media/transcode

Transcode pipeline — FFmpeg format conversion and quality adjustment.

Category: media
Source: workflows/media/transcode.py

Input Schema

Field	Type	Default	Description
`audio_bitrate`	`string`	`"128k"`
`audio_codec`	`string`	`"aac"`
`codec`	`string`	`"libx264"`
`crf`	`integer`	`23`
`format`	`string`	`"mp4"`
`media_path`	`object`	required
`preset`	`string`	`"medium"`
`regenerate`	`object`	—	When set, this run is a regeneration. Workflows may read `direction` / `keep` / `extra_instructions` to modulate prompts; the engine persists `parent_run_id` and `parent_variant_index` as run lineage columns.
`resolution`	`object`	—
`subtitled_path`	`object`	—
`variants`	`integer`	`1`	Number of independent variant executions (1–10). When > 1, the engine runs the workflow N times with different sampling, producing N outputs.
`vertical_path`	`object`	—

Output Schema

No schema defined.

Task Pipeline

transcode_video

Task	Description
`transcode_video`	Transcode video to target format/codec/quality.

Run-spec example

Save the YAML below as my-run.yaml, edit the values, and run with the CLI or POST it to the API. Required fields are uncommented; optional knobs are documented above the input: block — copy any line under input: and uncomment to set.

workflow: media/transcode

# Optional fields — copy any line(s) under `input:` and uncomment to set:
#   audio_bitrate: 128k
#
#   audio_codec: aac
#
#   codec: libx264
#
#   crf: 23
#
#   format: mp4
#
#   preset: medium
#
#   resolution: null
#
#   subtitled_path: null
#
#   vertical_path: null
#

input:
  media_path: ""

Run it locally:

fab-workflow --from-file my-run.yaml

Or submit over the wire — the same file is the request body:

curl -X POST 'https://gofabric.dev/v1/workflows/runs?name=media/transcode' \
  -H 'Authorization: Bearer fab_xxx' \
  -H 'content-type: application/yaml' \
  --data-binary @my-run.yaml

Every workflow also accepts the universal WorkflowInput fields — variants (1–10 fan-out) and regenerate (creative-direction hints with run lineage). See Run-specs (YAML / TOML / JSON) for the full top-level shape (metadata, priority, bundle, parent, etc.).

Warnings

Last user task transcode_video has no Pydantic return type — workflow output schema is null. Declare a WorkflowOutput subclass and pass it to Flow(output=…) for a strict contract.