On Thursday 04 January 2007 00:32, kind king knight wrote: [...] Well, it's not a single file, it's got a very minimalistic tracker style GUI, and it's using SDL, but it does what it does in about the simplest but (hopefully) correct way: http://olofson.net/mixed.html (DT-42) http://olofson.net/download/DT-42-0.1.0.tar.gz Well, either way, DT-42 uses the SDL audio API. (Which is a lot easier to deal with than OSS or ALSA.) Like JACK and any other serious audio API, this API is callback based. There are some remaining, interesting issues that need fixing. For example, quantization during real time recording (which has to deal with arbitrary audio latency) doesn't really do what it's supposed to. It always rounds down, because the looping implementation isn't safe with recording with "negative delays". (To push a note forward, you'd have to run ahead of the sequencer, looking for loop commands and stuff, or you could end up putting the note some place the sequencer will actually never go.) Another issue is the locking of the sequencer that is done when the GUI messes with things. To make it totaly real time safe, one has to use a different approach. As it is, you might end up with the GUI having a "hickup" while holding the lock that prevents the real time thread from running... Figuring out how to do these things properly might be a good exercise. ;-) Way ahead of you...! :-D I wrote DT-42 almost exactly a year ago. //David Olofson - Programmer, Composer, Open Source Advocate .------- http://olofson.net - Games, SDL examples -------. | http://zeespace.net - 2.5D rendering engine | | http://audiality.org - Music/audio engine | | http://eel.olofson.net - Real time scripting | '-- http://www.reologica.se - Rheology instrumentation --'

On Thursday 04 January 2007 23:30, Frank Neumann wrote: Thanks! :-) That, and maybe DSSIfying the audio and/or sequencer part. Dunno... I suppose it would make it possible to load and play songs without the GUI, which might be handy. OTOH, it would add overhead to the GUI<->engine communication, and the audio and sequencer parts aren't really all that interesting in their own right anyway. (Incredibly simple sampleplayer and 2 operator FM synth with D envelope. The sequencer is like a very simple tracker format with something like 3 commands and no pitch control. :-D) Besides, I have other projects in the pipe, including some DSSI synths, a reimplementation of Audiality (actually more like an audio/music toolkit for EEL) and some other stuff. I'm thinking that the ideas might be more useful than the actual DT-42 code. After all, it was intended as a pure C + SDL example with a minimum of libs and build tools required. The GUI is probably better done in some higher level language and/or using a proper toolkit (now it's plain low level SDL rendering), and the engine could use some refactoring. Then again, there is something about GUI applications written entirely in minimalistic low level code... Reminds of the good old days, when real trackers were implemented in 100% assembly language, and audio and video was done to the metal. ;-) Well, it turned out ok for a "few days" hack, eh? ;-) As to the CPU load, I suspect that the main offender here is actually the song editor, as it lacks "smart refresh" and similar optimizations. IIRC, it pretty much redraws itself completely whenever anything changes, including moving the cursor. Oh, and the FM synth isn't exactly optimized either, float<->int casts, sin() and whatnot... Plenty of cycles to save there. //David Olofson - Programmer, Composer, Open Source Advocate .------- http://olofson.net - Games, SDL examples -------. | http://zeespace.net - 2.5D rendering engine | | http://audiality.org - Music/audio engine | | http://eel.olofson.net - Real time scripting | '-- http://www.reologica.se - Rheology instrumentation --'