python-mvr

Python library for MVR (My Virtual Rig). MVR is part of GDTF (General Device Type Format)

MVR specification as per https://gdtf.eu/mvr/prologue/introduction/

See source code for documentation. Naming conventions, in general, are identical to that on the GDTF, CamelCase is replaced with underscore_delimiters.

This library is used for example by BlenderDMX (BlenderDMX on GitHub).

GitHub Page, PyPi Page

Status

• Reading and Writing of most aspects of MVR 1.6 (DIN SPEC 15801:2023-12) should be covered.
• MVR-xchange is not implemented in this library but full Python implementation exists in BlenderDMX and potentially could be moved here.

Installation

• With uv:

uv add pymvr

• With pip

pip install pymvr

Usage

Reading MVR

import pymvr
mvr_file = pymvr.GeneralSceneDescription("mvr_file.mvr")

for layer_index, layer in enumerate(mvr_file.scene.layers):
    ... #process data

Writing MVR

Validation notes

• Each object now enforces required children/fields when writing. Missing mandatory data will raise ValueError.
• For convenience, fixtures/truss/support/video/projector auto-fill missing IDs with minimal defaults (FixtureID="0", FixtureIDNumeric=0) when not a multipatch child.
• Addresses uses plural fields addresses/networks to align with the spec’s container semantics.
• Required nodes such as Geometries, Source inside MappingDefinition/Projection, and Projections on Projector must be present; empty Sources/Projections will raise.

Load and Export an MVR

import pymvr
from pathlib import Path

# 1. Read MVR file
mvr_read = pymvr.GeneralSceneDescription("mvr_file.mvr")

# 2. Create a writer instance
mvr_writer = pymvr.GeneralSceneDescriptionWriter()

# 3. Serialize the scene object into the writer's XML root
mvr_writer.serialize_scene(mvr_read.scene)

# 4. Serialize the user_data object into the writer's XML root
mvr_writer.serialize_user_data(mvr_read.user_data)

# 5. Add necesarry files like GDTF fixtures, trusses, 3D objects and so on
# Skipped in this example

# 6. Write the MVR file
output_path = Path("exported_mvr_file.mvr")
mvr_writer.write_mvr(output_path)

Creating a new MVR

import pymvr
from pathlib import Path

# 1. Create a writer instance
mvr_writer = pymvr.GeneralSceneDescriptionWriter()

# 2. Build the MVR object tree
# Create a scene object
scene_obj = pymvr.Scene()

# Create layers and add them to the scene
layers = pymvr.Layers()
scene_obj.layers = layers

# Create a layer and add it to the layers
layer = pymvr.Layer(name="Test layer")
layers.append(layer)

# Create a child list for the layer
child_list = pymvr.ChildList()
layer.child_list = child_list

# Create a fixture and add it to the child list
# Note: A valid fixture would require more attributes
fixture = pymvr.Fixture(name="Test Fixture")
child_list.fixtures.append(fixture)

# 3. Serialize the scene object into the writer's XML root
mvr_writer.serialize_scene(scene_obj)

# 4. Add any necessary files (like GDTF fixtures, trusses...) to the MVR archive
#    The list should contain tuples of (file_path, GDTF_file_name)
files_to_pack = []
if fixture.gdtf_spec:
    files_to_pack.append((fixture.gdtf_spec, fixture.gdtf_spec))
mvr_writer.files_list = list(set(files_to_pack))

# 5. Write the MVR file
output_path = Path("exported_mvr_file.mvr")
mvr_writer.write_mvr(output_path)

See BlenderDMX and tests for reference implementation and usage examples.

Changelog

See CHANGELOG for details.

Development

PRs appreciated. You can use uv to get the project setup by running:

uv sync

Format

• To format, use ruff

uv run ruff format pymvr/*

Pre-commit hooks

• You can use the pre-commit hooks

uv run pre-commit install

Testing

• To test, use pytest

uv run pytest

• To test typing with mypy use:

uv run pytest --mypy -m mypy pymvr/*py

Citation

If you use this library in your research, publication, or software project, please cite it as follows:

@software{pymvr2025,
  title        = {pyMVR: Python Library for My Virtual Rig},
  author       = {{OpenStage}},
  year         = {2025},
  version      = {1.0.6},
  url          = {https://github.com/open-stage/python-mvr}
}