l2ork.music.vt.edu Many thanks! Best wishes, Ivica Ico Bukvic, D.M.A. Composition, Music Technology Director, DISIS Interactive Sound & Intermedia Studio Director, L2Ork Linux Laptop Orchestra Assistant Co-Director, CCTAD CHCI, CS, and Art (by courtesy) Virginia Tech Dept. of Music - 0240 Blacksburg, VA 24061 (540) 231-6139 (540) 231-5034 (fax) ico(a)vt.edu http://www.music.vt.edu/faculty/bukvic/

15 years, 3 months

precision resampling to correct clock differences - no luck with libsamplerate and zita-resampler...

by Jörn Nettingsmeier

hi *! i need to re-synchronize two recordings of the same event that for technical reasons had to be done with unsynchronized clocks. i'm assuming for the sake of sanity that both clocks were perfectly stable. my approach is this: in ardour, align some unique feature (a click in this case) at the very beginning of the recordings to within a few samples. set a mark1. then, identify another unique feature close to the end, set mark2 to its position in the reference clock file and mark3 in the file that needs to be resampled. read the frame positions or the markers from session.ardour. sample rate ratio is then (mark2 - mark1) / (mark3 - mark1). i compute a value of precisely 1.00020678091, and i'm now looking for a resampler that will do the right thing here. unfortunately, both zita-resampler and libsamplerate seem to represent the sample rate ratio internally as a fraction of two integers, which means that in my case, it will be rounded to 44100/44107. this is not acceptable for the usecase at hand, as the offset after 4 hours of recording would be too large. due to the massive amount of data to be processed, slicing the material into smaller chunks to reduce the error is not an option. is there a hard technical reason for the behaviour of the resamplers? would it make sense for this bear of very little brain to dig into the code and try to convince them to perform resampling at ratios with full double precision, or is such an undertaking bound to fail? thanks, jörn

15 years, 3 months

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Linux-audio-dev