DJV

DJV is an open source application for media playback and review. DJV can playback high resolution image sequences and movies in real time, with audio, A/B comparison, color management, and more.

Features include:

• Support for high resolution and high bit depth images
• A/B comparison with wipe, overlay, and difference modes
• Timeline support with OpenTimelineIO
• Color management with OpenColorIO
• Multi-track audio with variable speed and reverse playback
• Experimental support for USD files
• Available for Linux, macOS, and Windows

Documentation

1. Download and Install
2. Main Window
3. Files
4. Viewport
5. Playback and Frame Control
6. Timeline
7. A/B Comparison
8. Color
9. Exporting Files
10. Settings
11. Keyboard Shortcuts
12. Troubleshooting

Download and Install

Downloads

NOTE: Download packages only include a minimal set of video and audio codecs. To enable full support, either compile from source or replace the FFmpeg shared libraries.

Linux

Packages are distributed as tar archives. Uncompress the archive and move the DJV folder to a convenient location.

Windows

Packages are distributed as ZIP archives. Uncompress the archive and move the DJV folder to a convenient location.

macOS

Packages are distributed as macOS disk images. Open the disk image and copy DJV to the “Applications” folder.

Main Window

Main window:

1. Tab Bar - Switch between currently opened files
2. Viewport - View of the current file
3. Timeline - Time scrubbing, thumbnails, and audio waveforms
4. Playback - Playback and frame controls
5. Tool - Current tool (e.g. color picker or magnifier)
6. Status Bar - Warnings, errors, information about the current file, and status indicators

Parts of the user interface can be toggled on and off from the Window menu.

Full screen mode can be enabled from the Window menu.

A secondary window can be used to mirror the viewport on a separate monitor. The secondary window can be shown from the Window menu.

Files

Supported file formats:

• Image sequences: Cineon, DPX, JPEG, OpenEXR, PNG, PPM, SGI, TGA, BMP, TIFF
• Default movie codecs: MJPEG, MPEG-2
• Default audio codecs: FLAC, MP3, WAV
• Timelines: OTIO, OTIOZ
• Experimental: USD

Files and folders can be opened from the File menu, by dragging and dropping onto the main window, or from the command line. Opening a folder will open all of the supported files in the folder (non-recursively).

Image sequences can be opened from the command line by either specifying the first frame or using the “#” wildcard. For example:

djv render.#.exr

The native file browser is enabled by default on Windows and macOS. The built-in file browser can be enabled in the Settings tool.

The current file can be changed from the File/Current menu, the Tab Bar, or the Files tool.

Memory Cache

The memory cache can be configured in the Settings tool. There are separate values for video, audio, and “read behind”. The “read behind” value is the number of seconds that are read before the current frame. This is useful to ensure frames are cached when scrubbing.

Only the current file is stored in the cache. When the current file is changed, it is cleared from the cache and the new file is loaded into the cache.

Layers

For files that contain multiple layers (i.e., OpenEXR), the current layer can be changed from the File/Layers menu or the Files tool.

Files Tool

The Files tool can be used to set the current file, the current layers, and compare options.

The Files tool can be shown from the Tools menu or the tool bar.

Files tool:

1. Current file (A file)
2. B files (multiple “B” files may be set for tile mode)
3. Current layer
4. Compare mode
5. Compare time
6. Compare options

Image Sequences and Audio

Audio can be added to image sequences either automatically or explicitly.

To automatically add audio to image sequences, open the Image Sequences section in the Settings Tool. Audio files can be found by either specifying the file extensions to search for (e.g., “.wav .mp3”), or providing a specific file name.

To explicitly add audio to an image sequence use the File/Open With Audio menu.

USD

USD file support is currently experimental. When a USD file is opened it is rendered to an image sequence with the Hydra renderer.

The camera used to render the scene will be chosen in this order:

1. If the USD file is referenced from an OTIO file, the name of the clip
2. The primary camera in the scene
3. The first camera found in the scene
4. A temporary camera is created that frames the scene

Viewport

The viewport shows a view of the current file. The view can be panned, zoomed, or “framed” so the image fills the view.

Viewport controls:

• Pan - Middle mouse button
• Zoom - Mouse wheel or keyboard shortcuts - and =
• Frame view - Keyboard shortcut Backspace
• Wipe in compare mode - Alt + left mouse button
• Color picker - Ctrl + left mouse button
• Frame shuttle - Left mouse button

The viewport controls can be customized in the Settings tool.

The bit depth of the viewport can be set in the View tool with the color buffer option. The default option of RGBA F32 is recommended to avoid clamping color values. The other opions may be used for extra performance but with possible color clamping.

The background color of the viewport can be set in the View tool. An outline can also be drawn around the image to disinguish it from the background, which can be useful for images with transparency.

Grid

The grid can be enabled from the View tool.

Grid options:

• Enabled: Toggle the grid on or off
• Size: Number of pixels between grid lines
• Line width: Width of the grid lines
• Color: Color of the grid lines
• Labels:
  • None: No labels
  • Pixels: Pixel positions
  • Alphanumeric: Letters in the X direction and numbers in the Y direction (e.g., “B 12”)
• Text color: Label text color
• Overlay color: Label background color

The grid can be used to examine individual pixels with these settings:

1. Set Magnify to Nearest
2. Enable the grid
3. Set the grid size to one

HUD

Information can be overlaid on the viewport by enabling the HUD (heads up display). The HUD can be enabled from the View menu.

HUD:

1. Current file name
2. Current frame
3. Real playback speed
4. Number of frames dropped during playback
5. Color picker
6. Video cache percentage
7. Audio cache percentage

Playback and Frame Control

Playback and frame controls:

1. Playback controls
2. Playback shuttle - Click and drag to change playback speed
3. Frame controls
4. Frame shuttle - Click and drag to change the current frame
5. Current frame
6. Duration
7. Current speed
8. Speed multiplier
9. Time units (e.g., frames or timecode)

The playback speed can be changed momentarily by clicking forward or reverse multiple times. The speed will accelerate 2X with each click, and can be slowed down by clicking the opposite playback direction. The speed “multiplier” is displayed with the other playback controls.

In and out points can be set frome the Playback menu to limit playback to a section of the timeline.

The number of dropped frames during playback can be viewed in the HUD, which is available from the View menu.

Timeline

By default the timeline is minimized, showing only the first video and audio track. To see all of the tracks in the timeline, toggle the minimized state available from the Timeline menu.

Timeline:

1. Current frame
2. In/out range (blue)
3. Video cache display (green)
4. Audio cache display (purple)
5. Video track
6. Video clips
7. Audio track
8. Audio clips

Timeline controls:

• Change the current frame - Left mouse button
• Zoom - Mouse wheel or keyboard shortcuts - and =
• Frame view - Keyboard shortcut Backspace
• Pan - Middle mouse button

The size of the timeline thumbnails can be set from the Timeline menu. Thumbnails can also be disabled to improve performance.

A/B Comparison

To compare files, open both files and set the B file from either the Compare/B menu or Files tool. The A file is the current file.

Compare modes:

• A - Show only the A file
• B - Show only the B file
• Wipe - Wipe between the A and B files
• Overlay - Show the B file over the A file
• Difference - Show the difference between the A and B files
• Horizontal - Show the A and B files side by side
• Vertical - Show the A and B files over and under
• Tile - Show the A and B files as tiles

Multiple B files can be viewed with Tile mode.

One example use for Tile mode is to simultaneously view multiple layers within a file. Open the file multiple times and set the current layer for each instance. Then enable Tile compare mode and set the “B” files.

Compare multiple layers:

1. Set the compare mode to Tile
2. Set the current file and layer
3. Set multiple B files and their layers

Files can be compared in relative or absolute time mode. In relative time mode the time of the B file will be offset to match the start of the A file. In absolute time mode the A and B times will be the same.

Color

The Color tool can be used to set OpenColorIO options, specify a LUT (Look-Up Table), or apply other controls like brightness, contrast, and levels.

The Color tool can be shown from the Tools menu or the tool bar.

OpenColorIO options:

1. Enable OpenColorIO
2. OpenColorIO configuration
3. Configuration name
4. Input color space
5. Display color space
6. View color space
7. Look color space

The OpenColorIO configuration can be set to a built-in configuration, the OCIO environment variable, or a file name.

A LUT file can also be applied either before or after the OpenColorIO pass, by setting the LUT Order option to PreColorConfig or PostColorConfig.

Exporting Files

The Export tool can be used to export the current file as an image sequence, a movie, or the current frame as a still image.

The Export tool can be shown from the Tools menu or the tool bar.

Export:

1. Output directory
2. Render size
3. File type
4. Base file name
5. File extension
6. Movie codec
7. Export button

To export an image sequence set the file type to Sequence. To export the current frame set the file type to Image.

The current layer, playback speed, in/out range, and color settings will be exported.

Note that audio export is not yet supported.

Settings

Settings are stored as a JSON file in the DJV folder in your Documents directory.

Keyboard Shortcuts

Keyboard shorcuts can be customized in the Settings tool.

The Settings tool can be shown from the Tools menu or the tool bar.

Keyboard shortcuts:

1. Keyboard shortcuts settings
2. Seach shortcuts
3. Shortcut with keyboard focus
4. Secondary shortcut
5. Conflicting shortcuts

To set a shortcut, click the shortcut widget or use the tab key to give it keyboard focus, then type the new shortcut. The widget will turn red if the shortcut conflicts with another one.

Troubleshooting

Check the log file located in the DJV folder in your Documents directory.

If the application fails to start, try running from the command line to check for are any errors:

djv -log

Reset the settings:

• Delete the DJV folder in your Documents directory
• Or pass the -resetSettings flag on the command line

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