QV(1) — USER COMMANDS
NAME
qv - quick video viewer for VEX
SYNOPSIS
qv [-toolkitoption ...] [player]
DESCRIPTION
Qv is an application under development. It currently provides control over VEX-compatible devices, display of video in a separate window, and capture of video frames. By default, the first player known by VEX is used.
The possible qv windows are the controls window (name: qv, class: Qv), the video window (name: qvideo, class: Qvideo, title is the name of the video player), the capture window (name: qvcapture, class: Capture), and the help window (name: qvHelp, class: Help). If there are no video inputs, only the controls and help windows will be available.
The controls window has three menus: File, Commands, and Help, and has a controls area. From the File menu, you may quit the application. From the Commands menu, you may turn the on-screen index function on and off, capture the video screen, or clear the memo buttons. From the Help menu, you can get help on using the application.
The controls area consists of a shuttle, a set of control buttons, and a set of memory buttons. The shuttle consists of a status indicator, which gives the speed and direction of the video device, a slider for setting the speed, and a pair of buttons for incrementing and decrementing the speed in single steps. The control buttons allow quick access to the normal and fast forward and reverse speeds, as well as single frame forward and reverse. The memory buttons allow you to save favorite running speeds and get back to them quickly. Pressing a button marked "Memo Set" saves the current speed in that button (the value can be cleared using the Commands menu). The "Previous" button recalls the previously-used speed.
The video window displays the video. On this window, the character q quits, f plays, F plays fast, r plays in reverse, R plays in reverse fast, p pauses, h brings up the help screen, c captures the screen, and i toggles the on-screen index. These mappings can be modified by setting the Qvideo∗translations resource and using the actions documented later in the manual.
The capture window displays a copy of the captured image and a menu for saving the image. By default, the image is show 1/4 size, but this can be changed by setting the resource qvcapture∗reduction to the denominator (e.g., a value of 2 displays 1/2 size). The denominator must be between 1 and 8, inclusive. The reduced image is not resizable at this time. The captured image or the reduced image may be saved as a PPM (portable Pixmap) image or as an XWD image.
The help window displays a help message. At this time, only general help is available. The File menu provides a function to dismiss the help window.
IMAGE CAPTURE
When an image is captured, the player is paused, the image is grabbed, and the capture window is displayed with the reduced image in it.
You do not have to pause the player manually, though this is recommended to get the best possible image (some frames contain a lot of motion or interlace blurring). Some devices and media (such as the Sony LDP-1550 using non-CAV discs) do not allow screen pause, and thus do not work well with capture (though the results can be very interesting).
It is very important to note that image capture is done using a very simplistic mechanism which copies the area of the screen containing the video widow. If there are any windows overlapping the video area, the overlapping contents of these windows will be captured instead of the video under them. Because of this, it is recommended that the captured image reduction factor be at least 4 (this will make the window small enough to keep it out of the way for future captures).
Image capture can take a few seconds, so before capture begins, the bell is rung, and afterwards it is rung twice.
Once the image is captured, a reduced version is displayed. You may save either the full-sized version or the reduced version. If you need to resize the image, it is recommended that you save the full-sized image and use a tool like xv(1) to do the resize.
The image may be saved in either PPM or XWD format. PPM format takes longer to save and takes more disk space, since the data is saved as separate red, green, and blue values. The advantage to PPM is that it can be quickly dithered and displayed with the xv(1) program on an 8-bit display. XWD is the standard X Window Dump format and can be displayed by the xwud(1) program. This provides the best results on a screen with the same or larger depth as the screen where the capture was made, but takes too long to display on 8-bit or shallower screens.
OPTIONS
Qv accepts all of the standard X Toolkit command line options along with the additional options listed below:
−help This option indicates that a brief summary of the allowed options should be printed on the standard error.
RESOURCES
Qv has been designed to be as user-configurable and localizable as possible. The widget resources are all listed in the app-defaults file for the class Qv. Application-specific resources are listed below. Classes are given in parentheses.
The control window (name: qv, class Qv) has the following resources:
player (Player)
This is the name of the player to use. The default is the first configured VEX player.
stopString (StopString)
This is the string to use to indicate that the player is stopped in the shuttle status indicator. The default is "Stop".
stopColor (StopColor)
This is the color of the "stopped" status message. The default is red.
forwardString (ForwardString)
This is the string to use to indicate that the player is going forward in the shuttle status indicator. The default is "Forward".
cueString (CueString)
This is the string to use to indicate that the player is going fast forward in the shuttle status indicator. The default is "Cue".
forwardFracString (ForwardFracString)
This is the string to place after the speed when the player is going forward at a speed other than the Forward and Cue speeds. The default is "Forward"
forwardColor (ForwardColor)
This is the color of all status messages when the player is going forward, including fractional and high speeds. The default is green.
reverseString (ReverseString)
This is the string to use to indicate that the player is going backwards in the shuttle status indicator. The default is "Reverse".
reviewString (ReviewString)
This is the string to use to indicate that the player is going fast backwards in the shuttle status indicator. The default is "Review".
backFracString (BackFracString)
This is the string to place after the speed when the player is going backward at a speed other than the Reverse and Review speeds. The default is "Backward"
reverseColor (ReverseColor)
This is the color of all status messages when the player is going backwards, including fractional and high speeds. The default is yellow.
memoLabel (MemoLabel)
This is the label string for the "Memo Set" labels when they are cleared. This resource should match the memoryButtons∗labelString resource unless otherwise required. The default is "Memo Set".
bellVolume (BellVolume)
This is the volume of the bell sound played once when capture is initiated and twice when capture has completed. The number should be from -100 (off) to 100 (loud), with 0 being normal server volume. The default is 0.
The capture window (name: qvcapture, class Capture) has the following resources:
reduction (Reduction)
This is the amount that the captured image is reduced by for display (the captured image is not resizable at this time). This may be an integer from 1 to 8. The default is 4 (image displayed at 1/4 size).
xwdName (XwdName)
This is the name used as the title of the saved image when saved in XWD format. The default is "video image".
defaultBigPPM (DefaultName)
This is the name suggested as the name of the file to be saved to when the full-sized image is saved in PPM format. The default is "video.ppm".
defaultBigXWD (DefaultName)
This is the name suggested as the name of the file to be saved to when the full-sized image is saved in XWD format. The default is "video.xwd".
defaultSmallPPM (DefaultName)
This is the name suggested as the name of the file to be saved to when the reduced image is saved in PPM format. The default is "video.small.ppm".
defaultSmallXWD (DefaultName)
This is the name suggested as the name of the file to be saved to when the reduced image is saved in XWD format. The default is "video.small.xwd".
The help window (name: qvHelp, class Help) has the following resources:
helpDir (HelpDir)
This is the directory name for the help data. The default is /usr/lib/X11/qv/help.
helpError (HelpError)
This is the string to display when there is no help available on the requested subject. The default is "No help available".
ACTIONS
The following actions are registered for the control window:
quit Exits the program.
forward Sets the player speed to Forward.
reverse Sets the player speed to Reverse.
cue Sets the player speed to Cue (fast forward).
review Sets the player speed to Review (fast reverse).
pause Stops the player.
stop Stops the player.
jogF Stops the player and moves one frame forward.
jogR Stops the player and moves one frame backward.
jog(n) Stops the player and moves n frames. A negative n goes backwards.
speedAbs(n)
Sets the speed to the value of speed slot n. Speed slots are defined for each device, making this action fairly useless unless you experiment.
speedRel(n)
Sets the speed to the value of the speed slot that is n away from the current slot. A value of 1 for n will act like pressing the right shuttle button.
previous
This goes back to the previous speed value.
memo(n)
This acts the same as pressing memo button n (from 1 to 3). If the memo button is not set, it is set to the current speed. If it is set, the speed of the player is set to that speed.
memoSet(n)
Set the speed of button n to the current speed.
memoClear(n)
Clears memo button n.
index This toggles the on-screen index. Note that this index is device-specific.
capture This captures the current image. See the "IMAGE CAPTURE" section for details.
help This displays the help message window.
The capture and help screens also have the following action:
dismiss Dismiss the window.
SEE ALSO
AUTHOR
David Elliott, Sony Microsystems Corp.
April 13, 2022 — Last change: