From d2a88cfaad5ac385fc3c6212c09ad7fbc38e9454 Mon Sep 17 00:00:00 2001 From: Florian Jung Date: Mon, 28 May 2012 14:15:52 +0000 Subject: merged with release_2_0 --- muse2/doc/documentation.tex | 502 ++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 502 insertions(+) create mode 100644 muse2/doc/documentation.tex (limited to 'muse2/doc/documentation.tex') diff --git a/muse2/doc/documentation.tex b/muse2/doc/documentation.tex new file mode 100644 index 00000000..49d26964 --- /dev/null +++ b/muse2/doc/documentation.tex @@ -0,0 +1,502 @@ +%% (c) 2012 florian jung +%% we should consider putting this under a proper license. GPL, or +%% some GPL-like documentation license?? + +%% rules for editing documentation: (READ THIS FIRST) +%% ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ +%% +%% please try to let newly written lines be shorter than 72 characters. +%% minor exceptions are okay, but please not more than 80 chars. +%% comments shall start after character #80 of the line (that is, +%% they shall be "on the right margin") +%% +%% DON'T MIX up changes and reformatting in one commit. when changing +%% stuff, please don't touch the lines before and after your change +%% (that is, do not re-wrap them), even if it will look a bit patchy. +%% this is for being able to easily use diff. +%% when you want to reformat this file, then do it. but don't change +%% anything, as this would be hard to find in a diff. and clearly +%% state in the commit log that you "only" rearranged things. +%% +%% please adhere to the "User's manual" / "Internals" / "Design" +%% partitioning (genereally, don't change the chapters until there +%% is a really good reason for doing so (adding a chapter like +%% "feature requests" as flo did in r1497 IS one). +%% Below that, feel free to change the logical arrangement +%% (making paragraphs to subsections and similar) if you deem it +%% neccessary. +%% +%% Whenever referring to code symbols, constants or source/header +%% files, please use \texttt{someClass::someSymbol} or \texttt{file.cpp} +%% Only specify file paths or namespaces where it would be ambiguous +%% otherwise. Specify 'someClass::' until it would disturb the reader +%% and it is obvious. (watch out to prefix _ with \) +%% +%% Where possible, reference other parts of this documents with +%% \label and \ref. Avoid duplicate information under "Internals" by +%% referring to the appropriate section in "User's manual". +%% +%% Please do no time-stamping of sections. if you need time-stamps, +%% use "svn blame documentation.tex" +%% +%% If you contribute something, feel free to add yourself to \author. +%% +%% If you don't speak LaTeX fluently, a few tips: +%% * \section, \subsection, \subsubsection, \paragraph, \subparagraph +%% let you create sections etc. just copy-and-paste if unsure. +%% * you must prefix special characters like the underscore with \ +%% (backslash) +%% * \emph{some text} emphasizes the text, printing it italic. +%% * \texttt{some text} displays the text in a typewriter font +%% * \label{someName} creates a label at this position. this doesn't +%% show up in the pdf. with \ref{someName}, you can reference to this +%% label. (LaTeX will insert the section number instead of \ref) +%% For this to work, you might need to recompile the .tex twice. +%% +%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% + + + +\documentclass[a4paper]{report} +\usepackage[T1]{fontenc} +\usepackage[utf8]{inputenc} +\usepackage{lmodern} +\usepackage[english]{babel} +\author{Florian Jung} +\title{MusE Documentation} +\begin{document} + +\chapter{User's manual} +someone should really write this! + +\section{Basic overview} +\subsection{Tracks} +MusE arranges your music in \emph{tracks} and \emph{parts}. The following +section shall provice you an overview of how things are done with MusE. +If you are or were a Cubase or Cakewalk user, you will feel familiar with +this. There are +MIDI and drum tracks (which are internally MIDI tracks) which can hold +note data, wave tracks which hold wave data, and several kinds of +audio tracks, synthesizers etc. + +\paragraph{MIDI tracks} +MIDI and drum tracks hold MIDI event data. They don't differ much, +except that drum tracks offer a special editor which is more suitable +for drum editing. + +\paragraph{Wave tracks} +They hold audio data which can be just played back or be piped through +effect plugin chains. They offer automation for these plugins. + +\paragraph{Audio inputs} +These provide the path for your audio data from outside into your +project. Set up the physical audio inputs you want to connect your audio +in track with, and then route them to some wave tracks. + + % TODO: what are audio outs and auxs? + % someone please write this! + +\subsection{Parts} +Tracks are split in parts. These contain MIDI events or wave chunks. +You can copy, clone them, move them around, delete them etc. + +\subsection{MIDI ports} +Ports provide an abstraction layer for your MIDI synthesizers (which +can be both software and hardware synthesizers). Port are numbered. +In order to produce sound, each MIDI track is assigned to exactly one +MIDI port, to which the MIDI events are then sent. + +In the configuration menu, you must map the port numbers to the actual +synth devices (by selecting ALSA or jack midi ports, or synth plugins). + +Try left-clicking on the "Ports" column of some MIDI track. If you +use a soft synth, right-clicking the Ports column of the synth or any +track using the synth lets you launch the synthe's GUI. + +\section{Tracks and parts} +\subsection{Tracks} +\paragraph{Creation} +You can create a track by either right-clicking in the arranger's track % TODO: insert screenshot +list and then adding the desired track, or via the edit menu. + +\paragraph{Attributes} % TODO: this should be a list +Tracks have several attributes. +\subparagraph{Mute} If you click on the \emph{Mute} field (denoted with +a "M" column header), the track gets muted and stops producing sound. +\subparagraph{Solo} The solo button ("S" column header) mutes all other % TODO: soloing chains etc? +tracks. +\subparagraph{Record} The R column "arms" your track for recording. +When you rec-arm your song and have no tracks rec-armed, you won't be +able to record anything. See also the config option "move rec-arm with % TODO: reference to rec-arm config option +selection". +\subparagraph{Track name} Double-click and you will see. +\subparagraph{Port} For MIDI tracks, this lets you select the MIDI +port to which the events should be routed. This can be your physical +synthesizer or a software synthesizer. For soft synthes, this is the +port the synth is associated to. For other track types, this is disabled. +\subparagraph{Channel} For MIDI tracks, this is the MIDI channel the +output is sent to. For any kind of audio tracks, this is the number of +channels (mono, stereo). + % TODO: what's that "T" column?! +\subparagraph{Automation} For audio tracks, this lets you set up the +automation display in the arranger. Clicking this will provide you with +a popup menu with lots of submenus. The submenus let you select the +color you want to associate with the automation parameter. \emph{Clicking % TODO: this is nonstandard +on a submenu} will select or unselect it, making the automation parameter % TODO: put reference to automation section +shown or hidden. + +\subparagraph{Clef} For MIDI tracks, you can specify a clef here. This +only affects the score editor. + +\paragraph{The trackinfo side bar} +In the arranger and the part editors, you'll have a trackinfo sidebar +on the left side. You can set up track-type specific things there. + +\subsubsection{MIDI tracks} +MIDI parts have no automation settings. However, they support various % TODO: this will hopefully become wrong soon +controllers, program changes etc.. The MIDI trackinfo sidebar lets you +change program, volume, pan and more. Just editing the value in the +boxes will send an event, but not write it to the track. In order to +write it, you will need to click on the corresponding button ("Vol" for +writing down volume information). + +\subsubsection{Old style drum tracks} +These are MIDI tracks as well, but with a few differences. They allow +you to map certain drum sounds with different input notes, and you +can change the output settings of a certain "drum instrument" without +having to alter each single event. + +However, they have certain limitations: They only can handle 128 sounds +(even if you have more synthes), they aren't really compatible with +MIDI tracks (you can interchange parts between them, but if you touched +the drum list, you'll get unexpected results), you can't set a program +for the used channel and more. + +\subsubsection{New style drum tracks} +That's why there will be new-style drum tracks in the next development version. % TODO: in trunk, change this +They are handled exactly like plain MIDI tracks (staying compatible with +them), and offer all of the functionality, though in a different way. +They allow you to re-order the drum map efficiently, you can open parts +from multiple drum tracks in \emph{one} drum editor (MusE will separate +the sounds from different tracks according to your settings, see the +"Window Config" menu), and you can set programs as with normal MIDI tracks. + +\subsubsection{Audio tracks} +\paragraph{Effect rack} +On the top of the sidebar, there is an effect rack which allows you to +apply various plugins on the audio. For more information on this, refer +to \ref{plugins}. + +\paragraph{Controls} +Lorem ipsum % TODO FINDMICH HIER WEITER + + +\subsection{Parts} +Within MIDI, drum and wave tracks, you can create \emph{parts}. Parts +are chunks of coherent notes or wave data which can be moved around, +copied, cloned and deleted independent from other parts. + +Parts are created by selecting the pencil tool and then drawing onto +the right part area in the arranger. You can move them with the arrow +tool, delete them using the \texttt{DEL} key, and a right-click opens +a popup menu. This menu allows you even more stuff, such as setting +the part's color, saving the part to disk etc.. You can use +\texttt{CTRL+C} and \texttt{CTRL+V} for copying and pasting parts. +\texttt{CTRL+B} pastes the part as a clone. Pressing \texttt{SHIFT} +additionally provides you a dialog which allows you to paste the part +multiple times and set more stuff. + +You can also copy parts with the mouse by moving the part with the mouse +while holding down the \texttt{CTRL} key. + + + +\section{Plugins and automation} \label{plugins} +There are several kinds of plugins. First, there are audio plugins, which +can be applied to any track handling audio (that is, inputs, outputs, +wave tracks, synth tracks). Plugins can be added by double-clicking +on an entry in the effect rack in the track info pane (which is shown +at the left side of the arranger when the according track is selected). +Right-clicking them offers a self-explanatory popup menu. + +\section{Configuration} +\paragraph{Minimum control period} +Plugins can usually process an arbitrarily small (or large) amount of +samples. If some plugin control value changes continously, to provide +ideal listening experience, MusE would need to call the plugin 44100 +times a second, asking for one single value at a time. With the minimum +control period setting, the user can force MusE to ask the plugin for +at least N values. Setting this value to 64 would in this situation +make MusE call the plugin $689 = \frac{44100}{64})$ times a second, +asking for 64 values at a time. While doing this will reduce accuracy +of control changes, it may also reduce CPU usage, because calling +the plugin more often, requesting smaller chunks, is more expensive +than calling it seldomly, requesting larger chunks. +\subparagraph{Recommendation} +If you have no performance problems, or if you want to do the final +downmix of your project, set this to a low value. If you're experiencing +performance problems, increasing this value might help. + + + + + + +\chapter{Internals -- how it works} +This chapter explains how MusE is built internally, and is meant +to be an aid for developers wanting to quickly start up with MusE. +For details on \emph{why} stuff is done please refer to the following +chapter. +\section{User controls and automation} +\subsection{Handling user input} +\paragraph{Plugins and synthesizers} +When the user launches a plugin's GUI, either a MusE-window with +the relevant controls is shown, or the native GUI is launched. MusE +will communicate with this native GUI through OSC (Open Sound Control). + +The relevant classes are \texttt{PluginGui}, \texttt{PluginIBase} +(in \texttt{plugin.h}) and \texttt{OscIF} (in \texttt{osc.h}). + +If the user changes a slider, first the corresponding control is +disabled, making MusE not steadily update it through automation +while the user operates it. \texttt{PluginIBase::setParam} is called, +which usually writes the control change into the ringbuffer +\texttt{PluginI::\_controlFifo}. (\texttt{PluginI::apply()}, +\texttt{DssiSynthIF::getData()} will read this ringbuffer and +do the processing accordingly). Furthermore, the change is written +into a "to be recorded"-list (done by calling \texttt{AudioTrack::recordAutomation}). +This list is processed after recording has finished. %TODO: where and when exactly? + +Disabling the controller is both dependent from the current automation +mode and from whether the GUI is native or not. +In \texttt{AUTO\_WRITE} mode, once a slider is touched (for MusE-GUIs) or +once a OSC control change is received (for native GUIs), the control +is disabled until the song is stopped or seeked. + +In \texttt{AUTO\_TOUCH} (and currently (r1492) \texttt{AUTO\_READ}, but +that's to be fixed) mode, once a MusE-GUI's slider is pressed down, the +corresponding control is disabled. Once the slider is released, the +control is re-enabled again. Checkboxes remain in "disabled" mode, +however they only affect the recorded automation until the last toggle +of the checkbox. (Example: start the song, toggle the checkbox, toggle +it again, wait 10 seconds, stop the song. This will NOT overwrite the +last 10 seconds of automation data, but everything between the first +and the last toggle.). For native GUIs, this is a bit tricky, because +we don't have direct access to the GUI widgets. That is, we have no +way to find out whether the user doesn't touch a control at all, or +whether he has it held down, but just doesn't operate it. The current +behaviour for native GUIs is to behave like in \texttt{AUTO\_WRITE} mode. + +The responsible functions are: \texttt{PluginI::oscControl} and +\texttt{DssiSynthIF::oscControl} for handling native GUIs, +\texttt{PluginI::ctrlPressed} and \texttt{ctrlReleased} for MusE +default GUIs and \texttt{PluginI::guiParamPressed}, +\texttt{guiParamReleased}, \texttt{guiSliderPressed} and +\texttt{guiSliderReleased} for MusE GUIs read from a UI file; +\texttt{guiSlider*} obviously handle sliders, while \texttt{guiParam*} +handle everything else which is not a slider. They call +\texttt{PluginI::enableController} to enable/disable it. + +Furthermore, on every song stop or seek, \texttt{PluginI::enableAllControllers} +is called, which re-enables all controllers again. The call paths for +this are: +\begin{itemize} +\item For stop: \texttt{Song::stopRolling} calls + \texttt{Song::processAutomationEvents} calls + \texttt{Song::clearRecAutomation} calls + \texttt{Track::clearRecAutomation} calls + \texttt{PluginI::enableAllControllers} +\item For seek: \texttt{Audio::seek} sends a message ("\texttt{G}") to + \texttt{Song::seqSignal} which calls + \texttt{Song::clearRecAutomation} which calls + \texttt{PluginI::enableAllControllers} +\end{itemize} + + + + +\chapter{Design decisions} +\section{Automation} +As of revision 1490, automation is handled in two ways: User-generated +(live) automation data (generated by the user moving sliders while playing) +is fed into \texttt{PluginI::\_controlFifo}. Automation data is kept +in \texttt{AudioTrack::\_controller}, which is a \texttt{CtrlListList}, +that is, a list of \texttt{CtrlList}s, that is, a list of lists of +controller-objects which hold the control points of the automation graph. +The \texttt{CtrlList} also stores whether the list is meant discrete +(a new control point results in a value-jump) or continous (a new control +point results in the value slowly sloping to the new value). + +While \texttt{PluginI::\_controlFifo} can be queried very quickly and +thus is processed with a very high resolution (only limited by the +minimum control period setting), the automation value are expensive to +query, and are only processed once in an audio \emph{driver} period. +This might lead to noticeable jumps in value. + +This could possibly be solved in two ways: +\paragraph{Maintaining a slave control list} +This approach would maintain a fully redundant slave control list, +similar to \texttt{PluginI::\_controlFifo}. This list must be updated +every time any automation-related thing is changed, and shall contain +every controller change as a tuple of controller number and value. +This could be processed in the same loop as \texttt{PluginI::\_controlFifo}, +making it comfortable to implement; furthermore, it allows to cleanly +offer automation-settings at other places in future (such as storing +automation data in parts or similar). + +\paragraph{Holding iterators} +We also could hold a list of iterators of the single \texttt{CtrlList}s. +This would also cause low CPU usage, because usually, the iterators only +need to be incremented once. However, it is pretty complex to implement, +because the iterators may become totally wrong (because of a seek in the +song), and we must iterate through a whole list of iterators. + +\paragraph{Just use the current data access functions} +By just using the current functions for accessing automation data, +we might get a quick-and-dirty solution, which however wastes way too +much CPU ressources. This is because on \emph{every single frame}, we +need to do a binary search on multiple controller lists. + + +\chapter{Feature requests} +\section{Per-Part automation and more on automation} % by flo +Automation shall be undo-able. Automation shall reside in parts which +are exchangeable, clonable etc (like the MIDI- and Wave-Parts). +Global per-synth/per-audiotrack automation shall also be available, but +this can also be implemented as special case of part automation (one +long part). + +\section{Pre-Rendering tracks} +\subsection{The feature} +All tracks shall be able to be "pre-renderable". Pre-rendering shall +be "layered". Pre-rendering shall act like a transparent audio cache: +Audio data is (redundantly) stored, wasting memory in order to save CPU. + +That is: Each track owns one or more wave-recordings of the length of +the song. If the user calls "pre-render" on a track, then this track +is played quasi-solo (see below), and the raw audio data is recorded +and stored in the "layer 0" wave recording. If the user has any effects +set up to be applied, then each effect is applied on a different layer +(creating layer 1, layer 2 etc). + +This means, that also MIDI and drum tracks can have effects (which +usually only operate on audio, but we HAVE audio data because of this +prerendering). + +Furthermore, MusE by default does not send MIDI events to the synthesizers +but instead just plays back the last layer of the prerecording (for +MIDI tracks), or does not pipe the audio data through the whole plugin +chain (causing cpu usage), but instead just plays back the last layer. +The hearable result shall be the same. + +Once the user changes any parameter (automation data or plugins for +wave tracks, MIDI events or effect plugin stuff for MIDI tracks), +then MusE shall generate the sound for this particular track in the +"old" way (send MIDI data to synthes, or pipe audio data through plugins). +(So that the user will not even notice that MusE actually pre-renderered +stuff.) Either MusE automatically records this while playback (if possible) +or prompts the user to accordingly set up his cabling and then record +it. Or (temporarily) disables prerecording for this track, falling back +to the plain old way of generating sound. + +\emph{Quasi-solo} means: For wave tracks, just solo the track. For MIDI +tracks, mute all tracks which are not on the same synth (channel?), +and mute all \emph{note} events which are not on the quasi-soloed track. +This causes MusE to still play any controller events from different +tracks, because they might have effects on the quasi-soloed track. (You +can have notes on channel 1 on one track and controller stuff on channel +1 on another track; then you would need quasi-solo to get proper results.) + +\subsection{Use cases} +\paragraph{Saving CPU} +On slow systems, this is neccessary for songs with lots of, or demanding +(or both) soft synthes / plugins. Even if the synth or plugin is so +demanding that your system is not able to produce sound in real-time, +then with this feature you'll be able to use the synth (this will make +editing pretty laggish, because for a change you need to re-render at +least a part before you can listen to it, but better than being unable +to use the synth at all!) + +\paragraph{Exporting as audio project} +Using pre-rendering on all tracks, you easily can export your project +as multi-track audio file (for use with Ardour or similar DAWs). +Just take the last layer of each track, and write the raw audio data +into the file, and you're done. (Maybe we are even able to write down +the raw-raw layer0 audio data plus information about used plugins and +settings etc..?) + +\paragraph{Mobile audio workstations} +You might want to work a bit on your audio projects on your notebook +while you're not at home, not having access to your hardware synthesizers. +Using this feature, you could have pre-recorded the stuff in your studio +before, and now can at least fiddle around with the non-hw-synth-dependent +parts of your song, while still having your \emph{full} song with you. + +\paragraph{Applying effects on MIDI tracks} +If you have many physical audio inputs, you might already be able to +apply effect chains on MIDI tracks, by wiring the synthes' audio +outputs to your soundcard's inputs, and applying the effects on +dedicated input tracks you have to create. This requires you to have +expensive hardware, and is pretty complicated, because you need one +additional track per MIDI synth. + +This feature allows you to apply effects on single MIDI tracks, and not +only on full MIDI synthes, and doesn't require you to be have that +many physical audio inputs (you need to manually replug your synthes, +however). + +\subsection{Possible scenarios} +\paragraph{Setting it up} +Create a wave track, MusE will allow you to set or unset prerendering +for every plugin in the plugin rack (recording the actual track is +useless because it would be a plain copy). +Create a MIDI track, MusE will ask you on which physical audio input +your synth is connected. Setting up multiple synthes on one physical +audio in is allowed, see below. + +\paragraph{Pre-rendering stuff} +When the user presses the "pre-render" button, all tracks which have +been changed since their last pre-rendering will be re-rendered. +If you have multiple hardware synthes set up as they were connected +to one physical audio input port, MusE will prompt you to first plug +the proper cable in. + +\paragraph{Making changes} +Change a note in a MIDI part, move or delete a part or change automation +parameters. MusE will temporarily disable the pre-rendered information +and instead generate the sound via sending out MIDI events, piping stuff +through effect chains or similar. If you play back the whole song, or +if you manually trigger a re-rendering of a track via the context menu, +MusE will play back the stuff, record it again and re-enable the +pre-rendered information. + + +\section{Extensions} +\paragraph{Automatic discovery of physical audio connections} +The user plugs all (or only some) synthes' audio outs into the available +audio inputs, then runs automatic discovery. This will send MIDI events +to each synthesizer, and look on which audio in there's activity. Then +it will assume that the synthesizer is connected to that particular +audio in. Audio ins which show activity before any MIDI events were +sent are not considered, as they're probably connected to microphones +or other noise-generating non-synthes. + +\paragraph{Audio export} +As described in the Use cases, MusE can allow you to export your song +in some multitrack audio format. + +\paragraph{Cheap/Faked changes} +For expensive or unavailable synthes, changing the Volume midi controller, +the Pan controller or similar "easy" controllers will not trigger a +complete re-rendering, but instead "fake" the change, by changing +the volume data directly on the recorded wave. This might require some +learning and might even get pretty complicated. + +\paragraph{Intelligent re-recording} +For tiny changes, MusE shall only re-render the relevant part. If you +change some MIDI notes, then begin re-recording shortly before the +changes, and end re-recording as soon as the recorded stuff doesn't +differ to much from the stuff coming from the synth. Then properly +blend the old recording with the updated part. + +\end{document} -- cgit v1.2.3