Linux ChimeraX can't find ffmpeg

[Tristan Croll]

The following bug report has been submitted:
Platform:        Linux-6.8.0-57-generic-x86_64-with-glibc2.35
ChimeraX Version: 1.10.dev202504300222 (2025-04-30 02:22:20 UTC)
Description
Movie encoding is broken for me in Linux (just double-checked - working fine in 1.9 on the same machine). Says it can't find ffmpeg, but it's in the expected place at /usr/bin/ffmpeg (and /usr/bin is definitely in `os.environ['PATH']`)

Log:
> isolde shorthand
    
    
    Initialising ISOLDE-specific command aliases:
    Alias	Equivalent full command
    -------------------------------------------------
    st	isolde step {arguments}
    aw	isolde add water {arguments}
    awsf	isolde add water {arguments} sim false
    al	isolde add ligand {arguments}
    aa	isolde add aa $1 sel {arguments}
    ht	isolde mod his sel {arguments}
    so	setattr sel atoms occupancy {arguments}
    ab	isolde adjust bfactors {arguments}
    ss	isolde sim start sel
    rt	isolde release torsions sel {arguments}
    rd	isolde release distances sel {arguments}
    ra	rd; rt
    pf	isolde pepflip sel
    cf	isolde cisflip sel
    cbb	color bfactor {arguments}
    cbo	color byattr occupancy {arguments}
    cbc	color {arguments} bychain; color {arguments} byhet
    cs	clipper set contourSensitivity {arguments}
    

  
UCSF ChimeraX version: 1.10.dev202504300222 (2025-04-30)  
© 2016-2025 Regents of the University of California. All rights reserved.  
How to cite UCSF ChimeraX  

> open 3io0

3io0 title:  
Crystal structure of EtuB from Clostridium kluyveri [more info...]  
  
Chain information for 3io0 #1  
---  
Chain | Description | UniProt  
A | EtuB protein | A5N734_CLOK5 75-304  
  
3io0 mmCIF Assemblies  
---  
1| author_and_software_defined_assembly  
  

> movie record size 1920,1080

> movie stop

> movie encode /home/tcroll/Desktop/test.mp4

An error occurred during encoding. See Reply Log for details.  
  
Error during MPEG encoding:  
\-----------------------------  
Exit value: -1  
Error message:  
Could not find ffmpeg executable at ffmpeg  
\-----------------------------  
  




OpenGL version: 3.3.0 NVIDIA 535.230.02
OpenGL renderer: NVIDIA GeForce RTX 3070/PCIe/SSE2
OpenGL vendor: NVIDIA Corporation

Python: 3.11.4
Locale: en_GB.UTF-8
Qt version: PyQt6 6.8.1, Qt 6.8.2
Qt runtime version: 6.8.2
Qt platform: xcb

XDG_SESSION_TYPE=x11
DESKTOP_SESSION=ubuntu
XDG_SESSION_DESKTOP=ubuntu
XDG_CURRENT_DESKTOP=ubuntu:GNOME
DISPLAY=:1
Manufacturer: Dell Inc.
Model: XPS 8950
OS: Ubuntu 22.04
Architecture: 64bit ELF
Virtual Machine: none
CPU: 20 12th Gen Intel(R) Core(TM) i7-12700
Cache Size: 25600 KB
Memory:
	               total        used        free      shared  buff/cache   available
	Mem:            31Gi        24Gi       669Mi       556Mi       5.6Gi       5.2Gi
	Swap:          2.0Gi       2.0Gi       0.0Ki

Graphics:
	0000:01:00.0 VGA compatible controller [0300]: NVIDIA Corporation GA104 [GeForce RTX 3070 Lite Hash Rate] [10de:2488] (rev a1)	
	Subsystem: Dell GA104 [GeForce RTX 3070 Lite Hash Rate] [1028:c903]	
	Kernel driver in use: nvidia

Installed Packages:
    alabaster: 1.0.0
    appdirs: 1.4.4
    asttokens: 3.0.0
    auditwheel: 6.3.0
    babel: 2.17.0
    beautifulsoup4: 4.13.3
    blockdiag: 3.0.0
    blosc2: 3.3.1
    build: 1.2.2.post1
    certifi: 2025.4.26
    cftime: 1.6.4.post1
    charset-normalizer: 3.4.1
    ChimeraX-AddCharge: 1.5.18
    ChimeraX-AddH: 2.2.7
    ChimeraX-AlignmentAlgorithms: 2.0.2
    ChimeraX-AlignmentHdrs: 3.6.1
    ChimeraX-AlignmentMatrices: 2.1
    ChimeraX-Alignments: 2.20.1
    ChimeraX-AlphaFold: 1.0.1
    ChimeraX-AltlocExplorer: 1.1.2
    ChimeraX-AmberInfo: 1.0
    ChimeraX-Aniso: 1.1.3
    ChimeraX-Arrays: 1.1
    ChimeraX-Atomic: 1.60.5
    ChimeraX-AtomicLibrary: 14.1.17
    ChimeraX-AtomSearch: 2.0.1
    ChimeraX-AxesPlanes: 2.4
    ChimeraX-BasicActions: 1.1.3
    ChimeraX-BILD: 1.0
    ChimeraX-BlastProtein: 3.0.0
    ChimeraX-Boltz: 1.0
    ChimeraX-BondRot: 2.0.4
    ChimeraX-BugReporter: 1.0.2
    ChimeraX-BuildStructure: 2.13.1
    ChimeraX-Bumps: 1.0
    ChimeraX-BundleBuilder: 1.4.0
    ChimeraX-ButtonPanel: 1.0.1
    ChimeraX-CageBuilder: 1.0.1
    ChimeraX-CellPack: 1.0
    ChimeraX-Centroids: 1.4
    ChimeraX-ChangeChains: 1.1
    ChimeraX-CheckWaters: 1.4
    ChimeraX-ChemGroup: 2.0.2
    ChimeraX-Clashes: 2.3
    ChimeraX-Clipper: 0.25.0
    ChimeraX-ColorActions: 1.0.5
    ChimeraX-ColorGlobe: 1.0
    ChimeraX-ColorKey: 1.5.8
    ChimeraX-CommandLine: 1.2.6
    ChimeraX-ConnectStructure: 2.0.1
    ChimeraX-Contacts: 1.0.1
    ChimeraX-Core: 1.10.dev202504300222
    ChimeraX-CoreFormats: 1.2
    ChimeraX-coulombic: 1.4.5
    ChimeraX-Crosslinks: 1.0
    ChimeraX-Crystal: 1.0
    ChimeraX-CrystalContacts: 1.0.1
    ChimeraX-DataFormats: 1.2.4
    ChimeraX-Dicom: 1.2.7
    ChimeraX-DistMonitor: 1.4.2
    ChimeraX-DockPrep: 1.1.4
    ChimeraX-Dssp: 2.0
    ChimeraX-EMDB-SFF: 1.0
    ChimeraX-ESMFold: 1.0
    ChimeraX-FileHistory: 1.0.1
    ChimeraX-FunctionKey: 1.0.1
    ChimeraX-Geometry: 1.3
    ChimeraX-gltf: 1.0
    ChimeraX-Graphics: 1.4.1
    ChimeraX-Hbonds: 2.5.1
    ChimeraX-Help: 1.3
    ChimeraX-HKCage: 1.3
    ChimeraX-IHM: 1.1
    ChimeraX-ImageFormats: 1.2
    ChimeraX-IMOD: 1.0
    ChimeraX-IO: 1.0.3
    ChimeraX-ISOLDE: 1.10rc0
    ChimeraX-ItemsInspection: 1.0.1
    ChimeraX-IUPAC: 1.0
    ChimeraX-KVFinder: 1.6.1
    ChimeraX-Label: 1.1.14
    ChimeraX-LinuxSupport: 1.0.1
    ChimeraX-ListInfo: 1.2.2
    ChimeraX-Log: 1.2
    ChimeraX-LookingGlass: 1.1
    ChimeraX-Maestro: 1.9.1
    ChimeraX-Map: 1.3
    ChimeraX-MapData: 2.0
    ChimeraX-MapEraser: 1.0.1
    ChimeraX-MapFilter: 2.0.1
    ChimeraX-MapFit: 2.0
    ChimeraX-MapSeries: 2.1.1
    ChimeraX-Markers: 1.0.1
    ChimeraX-Mask: 1.0.2
    ChimeraX-MatchMaker: 2.2.1
    ChimeraX-MCopy: 1.0
    ChimeraX-MDcrds: 2.10.1
    ChimeraX-MedicalToolbar: 1.1
    ChimeraX-Meeting: 1.0.1
    ChimeraX-MLP: 1.1.1
    ChimeraX-mmCIF: 2.16
    ChimeraX-MMTF: 2.2
    ChimeraX-ModelArchive: 1.0
    ChimeraX-Modeller: 1.5.19
    ChimeraX-ModelPanel: 1.5.1
    ChimeraX-ModelSeries: 1.0.1
    ChimeraX-Mol2: 2.0.3
    ChimeraX-Mole: 1.0
    ChimeraX-Morph: 1.0.2
    ChimeraX-MouseModes: 1.2
    ChimeraX-Movie: 1.0
    ChimeraX-MutationScores: 1.0
    ChimeraX-Neuron: 1.0
    ChimeraX-Nifti: 1.2
    ChimeraX-NMRSTAR: 1.0.2
    ChimeraX-NRRD: 1.2
    ChimeraX-Nucleotides: 2.0.3
    ChimeraX-OpenCommand: 1.14.1
    ChimeraX-OrthoPick: 1.0.1
    ChimeraX-PDB: 2.7.9
    ChimeraX-PDBBio: 1.0.1
    ChimeraX-PDBLibrary: 1.0.4
    ChimeraX-PDBMatrices: 1.0
    ChimeraX-PickBlobs: 1.0.1
    ChimeraX-Positions: 1.0
    ChimeraX-PresetMgr: 1.1.3
    ChimeraX-ProfileGrids: 1.1.1
    ChimeraX-PubChem: 2.2
    ChimeraX-ReadPbonds: 1.0.1
    ChimeraX-Registration: 1.1.2
    ChimeraX-RemoteControl: 1.0
    ChimeraX-RenderByAttr: 1.6.3
    ChimeraX-RenumberResidues: 1.1
    ChimeraX-ResidueFit: 1.0.1
    ChimeraX-RestServer: 1.3.1
    ChimeraX-RNALayout: 1.0
    ChimeraX-RotamerLibMgr: 4.0
    ChimeraX-RotamerLibsDunbrack: 2.0
    ChimeraX-RotamerLibsDynameomics: 2.0
    ChimeraX-RotamerLibsRichardson: 2.0
    ChimeraX-SaveCommand: 1.5.1
    ChimeraX-SchemeMgr: 1.0
    ChimeraX-SDF: 2.0.3
    ChimeraX-Segger: 1.0
    ChimeraX-Segment: 1.0.1
    ChimeraX-Segmentations: 3.5.7
    ChimeraX-SelInspector: 1.0
    ChimeraX-SeqView: 2.17.1
    ChimeraX-Shape: 1.1
    ChimeraX-Shell: 1.0.1
    ChimeraX-Shortcuts: 1.2.0
    ChimeraX-ShowSequences: 1.0.3
    ChimeraX-SideView: 1.0.1
    ChimeraX-SimilarStructures: 1.0.1
    ChimeraX-Smiles: 2.1.2
    ChimeraX-SmoothLines: 1.0
    ChimeraX-SpaceNavigator: 1.0
    ChimeraX-StdCommands: 1.19.1
    ChimeraX-STL: 1.0.1
    ChimeraX-Storm: 1.0
    ChimeraX-StructMeasure: 1.2.1
    ChimeraX-Struts: 1.0.1
    ChimeraX-Surface: 1.0.1
    ChimeraX-SwapAA: 2.0.1
    ChimeraX-SwapRes: 2.5.2
    ChimeraX-TapeMeasure: 1.0
    ChimeraX-TaskManager: 1.0
    ChimeraX-Test: 1.0
    ChimeraX-Toolbar: 1.2.3
    ChimeraX-ToolshedUtils: 1.2.4
    ChimeraX-Topography: 1.0
    ChimeraX-ToQuest: 1.0
    ChimeraX-Tug: 1.0.1
    ChimeraX-UI: 1.45.1
    ChimeraX-Umap: 1.0
    ChimeraX-uniprot: 2.3.1
    ChimeraX-UnitCell: 1.0.1
    ChimeraX-ViewDockX: 1.4.4
    ChimeraX-VIPERdb: 1.0
    ChimeraX-Vive: 1.1
    ChimeraX-VolumeMenu: 1.0.1
    ChimeraX-vrml: 1.0
    ChimeraX-VTK: 1.0
    ChimeraX-WavefrontOBJ: 1.0
    ChimeraX-WebCam: 1.0.2
    ChimeraX-WebServices: 1.1.4
    ChimeraX-Zone: 1.0.1
    colorama: 0.4.6
    comm: 0.2.2
    contourpy: 1.3.2
    coverage: 7.8.0
    cxservices: 1.2.3
    cycler: 0.12.1
    Cython: 3.0.12
    debugpy: 1.8.14
    decorator: 5.2.1
    distro: 1.9.0
    docutils: 0.21.2
    executing: 2.2.0
    filelock: 3.18.0
    fonttools: 4.57.0
    funcparserlib: 2.0.0a0
    glfw: 2.9.0
    grako: 3.16.5
    h5py: 3.13.0
    html2text: 2024.2.26
    idna: 3.10
    ihm: 2.2
    imagecodecs: 2024.6.1
    imagesize: 1.4.1
    iniconfig: 2.1.0
    ipykernel: 6.29.5
    ipython: 8.26.0
    ipywidgets: 8.1.6
    jedi: 0.19.1
    Jinja2: 3.1.6
    jupyter_client: 8.6.3
    jupyter_core: 5.7.2
    jupyterlab_widgets: 3.0.14
    kiwisolver: 1.4.8
    line_profiler: 4.2.0
    lxml: 5.3.1
    lz4: 4.4.4
    MarkupSafe: 3.0.2
    matplotlib: 3.10.1
    matplotlib-inline: 0.1.7
    msgpack: 1.1.0
    ndindex: 1.9.2
    nest-asyncio: 1.6.0
    netCDF4: 1.6.5
    networkx: 3.3
    nibabel: 5.2.0
    nptyping: 2.5.0
    numexpr: 2.10.2
    numpy: 1.26.4
    OpenMM: 8.1.1
    OpenMM: 8.2.0
    openmm-cuda: 8.1.1.11.8
    openvr: 1.26.701
    packaging: 24.2
    ParmEd: 4.2.2
    parso: 0.8.4
    pep517: 0.13.1
    pexpect: 4.9.0
    pickleshare: 0.7.5
    pillow: 10.4.0
    pip: 25.0.1
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    platformdirs: 4.3.7
    pluggy: 1.5.0
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    psutil: 7.0.0
    ptyprocess: 0.7.0
    pure_eval: 0.2.3
    py-cpuinfo: 9.0.0
    pycollada: 0.8
    pydicom: 2.4.4
    pyelftools: 0.32
    Pygments: 2.18.0
    pynmrstar: 3.3.5
    pynrrd: 1.0.0
    PyOpenGL: 3.1.9
    PyOpenGL-accelerate: 3.1.9
    pyopenxr: 1.1.4501
    pyparsing: 3.2.3
    pyproject_hooks: 1.2.0
    PyQt6: 6.8.1
    PyQt6-Qt6: 6.8.2
    PyQt6-WebEngine: 6.8.0
    PyQt6-WebEngine-Qt6: 6.8.2
    PyQt6_sip: 13.10.0
    pytest: 8.3.5
    pytest-cov: 6.1.1
    python-dateutil: 2.9.0.post0
    pytz: 2025.2
    pyzmq: 26.4.0
    qtconsole: 5.5.2
    QtPy: 2.4.3
    qtshim: 1.1
    RandomWords: 0.4.0
    requests: 2.32.3
    roman-numerals-py: 3.1.0
    scipy: 1.14.0
    setuptools: 78.1.0
    sfftk-rw: 0.8.1
    six: 1.16.0
    snowballstemmer: 2.2.0
    sortedcontainers: 2.4.0
    soupsieve: 2.7
    Sphinx: 8.2.3
    sphinx-autodoc-typehints: 3.1.0
    sphinxcontrib-applehelp: 2.0.0
    sphinxcontrib-blockdiag: 3.0.0
    sphinxcontrib-devhelp: 2.0.0
    sphinxcontrib-htmlhelp: 2.1.0
    sphinxcontrib-jsmath: 1.0.1
    sphinxcontrib-qthelp: 2.0.0
    sphinxcontrib-serializinghtml: 2.0.0
    stack-data: 0.6.3
    superqt: 0.7.1
    tables: 3.10.2
    tcia_utils: 1.5.1
    tifffile: 2025.3.13
    tinyarray: 1.2.4
    tornado: 6.4.2
    traitlets: 5.14.3
    typing_extensions: 4.13.2
    tzdata: 2025.2
    urllib3: 2.4.0
    wcwidth: 0.2.13
    webcolors: 24.11.1
    wheel: 0.45.1
    wheel-filename: 1.4.2
    widgetsnbextension: 4.0.14

[Greg Couch]

It's difficult to see how this could happen. ffmpeg is a dependency for ChimeraX on Ubuntu, so /usr/bin/ffpmeg should exist. Is /usr/bin not on your path?

[Tristan Croll]

That’s what’s confusing. ffmpeg is there, and /usr/bin is definitely on the
path. I did notice that every time I attempted “movie encode” in ChimeraX
1.10 it echoed “/usr/bin/ffmpeg” to the terminal, and that *didn’t* happen
when I (successfully) used “movie encode” in 1.9 at about the same time.
Don’t know what that means, but it feels like a clue.

On Thu, 22 May 2025 at 21:33, ChimeraX <ChimeraX-bugs-admin@cgl.ucsf.edu>
wrote:

>
>

[Zach Pearson]

Sorry for the delay in addressing this ticket, I've been down with COVID. Recently, I made a modification to the movie bundle that tries to prefer the system ffmpeg on Linux, so that the Flatpak builds can use the Flatpak ffmpeg. It only looks for ChimeraX's ffmpeg on Windows, or if 'which ffmpeg' returns an error.

[Greg Couch]

Zach, how about ripping out all of those changes and just adding the ChimeraX bin directory at the end of the path, so a system version takes precedence?

[Zach Pearson]

Sounds good to me!

[Zach Pearson]

OK, I made that change and tested with a spin movie on Ubuntu 22