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Configuration

This section details the environment variables used for the Smelter deployment configuration. Every environment variable listed below is optional.

SMELTER_API_PORT

API port of the Smelter API.

  • Defaults to: 8081

SMELTER_INSTANCE_ID

ID returned from GET /status request. Can be used to verify that a connection was established to the correct smelter instance.

  • Defaults to: the random number

SMELTER_OUTPUT_FRAMERATE

Output framerate for all output streams.

  • Defaults to: 30
  • Supported values:
    • number
    • string in the NUM/DEN format, where both NUM and DEN are unsigned integers

SMELTER_OUTPUT_SAMPLE_RATE

Output sample rate for all output streams.

  • Defaults to: 48000
  • Supported values:
    • Sample rates (8000, 12000, 16000, 24000, 48000) in number or string format

SMELTER_FORCE_GPU

If enabled, GPU will be required for rendering. If only CPU based adapters will be found then process will exit with an error.

  • Defaults to: false
  • Supported values:
    • true or 1, to enable
    • false or 0, to disable

SMELTER_STREAM_FALLBACK_TIMEOUT_MS

Timeout duration (in ms) that specifies when the smelter should switch to a fallback option if the input stream ceases to send frames.

  • Defaults to: 500

SMELTER_LOGGER_LEVEL

Value or configuration string that specifies the granularity of log capture.

  • Defaults to: info,wgpu_hal=warn,wgpu_core=warn
  • Supported values:
    • error, warn, info, debug, trace
    • string containing tracing-subscriber configuration (see documentation for more details)

SMELTER_LOGGER_FORMAT

Logger output format.

  • Defaults to: json
  • Supported values:
    • json, compact, pretty

SMELTER_FFMPEG_LOGGER_LEVEL

Value that specifies the granularity of log capture for FFmpeg.

  • Defaults to: warn
  • Supported values:
    • error - equivalent to FFmpeg’s error, 16
    • warn - equivalent to FFmpeg’s warning, 24
    • info - equivalent to FFmpeg’s info, 32
    • debug - equivalent to FFmpeg’s debug, 48

See -loglevel option in FFmpeg docs for more details.

SMELTER_DOWNLOAD_DIR

Path specifying where to store downloaded files.

  • Defaults to: the location provided by the OS

SMELTER_WEB_RENDERER_ENABLE

If enabled, Smelter will support web rendering capabilities.

  • Defaults to: false
  • Supported values:
    • true or 1, to enable
    • false or 0, to disable

SMELTER_WEB_RENDERER_GPU_ENABLE

If enabled, Smelter will support GPU inside the embedded Chromium instance.

  • Defaults to: true
  • Supported values:
    • true or 1, to enable
    • false or 0, to disable

SMELTER_OFFLINE_PROCESSING_ENABLE

If enabled, sets SMELTER_AHEAD_OF_TIME_PROCESSING_ENABLE and SMELTER_NEVER_DROP_OUTPUT_FRAMES options to true. If those options are also defined they take priority over SMELTER_OFFLINE_PROCESSING_ENABLE.

  • Defaults to: false
  • Supported values:
    • true or 1, to enable
    • false or 0, to disable

SMELTER_AHEAD_OF_TIME_PROCESSING_ENABLE

If enabled, the Smelter server will try to generate output frames/samples ahead of time if all inputs are available.

  • Defaults to: false
  • Supported values:
    • true or 1, to enable
    • false or 0, to disable

SMELTER_NEVER_DROP_OUTPUT_FRAMES

If enabled, the Smelter server will not drop frames/samples from output stream even if rendering or encoding is not fast enough to process it in real time.

  • Defaults to: false
  • Supported values:
    • true or 1, to enable
    • false or 0, to disable

SMELTER_RUN_LATE_SCHEDULED_EVENTS

Parts of the smelter API support a schedule_time_ms field to apply certain actions at a specific time. If enabled, the event will still be executed, even if it was scheduled too late.

  • Defaults to: false
  • Supported values:
    • true or 1, to enable
    • false or 0, to disable

SMELTER_REQUIRED_WGPU_FEATURES

List of WebGPU features to enable.

  • Defaults to:
UNIFORM_BUFFER_AND_STORAGE_TEXTURE_ARRAY_NON_UNIFORM_INDEXING,
SAMPLED_TEXTURE_AND_STORAGE_BUFFER_ARRAY_NON_UNIFORM_INDEXING
  • Supported values:
    • string containing comma-separated list of WebGPU features (see Rust WebGPU documentation for the list of available options)

SMELTER_INPUT_BUFFER_DURATION_MS

Duration (in ms) of an input buffer in milliseconds. New stream will not be processed until this buffer is filled.

  • Defaults to: 80 (about 5 frames in 60 fps)