What is baudline?
Mystery Signal
zoom control
The zoom control is a handy little window that allows the quick changing of the spectrogram and the waveform time axis zoom factors.  Some might find this window more convenient than the Alt+arrow keyboard or Alt+scroll wheel shortcuts. 

The dual zoom lock forces the spectrogram and the waveform zoom factors to be locked together and track each other.  That means if you zoom one window the other window zooms too. 

The fractional zooming option allows zooming into the spectrogram window deeper than is defined in the input scroll control window.  Fractional zooming is a very CPU intensive activity and it is very useful if you are low on allocated memory buffers, doing long duration data collection, or just want to zoom way in to the slice sample level.  Most users will want to keep this feature enabled.

These two sliders are only operational when baudline is in the pause or play modes.  Note that the spectrogram and waveform windows can be equivalently zoomed by using the Alt+arrow keys or the Alt+scroll wheel shortcuts.

The stats window contains baudline's internal performance statistics.  Some fields are accumulated counts while others are measured values or internal equilibrium variables.  This window could be useful for diagnosing the cause of audio driver or choppy frame rate problems.  The transforms/sec or video FPS fields also could be used as a rough benchmark measurements.

transform count
This is the number of transforms (FFT's) that baudline has calculated since program startup.

This is the number of transforms per second that baudline is currently processing.  This includes pre-processing the waveform slice data, windowing it, FFT'ing it, turning it into log (dB) magnitude or phase space, and any screen or internal rendering of the graphical data.  As a benchmark reference, when iconified and set to a 2048 point FFT size, baudline can render 1300 transforms per seconds with a 450 MHz Pentium 2 and around 2000 transforms per second on a 650 MHz Pentium 3.

video FPS
This is how many video frames per second (FPS) that baudline is currently sustaining.  This is actually a function of many things.  FFT size, window dimensions, window visibility, backing store, number of channels active, CPU and video card performance and load all contribute heavily to this number.  Full screen 1280x1024, mono input with the startup -reset defaults, a 450 MHz Pentium II with a fast graphics card should be able to sustain a 70+ FPS rate.  For high baudline frame rates note that the performance of the video card's 2D hardware acceleration is as important as having a fast CPU. 

jump step
This parameter controls how jumpy the scrolling is which has a direct effect on the frame rate (FPS).  Baudline dynamically adjusts this number for maximum performance so it is normal for it bounce around.  The jump step parameter can be manually adjusted ±1 by pressing the widget buttons, the up/down arrow keys, and the mouse scroll wheel.  Holding down the Alt key while performing the increment action will change the jump step value by ±5 units.

This is a count of how many times the audio driver has been stalled.  Baudline automatically detects and restarts a stalled audio driver.  But still, stalling is bad as it causes gaps in the input or output stream.  A working system should not stall even under heavy load.  Stalls are a sign of major problems in the audio driver. 

potential drops
Also known as xruns or overruns.  This count is the number of instances that baudline has detected that the input or output stream has been interrupted.  This could have resulted in an audible gap or click.  The clear button clears this count to zero just like the trip odometer button in your automobile.  Dropping is caused by the CPU being too slow to handle the current load smoothly.  So in normal usage there should be no potential drops; if there is, reduce the overlap amount in the scroll control window

Moving X-Windows around in opaque mode on a Linux box is a sure way to cause potential drops.  This is because dragging an opaque window puts instantaneous demands on the CPU and video bandwidth.  In Linux the X Server runs at root priority, so the X task hogs the resources, something has to break, and results in potential drops as the slip point.  Note that if you run baudline as root, which is not recommended, then baudline schedules itself as a real-time task (SCHED_RR).  Running as a real-time task improves the smoothness of baudline's scrolling and it reduces the susceptibility to potential drops


The about window displays baudline's version number, a brief description, a hyper link to the baudline web page, and the distribution notice.

mouse buttons

button window action  
1st spectrogram, waveform  crosshairs, selects or locks/unlocks cursor if clicked without motion

spectrum, average click and hold crosshairs, shift and drag delta measurement box 

histogram click and hold crosshairs

2nd histogram, average pastes selected data

spectrogram, spectrum pops up harmonic helper bars

waveform crosshairs then Shift key pops up periodic helper bars

3rd all pops up main menu

wheel spin all scrolls up and down or left and right if <Shift> is held
wheel tilt all scrolls left and right
Alt + wheel  all zoom in/out on vertical or horizontal axis if <Shift> is held 
Shift + button1  spectrogram, waveform  start or end selection repositioning

Mouse Wheel
Zooming, scrolling, sliding, and spinning.  Basically any baudline action that can be accomplished with the arrow keys can also be done with the mouse wheel.  The Up and Down arrow keys translate directly to the mouse wheel rotation motion.  Holding the Shift key while spinning the mouse wheel performs a 90 degree flip and is equivalent to the Left and Right arrow keys.  Mice with a tilting wheel are also supported and this action translates to the Left and Right arrow keys.  The -modifier also works with the mouse wheel.

Horizontal and vertical zooming can be performed in all of baudline's main windows with the Alt+wheel and the Shift+Alt+wheel combination. 

The mouse wheel can be used on all of baudline's sliding widgets.  It also works in the File Selection window and with the Tone Generator's several Hz selection boxes.

keyboard hotkeys

key action  
<Pause> toggle between Record, Pause, and Play modes
<Home> jump to top of document
<End> jump to bottom of document
<Page Up> move up a page
<Page Down> move down a page
<arrow keys> directional navigation or zoom if <Alt> hotkey is held
<F# keys> selection banks or Average banks
<PrintScrn> capture screenshot to PNG file
<Delete> clear Average or clear Histogram capture buffer
<Space> toggle on/off Average collecting
Alt + R toggle on/off rulers
Alt + W close window
Alt + O open file
Alt + I file info window
Alt + A select all
Alt + S save selection
Alt + P play selection
Alt + arrow zoom in that direction
Shift horizontal modifier key (wheel or Home and Page keys) 
, halve playback speed
. double playback speed
/ toggle playback direction

Many of the above hotkeys are generic and they work in most of baudline's windows.  Take note that most of the "extra" keys on the standard 104 keyboard are mapped to special features.  Look for the hot key short cuts in all of the popup menus.  See the example on the right. 

The default command modifier is the key key on On Linux, FreeBSD, and Solaris the default command modifier is the key.  On Mac OS X the default default command modifier is the key which is the Apple Command key.  The -modifier command line option can be used to change this command key.

The Shift modifier key flips the directional control from vertical to horizontal for several actions.  Doing Shift+scroll_wheel or Shift+Alt+scroll_wheel operates on the horizontal axis instead of the vertical.  The same is true for Shift+Home, Shift+End, Shift+Page_Up, and Shift+Page_Down.

Note that navigating the time axis (arrow keys) works as expected in the Pause mode.  In the Play mode it is like Fast Forward/Reverse scanning, and in the Record mode it is not possible.

Print Screen
Capture a screenshot of the display window to a PNG file.  Press the <PrintScrn> key in any of the display windows (main spectrogram, average, histogram, or waveform).  When the mouse wait cursor returns to its normal arrow shape the operation is complete.  The newly created image PNG file will be named one of the following:
  • baudline_spectro.png
  • baudline_average.png
  • baudline_histogram.png
  • baudline_waveform.png
If a -session is being used then that name will replace "baudline" in the above file names.  Note that some window managers map the <PrintScrn> key to their own capture function, this will have to be disabled if you want to use baudline's image capture feature.

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