Platform Nodes

Pre-built nodes for common platform tasks.

Platform nodes are templates that bundle the correct Nix packages, input/output types, and command structure for widely-used CLI tools. You specify parameters; the template handles the rest.

Available platform nodes

Node	Tool	Description
ffmpeg.*	ffmpeg	Video and audio processing.
pandoc.*	pandoc	Document format conversion.
imagemagick.*	imagemagick	Image manipulation.
yt-dlp.*	yt-dlp	Media download from supported sites.

ffmpeg

Video and audio processing. Nix package: ffmpeg.

flow.yaml

transcode-video:
  type: deterministic
  op: cli.run
  template: ffmpeg.transcode
  params:
    command: >
      ffmpeg -i {{ input_path }} -vf scale={{ width }}:{{ height }}
      -c:v libx264 -preset {{ preset }} artifacts/{{ output_name }}.mp4
    nix: { packages: [ffmpeg] }
  inputs:
    config: { type: Record }
  outputs:
    result: { type: Record }

Template	What it does
ffmpeg.transcode	Convert between video formats.
ffmpeg.extract_audio	Extract audio track from video.
ffmpeg.thumbnail	Generate thumbnail at a timestamp.
ffmpeg.concat	Concatenate multiple media files.

pandoc

Document conversion. Nix packages: pandoc, texlive.combined.scheme-small.

convert-docs:
  type: deterministic
  op: cli.run
  template: pandoc.convert
  params:
    command: >
      pandoc {{ input_path }} -f {{ from_format }}
      -t {{ to_format }} -o artifacts/{{ output_name }}.{{ to_format }}
    nix: { packages: [pandoc, texlive.combined.scheme-small] }
  inputs:
    config: { type: Record }
  outputs:
    result: { type: Record }

Template	What it does
pandoc.convert	Convert between document formats.
pandoc.pdf	Render to PDF via LaTeX.
pandoc.html	Render to standalone HTML.

imagemagick

Image manipulation. Nix package: imagemagick.

resize-batch:
  type: deterministic
  op: cli.run
  template: imagemagick.resize
  params:
    command: >
      convert {{ input_path }} -resize {{ dimensions }}
      -quality {{ quality }} artifacts/{{ output_name }}
    nix: { packages: [imagemagick] }
  inputs:
    images: { type: Table }
  outputs:
    results: { type: Table }

Template	What it does
imagemagick.resize	Resize images to target dimensions.
imagemagick.convert	Convert between image formats.
imagemagick.composite	Overlay images (watermark, badge).
imagemagick.annotate	Add text to images.

yt-dlp

Media download from supported sites. Nix package: yt-dlp.

download-media:
  type: source
  op: cli.run
  template: yt-dlp.download
  params:
    command: >
      yt-dlp -f "{{ format }}" -o "artifacts/%(title)s.%(ext)s" {{ url }}
    nix: { packages: [yt-dlp] }
  inputs:
    request: { type: Record }
  outputs:
    result: { type: Record }

Template	What it does
yt-dlp.download	Download video in specified format.
yt-dlp.audio	Extract audio only (mp3, opus, wav).
yt-dlp.metadata	Fetch metadata without downloading.
yt-dlp.playlist	Download all items in a playlist.

Platform nodes vs. custom CLI nodes

Use a platform node when a template exists for your task. Templates guarantee correct package versions, handle common edge cases, and produce consistent output schemas.

Use a custom CLI node (op: cli.run without a template) when:

• No template covers your tool or workflow.
• You need to chain multiple tools in a single command.
• You want full control over the command string and output parsing.

Platform nodes are just CLI nodes with pre-configured defaults. You can always override any field in the template by setting it explicitly in params.

Versioning

Platform node templates are versioned with Radhflow itself. When you upgrade Radhflow, template defaults may change (e.g., new ffmpeg flags for better compression). Existing pipelines that pin nix.nixpkgs are unaffected — the underlying tool versions stay the same.

To check which version of a template you’re using:

rf inspect --node transcode-video

This shows the resolved template, including all default values.