MPlay's User Interface
MPlay's main user interface is arranged in collapsable bars around the
outside of the image. Each bar can be collapsed, shown or hidden,
depending on the profile layout (see Profile Manager for details on
profiles). A bar may be collapsed by clicking the small bevelled
rectangle at the left or top of the bar. If a bar is already collapsed,
it will appear as a thin horizontal or vertical bar. Clicking the bar
will show it. If a bar is hidden, it will not appear on the UI at all -
you will need to use the Ctrl+RMB menu (over the viewport) and toggle
on the bar (you can do this with collapsed or exposed bars, as well).
Menu
Bar
Main Bar
Diff Bar
View Bar
Display Bar
Inspect Bar
Control Bar
Playbar
Each bar generally contains similar types of controls.
- Menu Bar
- Contains the MPlay menus, the half/double window size controls, and
the rendering controls (if this mplay is listening for renders or
flipbooks).
- Main Bar
- This bar controls the viewer mode, displayed plane and manages the
viewports.
- Diff Bar
- This bar controls the options for diffing (comparing) 2 images
together.
- View Bar
- This bar controls zooming and homing.
- Display
Bar - This bar controls the Display Options and displayed
items.
- Inspect
Bar - This bar shows pixel inspection information.
- Control
Bar - This bar has additional controls for manipulating the
display of the image.
- Playbar
- This bar contains all UI relating to playing frames.
Each bar's components are explored in detail below, from left to right
for horizontal bars, and top to bottom for veritcal bars.
Menu Bar

File Menu
- Open - Opens a new
sequence of images, and removes all existing sequences.
- Merge - Opens a new
sequence of images, leaving existing sequences.
- Save Current Frame -
Saves the current frame of the current viewport's sequence ( the
current viewport is outlined in green).
- Save Current Sequence -
Saves all, or a part of, the sequence in the current viewport.
- Save Preview - Saves the
current frame of the current viewport's sequence, exactly as it appears
in the viewport, with all image transformations applied. This includes:
- Color corrections, such as gamma, brightness, LUTs and contrast
- Color Component
- Cropped area (done with Shift+LMB drag)
- Image composited over the background image, if any
- Any comparisons done with the diff bar (ie, a Horizontal Wipe).
- Any conversions or emulations (like conversions to 8bit).
- Load Audio - Loads audio
through the Audio Panel dialog. This dialog also sets the volume, audio
synch and sustain options.
- Unload Audio - Turns off
any loaded audio file.
- Sequence List - Pops up
the Sequence List manager, where you can view and manipulate the
various image sequences loaded into mplay.
- Insert Sequence Before -
Inserts a new image sequence before the sequence in the current
viewport. The existing sequence will not be moved in time - the start
of the sequence will be moved to accomodate the length of the new
sequence. This action corresponds to the prependseq script command.
- Append Sequence - Appends
a new image sequence after the sequence in the current viewport. The
existing sequence will be extended by the length of the new sequence.
This action corresponds to the appendseq script command.
- Clear Cache - Clears out
the image cache, freeing up memory.
- Cache All Images - Caches
all images in memory, and increases the cache size to fit them all, if
necessary.
- New Viewer - Spawns a new
MPlay viewer, which can be set up independently of this viewer. The
playbars are always linked, however.
- Quit - Exit MPlay.
Options Menu
- Settings - Launch the
Settings dialog, where you can set such things as the Frame Range,
Missing Frames options, and Cineon parameters.
- Profiles - Launch the
Profile Manager dialog, where you can set and customize the various
mplay profiles.
- Textport - Show the
textport. MPlay has a smaller command
set than Houdini, as most Houdini commands don't apply.
- Help Browser - Pops up a
HTML Help Browser window (similar to the one you're likely reading).
- Double Buffer - Toggles double buffer mode. By default, double
buffer is off, since single buffer offers much faster playback. If you
encounter significant image "tearing" or other horizontal playback
artifacts, try turning this on.
- Hide Extra UI - Toggles
all UI except the playbar. Useful for quickly hiding all the mplay
gadgets.
- Help Tags - Toggles the
Popup UI Help Tags, which you will see if you hold the mouse over most
UI gadgets in MPlay.
Images Menu
This menu lists all the image sequences
currently loaded into mplay. The sequence in the current viewport is
highlighted. Selecting another image sequence will change the sequence
displayed by the current viewport.
Half Window Size (icon button)
Halves the MPlay window size (if
possible).
Double Window Size (icon button)
Doubles the MPlay window size, up to
the screen resolution.
(the following buttons only appear if mplay is listening for renders or
flipbooks)
Start New Sequence (icon button)
The next image received will go into a
new sequence. All subsequent images will be appended to that sequence.
Kill Renders (icon button)
Stops all active renders and terminates
the render process(es).
Disconnect (icon button)
Stops listening to renders. The next
image rendered to 'ip' will start a new MPlay process.
Main Bar

Viewer Mode Selection
(icon menu)
Selects the main viewing mode of this
MPlay window.
- Image (default) - View images as normal, 2D pictures.
- TimeLine - View sequences along a timeline graph to look at
timing.
- Graph - Displays a variety of different graphs of the images,
which are useful for image analysis.
Display Plane Menu (menu)
Selects the current plane to display.
The planes listed are a union of all planes in all sequences. Not all
sequences may have the plane selected.
Image Proxy Level (menu)
Selects the proxy level of the
image. This changes the image resolution, not the zoom (viewing)
level.
Viewport Layout (menu)
Sets the viewport layout, which is
useful for viewing more than one sequence simultaneously.
Frame Back (icon button)
Moves the playbar 1 frame back.
Frame Forward (icon button)
Moves the playbar 1 frame forward.
Adapt Frame Range (icon button)
Sets the playbar's frame range to the
frame range of the sequence in the current viewport.
Zoom Current Viewport (icon
button)
If more than one viewport is displayed,
this maximizes the current viewport to fill the viewport area. Toggling
this button off will restore the split viewport view.
Apply Changes to All Viewports
(icon button)
If on, changes to display options,
color controls, display plane selection and homing will affect all
viewports. If off, only the current viewport will be affected by these
changes.
Link Scolling to All Viewports
(icon button)
If on, scrolling or zooming in
one viewport will scroll or zoom to the same location in all other
viewports.
Diff Bar

Diff Sequence Menu (icon menu)
Selects the sequence to diff the
current sequence against. The diff sequence can also be selected in the
Sequence Manager.
Diff Mode (icon menu)
Selects the image comparison method (C
is the current sequence, D is the diff sequence):
- Diff - Absolute
difference between C & D. |C-D|
- Subtract - Subtracts D
from C (C-D)
- Horizontal Wipe - C on
left, D on right
- Vertical Wipe - C on
bottom, D on top
- Blend - Linear blend
between C (zero) and D (one).
- Highlight Differences -
Colors the pixel if the difference between the images is greater than
the threshold value (|C-D|>thresh). As the threshold value goes up,
the image will normally show fewer differences (only the more
significant ones). A value of 0.01 will normally eliminate jitter noise.
Diff Amount / Highlight Threshold
(float field and slider)
For horizontal wipe, vertical wipe and
blend, this represents the amount to blend C with D. For highlight
differences, this is the threshold value.
Frame Selection (icon menu)
Images can also be compared against
images at other frames. This is especially useful when you compare a
sequence against itself, but want to see the difference between frames.
- Current Frame
- Previous Frame
- Next Frame
- Frame Offset - Diff
against a frame some number of frames ahead or behind the current frame.
- Specific Frame - Diff
against a specific frame number.
Frame Number / Offset (integer
field)
For a frame selection of "Frame Offset"
or "Specific Frame", this specifies the frame offset or the specific
frame number.
View Bar

|
Zoom In
Zooms the view by 200%
(focusing in on the image)
Zoom Out
Expands the view by 200%
(showing more of the image)
Home
Adapts the image to its
home location. The image size and location depends on the following two
toggles.
Size Adapt
If on, and Exact Pixel
Size is off, this will fit the image to the viewport. If Exact Pixel
Size is on, it will attempt to center the image in the viewport. This
will be automatically switched off when you pan or zoom a viewport.
Exact Pixel Size
If on, the image will
appear at 100% zoom level, so that 1 pixel in the image corresponds to
1 screen pixel. If off, the zoom size can be any zoom level. This will
be automatically switched off when you zoom a viewport.
Clear Selection
If you have selected a
sub-region of the image by Shift+LMB dragging, this will clear the
selection and display the entire image.
Save Image
Saves the current frame of
the current viewport's sequence, similar to File->Save Current Frame.
Size Window To Image
Fits the MPlay
window around the image at 100% zoom. The MPlay window will not resize
to larger than the screen resolution, nor will it size to smaller than
its minimum size.
|
Display Bar

|
Open/Close Display Options
Pops up the Display
Options dialog (or closes it if it is already opened).
Enable Viewport
Turns on the current
viewport. If on, the viewport will not display anything except black.
Show Labels
Toggles the Information
text at the top of each viewport.
Show Guides
Toggles the Image frame,
TimeLine guides or graph guides.
Show Preview
Toggles the image preview.
In Image and Graph views, this is a small overview of the image in the
lower right corner of the viewport. In the TimeLine, this shows the
image sequence progression on the bars at frame intervals.
Toggle Rulers
Toggles the rulers, which
show X/Y pixel information.
Toggle Transparency
Toggles image
transparency. This will only do anything if the image has an alpha
plane.
Toggle Background Image
Toggles the background
image. If transparency is on, or a sub-portion of the image is
selected, you will see the background image behind the main sequences'
images.
Open Magnify Window
Opens the Magnify window,
which shows inspection information, plus a highly zoomed area of the
image, based on the mouse location over the image in the viewport.
|
Inspect Bar
The exact information show in the inspect bar depends on the viewer.
However, regardless of viewer, the values displayed are always linked
to the mouse pointer, and will always retrieve the information from
under the pointer (if any exists).
2D Image Viewer

The inspect bar shows the pixel value of the pixel under the mouse. The
information shown is:
Values Raw Values
Hue/Sat/Lum Inspect LUT values
X,Y pixel location U,V pixel location
Values shows the 0-1 value of the color, per component. (0=black,
1=white). Values may be less than zero or greater than one.
The Raw values show the actual values stored in the format (for 8 bit,
this would be values between 0 and 255). This will not appear if the
format is floating point (since it's the same as Values in that case).
The Inspect LUT values only appear if an Inspect LUT was specified in
the command line or the Display Options "Correction" page. This shows
you the raw values run backwards through the LUT. This is useful for a
format like Cineon, where you may want to see the Cineon numbers in
addition to the raw linear values.
The location of the pixel is shown in X,Y values (0 - xres-1, 0 -
yres-1) and U, V values (0-1).
Timeline Viewer

The inspect bar shows you what frame you are over, and its name (in
case many unrelated files are loaded into 1 sequence). It also
displays the frame range and frame rate of the current sequence,
and the resolution of the current image.
Graph Viewer

The information shown depends on the graph mode being used. For
histograms, it displays the current value and that values frequency in
the image. For other graphs, it shows the X axis and Y axis values,
plus the number of times that X,Y pair has occurred. For example, in a
Hue vs. Saturation plot, it would show you the current Hue value, the
current Saturation value, and the number of times that Hue/Saturation
pair occurred.
Control Bar

The control bar for the 2D Image viewer consists mostly of color
correction controls, so that you can more closely examine areas of
color. The timeline and graph viewers have different control bars,
explained below.
2D Image Viewer
RGBA Component View
The component strip allows you to view
an image's individual components (R,G,B or A). The far left button
returns to normal viewing mode (RGB). The default hotkeys for
this strip are:
Show All Components |
~ |
Show Red |
1 |
Show Green |
2 |
Show Blue |
3 |
Show Alpha / Fourth |
4 |
Color Controls
The image's colors can be manipulated
in two ways. The first is by modifying the images brightness, contrast
and bright shift. The second (accessed by clicking the circular arrow
button) allows you to specify the lower (black) and upper (white) range
of the displayed image. For example, setting the black point to 0.4 and
the white point to 0.6 would show 0.4 and below as black, 0.6 and above
as white, and values in between the two in much higher contrast than
normal.
When a color correction value is set to something other than its
default, its icon will turn red to warn you that the image displayed is
modified from its original color. You can reset all the color
correction values to their defaults by pressing Shift+R (default hotkey).
Both color modes are a different way of setting the same color values,
so they are tied together. When you toggle to the other method, it will
already be setup with the equivalent values to the previous method.
- Brightness/Contrast Mode
- Brightness (icon button
& float field) - Sets the brightness value (default 1). Clicking
the icon resets the value to 1.
- Contrast (icon button
& float field) - Sets the contrast value (default 1). Clicking the
icon resets the value to 1.
- Shift (icon button
& float field) - Sets the bright shift value (default 0). Clicking
the icon resets the value to 0.
- Black/White point Mode
- Black Point (icon
button & float field) - Sets the black point of the image (default
0). Clicking the icon resets the value to 0.
- White Point (icon
button & float field) - Sets the white point of the image (default
1). Clicking the icon resets the value to 1.
Gamma Control (icon button
& float field)
Changes the gamma of the displayed
image. Clicking the icon resets the gamma to the default gamma setting
(defined in the Display Options, Correction page) which is normally 1.
Adapt to Full Pixel Range (icon
button)
When pressed, this sets the color
correction controls so that the entire pixel range of the image is
displayed. So, if the image had a minimum value of 0.1, and a maximum
value of 0.95, it would set the black and white points to 0.1, 0.95.
This is most useful for high dynamic range images and depth maps. For
depth maps, the farthest Z depth value and the closest Z depth value
are ignored (to exclude the cases of a background plate, and 'zero'
depth). The default hotkey for this action is r.
TimeLine Viewer Control Bar
For the timeline viewer, the control
bar is quite different. There are no color correction controls
available in this viewer.
Graph Display Options - Pops up
a menu with 2 options: display time as frames or seconds, and the guide
density (none to high).
Preview Frames - When previews
are on (Ctrl+P), this specifies how often to display the next preview
on the graph bars, in frames.
Graph Viewer Control Bar
The graph viewer has a
RGBA component view control like the
2D viewer. This controls which components are graphed. This is not
supported for all graph types (Hue, Sat and Value graphs require full
RGB).
The other control available is the graph type. The graphs available are:
- Pixel Histogram - This
displays how many times a given pixel value occurred in the image.
Useful for visualizing the distribution of brightness in the image.
- Hue Histogram - This
displays how many times a given hue value occured in the image.
- Saturation Histogram -
This displays how many times a given saturation value occurred in the
image.
- Value Histogram - This
displays how many times a given HSV value occurred in the image.
- Pixel vs U/V - Plots
pixel location (either along U or V) vs the pixels value. This will
show the distribution of pixel values along scanlines or columns. As
multiple values are plotted on top of one another, they become more
white to show the increased density at that point.
- Hue vs U/V - Similar to
the above, but for Hue.
- Saturation vs U/V -
Simalar to the above, but for Saturation.
- Value vs. U/V - Similar
to the above, but for Value.
- Hue vs. Saturation -
Shows how saturated the hues in the image are. If many instances of a
Hue/Saturation occur, the plotted pixel will begin to turn white to
show the increased density.
- Hue vs. Value - Similar
to the above, but this instead shows the values of the Hues in the
image.
Playbar

Play controls
The icon buttons are the basic play
commands. From left to right, these are (with their default hotkey):
- Jump to First Frame
(Ctrl+Left Arrow)
- Back One Frame (Left
Arrow)
- Play Reverse (Down Arrow)
- Stop (Space)
- Play Forward (Up Arrow)
- Advance One Frame (Right
Arrow)
Frame Field
Displays the current frame. Left click
to edit, Middle click to use the popup slider to modify, and Right
click to set the frame to its previous value.
Play slider
Left click to set the new value, left
drag the bar to scub. Middle click uses the popup slider to modify the
frame value, and Right click sets the frame to its previous value.
Frame Range Controls
The frame range is normally hidden.
Press the small '<' button to expand the 2 frame range fields. The
first field contains the start frame, and the second contains the end
frame. The frame bar will play frames between these 2 values.
Frame Rate Field
The current global FPS. This has no
effect unless realtime is on (next button).
Realtime Mode Toggle
Toggles realtime playback. If off,
frames play sequentially as fast as mplay can play them. If on, frames
play back at the rate specified in the Frame Rate field.
Playback Mode Menu
Playback has three different modes:
- Loop - Continuous play of
frames from Start Frame to End frame (or End to Start if playing
backwards).
- Play Once - Plays until
the End frame, and then stops (if playing backwards, it plays until the
Start frame).
- ZigZag - Plays until the
End frame, and then plays backwards to the Start frame, then this
repeats.