Fix inline text inputs in ffmpeg jobs
Send subtitle files, text overlays and concat lists inline to ffmpeg jobs. Inputs written as { content } no longer fail with INVALID_PAYLOAD.
An ffmpeg job can take a small text file inline instead of a URL, written as { "content": "..." } or as a data: URL. Since at least 7 September 2026, those jobs were accepted and then failed straight away with INVALID_PAYLOAD. Nothing was downloaded or encoded.
They run now. The text is written to a file named after its input key, so the command can read it like any other file.
- Burn subtitles from inline ASS or SRT with
subtitles=captions.ass. - Draw text from a file with
drawtext=textfile=line1.txt, so apostrophes and colons never have to be escaped inside the filter. - Join clips from an inline list with
-f concat -i list.txt.
This applies wherever you submit jobs: the REST API, the SDK, the MCP submit_job tool and the n8n node. Inline inputs stay capped at 64 KB each. See the ffmpeg job reference for the input formats, and multi-file ffmpeg output for the release that introduced inline inputs.