Raven - OTIO Viewer

An experimental re-write of OpenTimelineIO's otioview timeline viewer application.

This tool aims to replace otioview but it is missing a few essential features (see "Help Wanted" and "To Do" below). Contributions are welcome!

Dependencies

macOS:

• Standard Apple developer toolchain (installed with Xcode)
• A recent version of CMake
  • You can get this via brew install cmake or by downloading from https://cmake.org/download/

Windows:

• Standard Microsoft developer toolchain (installed with Visual Studio)
• A recent version of CMake

Linux (Ubuntu, or similar):

• sudo apt-get install libglfw3-dev libgtk-3-dev
• A recent version of CMake
  • You can get this via sudo snap install cmake or by downloading from https://cmake.org/download/

Note: Before building, please ensure that you clone this project with the --recursive flag. This will also clone and initialize all of the submodules that this project depends on.

Building (macOS, Windows, Linux)

Spin up your favourite terminal and follow these steps:

  git submodule update --init --recursive
  mkdir build
  cd build
  cmake ..
  cmake --build . -j
  ./raven ../example.otio

Building (WASM via Emscripten)

You will need to install the Emscripten toolchain first.

  git submodule update --init --recursive
  mkdir build-web
  cd build-web
  emcmake cmake ..
  cmake --build .
  emrun ./raven.html

See also: serve.py as an alternative to emrun, and as a reference for which HTTP headers are needed to host the WASM build.

You can load a file into WASM Raven a few ways:

• Add a JSON string to Module.otioLoadString in the HTML file
• Add a URL to Module.otioLoadURL in the HTML file
• Call Module.LoadString(otio_data) at runtime
• Call Module.LoadURL(otio_url) at runtime

Note: The WASM build of raven is missing some features - see the Help Wanted section below.

Troubleshooting

If you have trouble building, these hints might help...

You might need to init/update submodules:

% git submodule init
% git submodule update

You might be missing some dependencies (see above).

See also .github/workflows/build.yaml for a working example of building on each of the platforms listed above.

Example files

The examples folder contains some example .otio files for testing.

The El Fuente and Meridian examples provided by Netflix (under the Creative Commons Attribution 4.0 International Public License) were converted to OTIO, along with several other examples here.

Thanks

Raven was made possible by these excellent libraries:

• OpenTimelineIO (Apache 2.0)
• Dear ImGui (MIT)
• ImPlot (MIT)
• ImGuiColorTextEdit (MIT)
• glfw (Zlib)
• nativefiledialog (Zlib)

Help Wanted

• Fully standalone cross-platform build:
  • Mac
    • App bundle
    • Code signing?
  • Linux
    • CI is building, does it actually run?
  • Emscripten
    • Where can we host this? (needs specific HTTP headers? See serve.py)
    • Needs file open/save dialog
      • Maybe this could work in app.cpp's OpenFileDialog() and SaveFileDialog()?
      • or this: https://github.com/Armchair-Software/emscripten-browser-file
      • See the web-file-open branch
    • Avoid continuous rendering
      • Is there an equivalent to ImGui_ImplGlfw_WaitForEvent() that works with SDL2 + Emscripten?
  • Easily downloadable pre-built binaries
• JSON Inspector:
  • Edit JSON to replace selected object?
    • This would let you explore & understand how changes affect the composition
  • When loading a very large OTIO, the JSON inspector can double the load time (full feature film ~45 seconds)
• Multiple selection, copy, paste, undo, redo
• Various operations from otiotool

To Do

• Feature parity with otioview:
  • Show media reference details in the Inspector
  • Double-click to expand/collapse nested compositions
  • Arrow keys to navigate by selection
    • This sort of works already via ImGui's navigation system, but it is too easy to get stuck on a marker, or to walk out of the timeline.
    • Can this be rectified by turning off keyboard navigation on the widgets outside the timeline?
  • Multiple timelines in separate tabs or windows?
    • Look at ImGui document-based demo code for reference.
    • Might be fine to just open multiple instances of the app.
  • Add support for adapters
    • Use embedded Python, or run otioconvert via pipe?
    • Constraint: We want to ensure this tool stays light weight, and works in the browser.
• Enhancements:
  • Double-click a Clip to expand/collapse it's media reference
  • Show time-warped ruler inside media reference or nested composition
• Performance optimization:
  • Avoid rendering tracks outside the scroll region
  • Avoid rendering items smaller than a tiny sliver
  • Experiment with drawing the timeline without using a Dear ImGui table
    • Results so far: aligning multiple scroll regions causes 1-frame lag which is ugly
• Inspector:
  • Show summarized timing information (ala otiotool --inspect)
  • Range slider could be useful:
    • ocornut/imgui#76 (comment)
  • Per-schema inspector GUI
    • Items:
      • enable/disable
    • Clips:
      • show media_reference(s)
      • adjust available_range of media reference
      • edit target_url
    • Transitions:
      • nicer GUI for adjusting in/out offsets
      • avoid extending beyond range of adjacent Items
      • avoid overlap with adjacent Transitions
    • Markers:
      • color picker
    • Compositions:
      • show source_range limits in the timeline
    • LinearTimeWarp:
      • time_scale graph could be nicer
    • FreezeFrame:
    • UnknownSchema:
      • Can we show properties via SerializableObject's introspection?