Capabilities

GET /api/capabilities

Requires: read (viewer+)

Returns static hardware and software capabilities of this Composer instance: CUDA devices, NVENC/NVDEC support, NDI runtime, DeckLink devices, fonts, disk space, and FFmpeg. Read-only, responds immediately. Useful for capacity planning, feature-gate checks, and diagnostic tooling.

The same snapshot is also served by the Runtime API at GET /runtime/capabilities; that endpoint remains available while the project is in Idle state, whereas /api/capabilities is gated by DisableWebApiWhenNotRunning like the other project-level endpoints.

Parameters: None

Response: 200 OK — JSON object:

{
  "runtime": {
    "binaryPath": "C:\\Program Files\\Vindral Composer\\VindralComposerDesktop.exe",
    "version": "2.6.9609.28197"
  },
  "cuda": {
    "driverVersion": "12.40",
    "deviceCount": 1,
    "activeDeviceId": 0,
    "devices": [
      {
        "index": 0,
        "name": "NVIDIA GeForce RTX 4090",
        "computeCapability": "8.9",
        "totalMemoryMb": 24564,
        "multiProcessorCount": 128,
        "clockRateMhz": 2520,
        "memoryClockRateMhz": 10501,
        "computeMode": "Default",
        "tccDriver": false,
        "eccEnabled": false,
        "pciBusId": 1,
        "pciDeviceId": 0
      }
    ]
  },
  "nvenc": {
    "available": true,
    "supportedCodecs": ["H264", "HEVC", "AV1"],
    "maxConcurrentSessions": "8"
  },
  "nvdec": {
    "codecs": [
      {
        "codec": "H264",
        "bitDepth": 8,
        "supported": true,
        "numDecoders": 2,
        "maxWidth": 4096,
        "maxHeight": 4096,
        "minWidth": 48,
        "minHeight": 48
      }
    ]
  },
  "ndi": {
    "runtimePresent": true
  },
  "decklink": {
    "devices": ["DeckLink Mini Recorder 4K"],
    "channels": [
      { "index": 0, "name": "DeckLink Mini Recorder 4K (1)" }
    ]
  },
  "fonts": {
    "count": 245,
    "families": ["Arial", "Calibri", "..."]
  },
  "storage": {
    "drives": [
      {
        "name": "C:\\",
        "totalSizeMb": 953869,
        "availableFreeMb": 512345,
        "format": "NTFS",
        "type": "Fixed"
      }
    ]
  },
  "ffmpeg": {
    "version": "6.1.1-realsprint",
    "path": "C:\\ffmpeg6p2\\bin\\",
    "executable": "C:\\ffmpeg6p2\\bin\\ffmpeg.exe"
  },
  "timestamp": "2026-04-24T12:00:00.0000000Z"
}

Each subsystem is gathered in its own try/catch; on a per-section failure, that subsection is replaced by { "error": "<message>" } so a single broken query (e.g. FFmpeg not loaded) does not break the rest of the response.

Response fields:

`runtime` object

Field	Type	Description
`binaryPath`	string	Full path to the running Composer executable (Desktop or Runtime)
`version`	string	Assembly version of the entry binary

`cuda` object

Field	Type	Description
`driverVersion`	string	NVIDIA CUDA driver version
`deviceCount`	int	Number of CUDA-capable devices
`activeDeviceId`	int	Device index selected by Composer for rendering
`devices`	array	Per-device details (see below)

Each device:

Field	Type	Description
`index`	int	Device index
`name`	string	GPU product name
`computeCapability`	string	CUDA compute capability (e.g. "8.9")
`totalMemoryMb`	long	Total GPU memory in MB
`multiProcessorCount`	int	Number of streaming multiprocessors
`clockRateMhz`	int	Core clock rate in MHz
`memoryClockRateMhz`	int	Memory clock rate in MHz
`computeMode`	string	CUDA compute mode (Default, ExclusiveThread, Prohibited, ExclusiveProcess)
`tccDriver`	bool	Whether TCC (Tesla Compute Cluster) driver mode is active
`eccEnabled`	bool	Whether ECC memory is enabled
`pciBusId`	int	PCI bus ID
`pciDeviceId`	int	PCI device ID

`nvenc` object

Field	Type	Description
`available`	bool	Whether NVENC hardware encoding is available
`supportedCodecs`	string[]	Codecs the GPU can encode (H264, HEVC, AV1)
`maxConcurrentSessions`	string	Max concurrent encode sessions ("8" for GeForce/consumer, "unlimited" for professional/datacenter)

`nvdec` object

codecs array — each entry:

Field	Type	Description
`codec`	string	Codec name (H264, HEVC, VP9, AV1)
`bitDepth`	int	Bit depth (8 or 10)
`supported`	bool	Whether this codec/depth combo is supported
`numDecoders`	int	Number of NVDEC engines on the GPU
`maxWidth`	uint	Maximum decode width in pixels
`maxHeight`	uint	Maximum decode height in pixels
`minWidth`	int	Minimum decode width in pixels
`minHeight`	int	Minimum decode height in pixels

`ndi` object

Field	Type	Description
`runtimePresent`	bool	Whether the NDI runtime library is installed and initialized

`decklink` object

Field	Type	Description
`devices`	string[]	Distinct DeckLink device names
`channels`	array	Per-channel details with `index` and `name`

`fonts` object

Field	Type	Description
`count`	int	Total number of installed font families
`families`	string[]	Sorted list of font family names

`storage` object

drives array — each entry:

Field	Type	Description
`name`	string	Drive root path (e.g. "C:\")
`totalSizeMb`	long	Total drive size in MB
`availableFreeMb`	long	Available free space in MB
`format`	string	File system format (NTFS, ext4, etc.)
`type`	string	Drive type (Fixed, Removable, Network, etc.)

`ffmpeg` object

Field	Type	Description
`version`	string	FFmpeg version string as reported by `av_version_info()`
`path`	string	Path to the FFmpeg libraries in use (Windows: `bin` directory; Linux: `.so` library directory)
`executable`	string	Absolute path to the `ffmpeg` executable, or `""` if it could not be resolved. On Windows this is `path\ffmpeg.exe`; on Linux it is the first `ffmpeg` found on `$PATH`

Capabilities

GET /api/capabilities

runtime object

cuda object

nvenc object

nvdec object

ndi object

decklink object

fonts object

storage object

ffmpeg object