QRt

A Cross-platform Sound Mixing Tool


Contents

Introduction

QRt is a QT window system port of Rt, Paul Lansky's mixing tool, which was originally designed for the NeXT platform, and subsequently ported to SGI and Linux. QRt will run under X86 Linux (under X Windows) and MacOSX (natively).  It allows the user to play large numbers of different soundfiles, up to 16 at a time (or more, depending on the number of configured tracks) as if they were notes, from a note list, with continuous control over amplitude, pitch, input and output skip, pan, and direction. QRt can be compiled to handle any number of (stereo) tracks. (For now, versions greater than 12 tracks still only have controls for 12 tracks on the second page, but all tracks can be controlled from the Track Map Window.)

The data is organized in terms of sounds and tracks.  A track can only play one mono or stereo sound at a time. A segment of a sound played on a given track at a given time will be referred to as a note or playnote.

With this program you can:

  1. Mix arbitrary parts of soundfiles of different sampling rates and of different formats (mono and stereo)
  2. Put envelopes on sound segments.
  3. Continuously control gains of left and right channels independently.
  4. Continuously control gains of tracks independently, and alter gains over periods of time.
  5. Shift the pitch of a note up or down, continuously or instantaneously.
  6. Selectively listen to given tracks and/or given sounds.
  7. Save and restore the state of a given mix in an ascii data file
  8. Write a mix to disk, or to the audio hardware and the digital i/o port.


The Menus




The Four Windows



The Main Window

The Track Control Window

Contains gain controls for each channel of the first 12 tracks and the 2 output tracks as well as reports on peak amplitudes and mute switches for each track.

The Playnote Editor Large View Window

A larger version of the playnote editor, plus transport controls.

The Track Map Window

A visual display and editor for soundfile segments on tracks, and a moving cursor while playing mixes.


Main Window



Soundfile Table


The path names of the relevant soundfiles are listed in the soundfile table. The number of the soundfile is important and is used by playnote to reference that soundfile. Soundfiles can be loaded by using the Load Input Soundfiles command in the Soundfiles menu, or by dragging sound icons into the track map window. To load a new soundfile at a specific location in the soundfile table, right-click on the soundfile and choose Replace... from the popup menu.  If you want to load a place holder at some point, choose Set to 'null' from the same menu.

Soundfiles can be auditioned directly from the soundfile table by simply double clicking on the name of the soundfile. Double click again to stop playback.

Soundfiles can be turned off and on either during or before a mix is played by choosing Toggle on/off from the popup menu.

The gain column is editable. You can change a gain by selecting and typing over, or inserting, or, you can place the cursor in the gain and move the slider above the gain column to change that gain. These gains control the amplitude of that soundfile, and are multiplied by the gain factor on the playnote card, the track gain for a given playnote and the output gain. To fine-tune a gain you can click to the right and left of the slider indicator on the soundfile gain slider.
The gain change will take place during a play with delay subject to buffer size -- see lookahead buffers -- if you change it with the slider. Otherwise it will only take effect on the next play.


Playnote Editor


In the playnote editor you type in the actual commands for accessing and mixing the soundfiles. Each playnote command is usefully thought of as a note. It instructs the sound driver to play part or all of a soundfile at a given time, on a given track, with certain properties. You can copy and paste text into the playnote editor. The arguments can be placed in any order. Both the playnote editor and the large playnote editor use Emacs key bindings.

Each playnote command must appear on a separate line in the playnote editor. It needn't begin in the first column.

The only required argument for a playnote command is the the sound number (snd=x). All other arguments have default values if omitted.

Each note as specified by a playnote command has the following properties, specified with these tags:

If you have both a gliss() and transp=argument, then they will be added. All pitch values in the gliss() curve will have the transp= value added to them.

Example:

amp(0,.2,2,.5, | , 9, 1, 10, 0) means that this note will have a rise from .2 to .5 over the first 2 seconds, and have a decay from 1 to 0 over the last 1 second of the note, (assuming its duration is at least 3 seconds), and between these two times the amplitude will go from .5 to 1. If for example the note is 20 seconds long, this is equivalent to saying amp(0,.2,2,.5,19,1,20,0).

If there were not a stickpoint in the above example and the note were 20 seconds long, it would equivalent to saying amp(0,.2,4,.5,18,1,20,0). Here you can see that the times are warped relative to the actual duration of the note. There can be only one stickpoint in an argument set, but there can be any number of argument pairs around it.

playnote(snd=1,track=1,skip=2.5,at=3.5,amp(0,0,1,1,2,0),dur=4)

will cause snd 1 to be played on track 1, starting at 2.5 seconds into the sound, starting at time 3.5 in the mix, for 4 seconds with an envelope going from 0 to 1 and back down.

playnote(track=1,snd=1,transp=-2.5)

will simply play all of snd 1 on track 1 down 2.5 semitones.

The commands in the playnote editor are initially loaded by hitting the load everything, or reload playnotes buttons in the control window. If some of the text in the playnote editor is selected, only that portion will be loaded. You can subsequently select a subset of the playnote commands in the playnote editor to be added to the mix, or altered within the mix by simply selecting them with the cursor and hitting the reload playnotes button. This will save a bit of time since it sometimes takes a few seconds to load in a bunch of files and playnote commands. Note that if a subsequently loaded playnote command occupies the same time portion of a track as a previous one, then the first one will be eliminated.

Some Special Features

When either of these arguments is used the actual computed at value will appear in the output window. I recommend pasting this into your playnote, replacing the last or overlap definitions, to avoid too much confusion. Things can get messy, particularly in connection with the offset= command (see below).

Additional commands which can appear in the playnote editor

These arguments are specified on separate lines, not within a playnote argument list, and will effect all playnote commands which follow.

Safety Backup

After every 25 characters are altered or entered in the playnote editor, a complete backup of the current rt script will be saved in the /tmp directory. It will be called <filename>.bk if you opened a script called filename., and untitledxxxx.rt.bk, where xxxx is some arbitrary number, if you a creating a new unnamed script.


Information Window


This window displays status and error messages.  This window displays reports on syntax errors from the playnote parse, and indicates when sound and mix playback begins and ends.  Note that if a window other than the Main Window is on top, syntax errors are also displayed via a popup window.


Track Control Window



It is not necessary to use this window, but it can provide some extra gain control. It is opened by clicking on the tab at the bottom of the main window. You can also mute tracks by clicking on the track number atop each set of sliders. The changes you make only go into effect a few seconds after you make the change, due to the large size of the intermediate sound buffers used to do the mix.

The track control window is quite useful for balancing sounds, and for preparing very complicated mixes which might exceed the throughput capacity of the machine. You can turn selected tracks off and on, balance them against each other etc.


Playnote Editor -- Large View


 


The third window is simply a larger version of the playnote editor on the main page. The purpose of this is to allow you to look at larger groups of playnotes without having to scroll around.  When you toggle back and forth between this and the main window, each is updated.


Track Map Window




In many ways this is the most powerful window in qrt.  Here you can see a visual representation of your playnote commands, visually edit the start time, duration, track number, and gain of any playnote, and add new playnotes via the playnote text entry.

Display in the Track Map Window

Once playnotes have been loaded with the load everything button, or with the reload playnotes button, this window will display a timeline layout of the tracks and soundfile segments on each track. Below each soundfile are two numbers indicating starting time and duration for that segment. While playing, a cursor will sweep across the screen, and the time will be displayed in the lower left hand text field. If you click the left mouse button anywhere in the window, the next play will begin at the time you clicked and the starting time will be displayed in the right of the two text fields. (You can also simply type a number in that window to force a starting time.)  Remember that if you are skipping into a mix, there may be a pause before it starts to play. If you click the left mouse button while a sound is playing it will stop playing. While playing, if you click the right mouse button anywhere in the window, the mix will start to play at this point. If it is already playing it will stop and start again at the point at which you clicked. This enables you to jump around a mix. Again, there may be some slight delay, depending on your timescale, and the size of the timeskip.

On the lower right hand side of the window there is an autoscroll switch. Toggling this on will cause the window to scroll to a location during playback in which the moving cursor is always visible.

The zoom in and zoom out buttons will give you differently scaled displays.  When you are zoomed out the smallest visible duration may be about 1/4 inch wide. In the zoom out case the time and duration of each note will not be displayed.  Holding down the <shift> key while using these buttons will zoom you in and out by 50% (rather than 10%).

If you have a comment after a playnote: e.g.

playnote(track=1,snd=2,at=23,skip=23)//big noise

this comment will appear above the bar representing the playnote. If there is no comment, the soundfile name will appear, stripped of its full path.  In all cases, the text is preceded by the sound number in brackets.  For example, the playnote listed above would have the text "[2] big noise".  Sometimes, depending on the length of your comments and filenames, and the length (duration) of the playnote, the end of the text will be truncated (clipped). The comments are always clipped to the length of the playnote's visible rectangle.  Zooming in the display usually fixes this, or reducing the size of the font used to display text in the track map window (see below).  There are also cases when the end of one playnote will overlap the beginning of another. These should be obvious, and can be checked using the Show Note Overlaps menu command.

The font for the text in the track map window can be set in the resource file using "trackMapFont", and set via the Set Editor Font menu command. The names need to match the QT font specification.

The shape of the bars in the track map window reflects the amplitude modifications you have made in the playnotes with the amp() command, with the apparent height of the bar representing its amplitude relative to the maximum specified by the time, amp pairs.

The color of the bars reflects the gain as stated in the gain= command, as modified by the input soundfile gain and the track gain from the Track Control Window.  Using the default color scheme, bright tan is light and dark brown is soft, with various shades in between reflecting gains in between. This color scale can be modified by editing the resource file (see Customizing).

 Editing existing playnotes in the Track Map Window

Several attributes of a playnote can be easily changed from this window. If you shift-click the left mouse button on any playnote bar, the playnote script for that note will appear in the textfield below and the soundfile name and number in the lower field to the right. You can then edit it. When you press the reload playnotes or reload everything button the changes will take effect. If you want to make a bunch of changes in several playnotes you can enter the changes into memory by just editing them all, then hitting either of the two reload buttons to make all the changes at once.

You can play the playnote or the soundfile by itself with the play buttons to the left of each field. In the case of the playnote, what is happening is that you are playing the mix with all the other tracks turned off, and skip and end set to that playnote's time. Note that if you have a small timescale, and a lot of tracks and sound, there may be a delay before it starts to play. (Skips are much faster with larger timescales.). The playnote playback can be stopped using the stop button;  the soundfile playback is stopped by pressing the play button again (note that its text had changed to "stop"). You can also audition the playnote by pressing the <space> bar, and stop it by pressing it again.  If you hold down the shift key while clicking on the play button, the note will start to play at the time specified in the skip field, rather than at the beginning of the note. This way you can play selected portions of a playnote as well.

There are several causes of potential confusion when using this page. First, the reload playnotes button may not erase old playnotes from memory, but they may not appear on the map. If, for example, you change tracks, the playnote may still live on the old track as well but will not appear on the map (unless it previously overlapped the end of an earlier playnote, in which case it will not sound). The only way to make sure that your map is accurate is to hit the reload everything button. This is not necessary, however, if you are just changing amplitude characteristics, or making the starting time a bit earlier.

If, on the main page, you loaded the playnotes after having made a selection in the playnote editor, what you will see is the result of that selection. Changes in any playnotes will, of course, be copied back to the playnote script, whether or not a selection is in effect.

Another potential source of confusion is in the case where you want to simply reload one playnote in the main window by selecting that playnote and hitting reload playnotes. In this case only that playnote will appear in the track map, although all the other playnotes selected previously will still sound. (This should be fixable, but my brain hurts right now.)

This window makes it very easy to fine tune characteristics of a mix. You can mute and/or solo tracks with the buttons to the left of each track, and start at any time in the mix simply by clicking the left mouse button at that time, and then make changes in the playnotes and try again.  When a track is muted, all displayed playnotes for that track will appear partially greyed-out as a reminder.

While in the Track Map Window, if you ask to edit a soundfile (Ctrl-E, or Edit Input File, from the Soundfile menu) the editor will open the soundfile which is currently listed in the soundfile textfield on the lower right of the window.

Visual editing in the trackmap window

Adding New Playnotes

You can add new playnotes to the mix simply by typing them in the playnote entry field and hitting <return>.  If the "autoReload" option is set, the playnote list will automatically reload each time you add a new note. Otherwise, you will need to hit  reload playnotes or reload everything. The default program state assumes that what you are entering in this field is a new playnote, unless you have previously selected a playnote (and one is highlighted in red). This sets the state to modify. The state will be reset to the default add when you hit reload playnotes or reload everything.

A potential source of confusion exists when you have used the offset and/or the addoffset feature in the playnote editor. Remember that when you enter new playnotes the starting time will be incremented to whatever the cumulative offset is at that point for the mix, and the displayed playnotes will reflect this.

Dragging Sounds into the Window

A fast way to add and audition new input soundfiles as playnotes is to drag soundfile icons directly into the track map window.  Doing this does three things:

  1. It appends the soundfiles to the soundfile table.  If any of the sounds was already present, it adds a second copy of each to the end of the list.
  2. A default playnote command for each soundfile is added to the playnote list.  The snd tag is set to the new sound's number, the track tag is set to the track over which you dropped the sound icon, and all other fields are left to their defaults.  If multiple sounds were dropped, the playnote commands are placed on the next highest track, sequentially (modulo the number of tracks).
  3. The driver reloads in order to add the new input soundfiles and display the playnotes.  If there is an error loading any of the soundfiles, you will be notified -- and you will be responsible for removing the offending file(s) from the soundfile table.

Editing Playnotes with the Mouse and/or Keys

Playnotes can be moved around with the mouse or the arrow keys. To move a playnote with the mouse, hold down the <shift> key and click on the playnote you want to move with the left mouse button. Note that the text and end-bars for this note are now displayed in red.  This indicates that this is the playnote selected for editing.  Now while holding the <shift> key down, drag the playnote with the mouse. You will see a white version of the soundfile move with the mouse. You can change both its start time and track number this way.  As you move the soundfile you will see the values for at= and track= change in the playnote editor below.  When you release the mouse button, the original image of the soundfile will disappear and the new one will assume its color. If the "autoReload" option is set (via resource or the Auto-Update track map command in the Options menu), the playnote list will automatically reload each time you release the mouse button, and the playnote will be unselected automatically.  If the option is not set, you can move around any number of soundfiles before hitting the reload playnotes or load everything button to put the changes into effect. In either case, if you move soundfiles to the right, later in time, you should use the load everything button.

The duration of playnotes can also be adjusted with the mouse.  To do this, hold down the <shift> key and click on the playnote with the right mouse button.  Dragging to the right and left will adjust the duration of the playnote.  As you do this, the value for dur= changes in the playnote editor below.  Note that you cannot drag between tracks using this command.  If the "autoReload" option is not set, you will have to reload playnotes after you are done (load everything would never be needed for this operation).

You can also move playnote by using the arrow keys, which will move them up or down one track at a time or back and forth in time, in 0.1 second increments. This feature merely requires that you have shift-clicked on the playnote on the playnote you wish to move with the left mouse button.  When you are done, hit <return>, or shift-left-click anywhere in the window to redraw the playnote in its new location.  Again, if the "autoReload" option is not set, you have to reload playnotes or load everything after you are done.

The gain of playnotes may be adjusted up and down with the keypad '+' and '-' keys or the mouse wheel (if you have one).  To use the keys, select a playnote using <shift>-leftmouse.  The '+' key will increase the gain by 1 dB;  if the <shift> key is down as well, the gain will increase by 3 dB.  The '-' key will reduce the gain in the same fashion.  To use the wheel, simply scroll the wheel up and down.  As you do this, you will see the values for gain= change in the playnote editor below.  Note that the relative colors of the various playnotes will also change to reflect the new gain relationships.  Note:  You must reload playnotes after altering gains to hear the effect -- these do not auto-reload.

Playnotes can be copied and pasted (one at a time) by selecting them and using the Copy and Paste commands from the Edit menu or the keyboard equivalent.  When pasting, the new playnote will appear in the next higher track (subject to wrapping), and its text will be visible in the playnote editor.  Paste will not check for overlaps with existing playnotes, so you will need to do this after the paste.

Playnotes may be deleted by hitting the <delete> or <backspace> key after selecting them.  The playnote entries don't actually go away;  a comment is placed before the playnote line in the score.  This allows you to undelete the entry at some future time, or clean them up (remove completely) on your own, later.  The playnote list is always updated after a delete.

Controlling track playback from the track map window

Tracks can be muted and soloed directly from the track map window by using a combination of the middle mouse button and various keyboard letters while the mouse is over a track.  Use the z key to mute tracks, the x key to unmute tracks, the s key to solo tracks, and the u key to unsolo tracks. You can drag the mouse up and down to select groups of tracks. When a track is muted, the line under that track will turn blue, and all playnotes on that track will appear partially grayed-out.When soloed, the line under that track will turn yellow, and playnotes on all unsoloed tracks with appear partially grayed-out. You can mute and unmute all tracks with Ctrl+t, and unsolo all tracks with Ctrl+U.


Various Buttons


  1. Load Everything.
    Mashing this button does the following: It opens and stats all the soundfiles listed, it reads in the playnotes, it reads the timescale, the number of tracks, and the state of the individual input and output tracks. It also allocates memory. When it is blue it indicates that no relevant information is in memory, that memory is not allocated, and that nothing will happen. Since qrt uses a lot of virtual memory, miniaturizing the app in this unloaded state makes it possible to have a very large number of these apps running simultaneously. (See the section on Memory Use).
  2. Kill everything.
    Mashing this guy will simply kill the current driver and stop everything that is going on. It resets the app to a zero state, and releases virtual memory. It is useful to hit this when things get confusing or out of hand.
  3. Reload Playnotes.
    This button assumes that the driver is already running, and it will simply read in either the entire contents of the playnote editor, or a selection you have made with the mouse. This is useful if you want to add a note or alter a note. You have to be careful about allocation here, however, since a track can only play one note at a time you may wipe out something that was already there. (This is often what you want to do.) When things get too complicated it is usually best just to restart the driver.
  4. Play.
    This will play the currently loaded mix, using the times given in the play from, play to forms. The button is inactive unless the 'load everything' button has been hit.
  5. Stop.
    This will stop the currently playing mix, but will not kill the driver. Sometimes it takes a moment or two to kill the playing process.  This button is inactive unless a mix playback is in progress (or is paused).
  6. Pause.
    This will pause the currently playing mix. This button is inactive unless a mix playback is in progress.


Other Controls



Order of Operations.


If you make any changes in the names, conditions, or numbers of soundfiles, or the timescale or maximum number of tracks, you will have to restart the driver (kill everything, load everything). Most other changes, such as altering the times of a mix in the track control window, some changes in the playnote editor, turning soundfiles off and on in the soundfile table, making any changes in the tracks window, can be done without restarting the driver.


qrt scripts


The entire state of a mix can be saved to a simple ascii file with file type .qrt or .rt. This is done from the File menu, and if it is a new mix, you will be prompted for a filename. Similarly, you can restore a mix by starting qrt with the script specified in the command line, or by opening qrt and then loading in the script from the files menu.


Saving Mixes


When you finally want to save a mix to disk, before hitting the play button, choose an option from the Play Mix To menu in the Main Window. If you choose one of the three file options, qrt will prompt you for a soundfile path.  Now hit the play button.  What will be written to disk is exactly what you would have heard had you hit the play button alone.  As the mix proceeds, you will be updated on its progress via a dialog panel, and you have the option of interrupting the mix at any point.  The output option resets after each play command, so you will have to repeat the above steps to rewrite the mix to disk.

It's up to you to make sure you have enough disk space.


Errors in Scorefiles and Playnote Lists


Qrt errors fall into one of three classes:  setup errors, soundfile errors and score errors.  Setup errors involve parameters that are parsed prior to the playnote list, and include things like track count, track gains and volumes, and timescale settings.  Soundfile errors include nonexistent or malformed soundfile path names and invalid or unsupported sound formats.  Score errors comprise the majority of the possible errors, and include invalid command strings, invalid parameter values, malformed parameter lists (e.g., odd number of parameters passed to amp()), and any other place where the parser gets confused.

No error checking is done until you first attempt to load everything, at which time qrt will report all three types of errors.  Opening and closing qrt scorefiles without loading does not invoke the parser.  If there is a setup error during loading, qrt will report it in the status window on the main panel, and via a pop-up alert if you are currently viewing any other panel.

If setup succeeds, but there is an error involving one or more of the soundfiles, qrt will report it in the same manner, with these additional features:  A pop-up with an OK/CANCEL choice will appear, and the offending soundfile's row will be selected.  This should make it easier to locate the problem file.  If you choose not to cancel upon receiving the pop-up, qrt will continue to parse the soundfile list until it either reaches the end or hits another error -- but it will not continue beyond that point.  If you choose cancel, the parse will stop at that point.

If setup and soundfile loading both succeed, but there is an error in your score, in addition to the pop-up and status display, the offending line will be highlighted in the playnote editor.  If the driver was already loaded and the error occurred during the score parse, you can just hit reload playnotesafter fixing the error.  You will at least need to unselect the highlighted line before reloading or else you will only load that one line!.

With the exception of the soundfile errors, qrt stops parsing at the first error it encounters.  You will have to reload and fix later errors one at a time.


Editing Soundfiles and Playnotes


To edit an input soundfile, right click anywhere on that soundfile's line in the soundfile table, except over its gain, and choose edit with external editor from the context menu. The sound editor program specified by the soundEditor resource will be invoked on the soundfile, if the program is installed on your machine.  Otherwise you will be alerted that it can't find it.  Under Linux, the current default is Douglas Scott's "mxv" program.

You can also edit the sound output of a playnote, as modified by its parameters. To do this you need to select a playnote in the Track Map Window by shift-leftmouse clicking on it. The playnote will then appear in the form at the bottom left of the Track Map Window. Then, Ctrl-K will write that playnote's sound in /tmp, and the sound editor program will open that file. When you are done you will be prompted to see whether or not you want to save the soundfiles in /tmp. Note that any changes made to the playnote soundfile with the sound editor will have no effect on the resulting mix.


Memory Use


Qrt works by dividing time into ticks, as specified in the timescale window. Each tick contains information about what is going on at that track, at that time. For each track there are 200000 ticks allocated for each cell of 10 parameters. Normally only a small number of these cells are used, but when the memory is allocated the operating system checks to see if that much virtual memory is available. So, for 12 tracks, you would have to have 12*36*200000 = ~87 megabytes of virtual memory. In the (unlikely) event that you had all 12 tracks going for all 200000 ticks and were setting all parameters all the time you *might* start to use up your swap file. (I've never seen this happen, but it's possible). The following are recommendations regarding use: First, when the 'load everything' button is in its yellow state, no virtual memory is allocated. This means that you can have lots of different rt jobs running at the same time, as long as the sum of the requested virtual memory doesn't exceed what you have available. Second, use only as many tracks as you need, and specify the limit in the tracks window. This way less virtual memory will be requested. Finally, if you are going to 'minimize' an rt job, be sure to 'kill everything' before you do. This way it will take up only a few MB of available memory.


Performance


Look ahead buffers:. There are two internal buffers which are used. One is in the driver, and the other is in the audio hardware. The driver buffer is fixed, but the size of the audio buffers can be adjusted to be between one and six 32k buffers by using the slider on the track window. The effect of decreasing the number of these buffers is that changes made by moving the sliders for the individual tracks and the output tracks will take effect more quickly, as will the stop and pause buttons. The negative effect is that there may be glitches since the audio hardware may run out of data. For complicated mixes it is best to use a larger number of buffers. You don't need to restart the driver to reset the buffers, but they will not take effect during a play.


A Quick Tutorial


You have three soundfiles you want to work with. Let's call them talk, whistle and knock.

  1. Enter them, in this order, in the soundfile table.
    talk
    is a long soundfile and you want to use selected parts of it. whistle is the sound of someone whistling which you want to intersperse here and there, and knock is a simple annoying knocking sound.
  2. You might have the following list in the playnote editor
    playnote(snd=1,track=1,amp(0,1,4,1,5,0), end=10) //give me 10 seconds of talk fading out at the end
    playnote(snd=2,track=2,amp(0,0,1,1,2,0), skip=2,end=5,transp=-1,at=5)
    // give me times 2 through 5 of the whistle, down 1 semitone starting at time5

    playnote(snd=3,track=3,at=3,pan=-0.3)
    playnote(snd=3,track=4,at=3.2,pan=.6)
    playnote(snd=3,track=3,at=3.4)  // several knocks, assuming that the knock is less than .4 seconds long
  3. Then press load everything followed by play, and listen. You notice that the balance and envelopes are all wrong so you open up the track control window and adjust the gains individually, listening to the sounds individually.
  4. You decide that the transposition level for the whistling is all wrong so you change the transp=-1 to transp=-2. Then select this line and press the reload playnotes button. Press play and listen again
  5. You then decide that the whistling comes in too soon, so you adjust its at=5 to say at=6, select, load and play. Now you notice however, that the note still starts at time 5 and then starts again at time 6. In other words you haven't wiped out the first reference to it. The only thing to do now is to restart the driver by pressing the load everything button..
  6. You want to listen to the section from time 3 on now, so you type 3 in the play from form in the control window.
  7. You decide it is good enough for your recording company so you write the mix to disk and go to bed happy. 

Tooltips


Most of the visible widgets in qrt have tooltip text.  This will display as a text popup when the mouse hovers over a widget.  This can be turned on and off from the Help menu.


Bugs



Customizing


As of April 2005, QT's internal customization via resource system is nonexistent.  A small number of features and settings are currently supported via a qrt initialization file, which is called .qrtrc under Linux, .qrtinit under MacOSX, and qrt.ini under Windows (not supported yet):

Widget Resources

 Using an ungainly customized system I created, attributes for font, foreground color, and background color may be set of any of the below-listed widgets using the X resource format.  For example, to set the _outputGainLabel foreground color to blue, add a line to your qrt initialization file as follows:

_outputGainLable.fg:   Blue

To set the background for all push buttons white, you can specify the widget type instead:

QPushButton.fg:   White

In the lists which follow, the name in bold is the class name;  the _underbarName is the name of the specific widget.  Please note that I will not guarantee that this set of widgets and/or the widget names will remain consistant or complete over the course of development.  I will do my best to keep this list updated.

QCheckBox _autoScrollCheckBox,  _decibelButton
QComboBox _outputChooserComboBox
QLabel _L_Label,  _lookAheadBuffersLLabel,  _muteLabel,  _outputChooserLabel, _outputGainLabel, _pixmapLabel1, _playFromLabel, _playFromLabel2, _playFromLabel3, _playToLabel, _playToLabel2, _playToLabel3, _QRTLabel1, _R_Label, _soloLabel, _soundfileGainLabel, _timeScaleLabel, _trackControlFormLabel, _tracksLabel
QLCDNumber _currentTime, _currentTime2, _currentTime3, _currentTime4
QLineEdit _endTimeEdit _endTimeEdit2, _endTimeEdit3, _lapTime2, _leftLevel1, _leftLevel10, _leftLevel11, _leftLevel12, _leftLevel2, _leftLevel3, _leftLevel4, _leftLevel5, _leftLevel6, _leftLevel7, _leftLevel8, _leftLevel9, _leftOutputLevel, _leftPeak, _leftPeakHold, _rightLevel1, _rightLevel10, _rightLevel11, _rightLevel12, _rightLevel2, _rightLevel3, _rightLevel4, _rightLevel5, _rightLevel6, _rightLevel7, _rightLevel8, _rightLevel9, _rightOutputLevel, _rightPeak, _rightPeakHold, _selectedPlaynoteEdit, _selectedPlaynoteSoundfile, _soundfileGain, _startTimeEdit, _startTimeEdit2, _startTimeEdit3, _startTimeEdit4, _timeScaleEdit
QMenuBar _menubar
QPopupMenu _controlsMenu, _editMenu, _fileMenu, _helpMenu, _optionsMenu, _playnotesMenu, _soundfilesMenu, _windowMenu,
QPushButton _killDriverButton, _killDriverButton2, _killDriverButton3, _killDriverButton4, _lapButton, _lapButton2, _loadDriverButton, _loadDriverButton2, _loadDriverButton3, _loadDriverButton4, _loadPlaynotesButton, _loadPlaynotesButton3, _loadPlaynotesButton4, _mainTrackMuteButton1, _muteButton1, _muteButton10, _muteButton11, _muteButton12, _muteButton2, _muteButton3, _muteButton4, _muteButton5, _muteButton6, _muteButton7, _muteButton8, _muteButton9, _pauseButton, _pauseButton2, _pauseButton3, _pauseButton4, _playButton, _playButton2, _playButton3, _playButton4, _playSelectedInputSoundfileButton, _playSelectedPlaynoteButton, _resetButton, _rewindButton, _stopButton, _stopButton2, _stopButton3, _stopButton4, _trackMuteButton1, _trackSoloButton1, _zoomInButton, _zoomOutButton
QRadioButton _checkPeakButton
QSlider _leftOutputSlider, _leftSlider1, _leftSlider10, _leftSlider11, _leftSlider12, _leftSlider2, _leftSlider3, _leftSlider4, _leftSlider5, _leftSlider6, _leftSlider7, _leftSlider8, _leftSlider9, _rightOutputSlider, _rightSlider1, _rightSlider10, _rightSlider11, _rightSlider12, _rightSlider2, _rightSlider3, _rightSlider4, _rightSlider5, _rightSlider6, _rightSlider7, _rightSlider8, _rightSlider9, _soundfileGainSlider
QSpinBox _lookAheadBuffersSpinBox, _trackCountSpinBox
QTable _soundfileTable
QTextEdit _playnoteEditor, _playnoteEditor2, _statusText


Acknowledgments


Thanks go profusely to Paul Lansky for creating the original version of this program on the NeXT platform, for his port to the SGI platform, his initial work porting Rt to Linux, and his advice while porting to QT and adding new features.  The following are Paul's original acknowledgments for his ports,   I keep them here because we all stand on the shoulders of our predecessors:

Thanks to David Jaffe for important additions to the NeXT port, which will also make it into this port, eventually. Peter Velikonja did the major work in de-NeXTifying the sound driver so that it would work without the SoundKit. To Doug Scott for simplifying the use of the SGI Audio Library for me. Thanks to Bill Schottstaedt for helping to grok aiff files. And, most of all to Kent Dickey, whose class project in Cos/Mus 325, the driver for this app, has helped out so many people since that time. (I should have given you an A+)

Paul Lansky 1/5/97

Douglas Scott
February, 2005