Auto-Batching

FFmpeg’s filter_complex argument has platform-specific length limits:

With many text overlays or complex animation combinations, the generated filter graph can exceed these limits — causing FFmpeg to fail with a cryptic argument-too-long error.

simple-ffmpegjs handles this automatically. It detects oversized filter graphs and splits text overlay passes into multiple sequential renders with intermediate files. No configuration required.

When it activates

Batching kicks in for:

• Typewriter animations with long text
• Many simultaneous text overlays (default threshold: 75 filter nodes per pass)
• Complex animation combinations (e.g. multiple pop-bounce or pulse clips)

With verbose: true in export options, you’ll see a log message when batching activates.

Tuning

For very complex projects, you can adjust the thresholds:

await project.export({
  outputPath: "./output.mp4",
  textMaxNodesPerPass: 30,         // default: 75
  intermediateVideoCodec: "libx264", // default
  intermediateCrf: 18,             // default (high quality)
  intermediatePreset: "veryfast",  // default (fast encoding for intermediate files)
});