Nexrender @nexrender/action-encode failing: "Could not get frame filename number 2 from pattern" when generating poster image

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I'm running a Nexrender job using a Node.js SQS consumer setup. The render completes successfully, but the postrender step fails when attempting to generate a poster JPG with FFmpeg from the output.mp4 (the output.mp4 uploads successfully).

LoUjWD987PpZbJakXLcXr] frame= 1 fps=0.0 q=2.2 size=N/A time=00:00:00.04 bitrate=N/A speed=1.96x [LoUjWD987PpZbJakXLcXr] [image2 @ ...] Could not get frame filename number 2 from pattern 'C:\nexrender\work\LoUjWD987PpZbJakXLcXr\poster.jpg'. Use '-frames:v 1' for a single image, or '-update' option, or use a pattern such as %03d within the filename. av_interleaved_write_frame(): Invalid argument ... ❌ Render failed: Error loading postrender module @nexrender/action-encode: Error: Error in action-encode module (ffmpeg) code : 1

Here’s a simplified version of the Node.js consumer for context:

const { Consumer } = require("sqs-consumer");
const { render } = require("@nexrender/core");
const { SQSClient } = require("@aws-sdk/client-sqs");
const sqsClient = new SQSClient({ region: process.env.AWS_REGION });
async function renderToMp4(jobData) {
 const result = await render(jobData, {
 workpath: "C:/nexrender/work",
 binary: "C:/Program Files/Adobe/Adobe After Effects 2024/Support Files/aerender.exe",
 logger: console
 });
 return result;
}

Here is an example of the json

{
 "projectId": "example-id",
 "template": {
 "src": "file:///D:/Nexrender/TestTextColorImageSet.aep",
 "composition": "1920x1080"
 },
 "assets": [
 { "type": "data", "layerName": "Color1", "property": "Effects.Fill.Color", "value": [1, 0, 0] },
 { "type": "data", "layerName": "Color2", "property": "Effects.Fill.Color", "value": [0.07, 0.65, 0.26] },
 { "type": "image", "layerName": "Image1", "src": "https://example-bucket.s3.amazonaws.com/projects/example/image1.jpg" },
 { "type": "image", "layerName": "Image2", "src": "https://example-bucket.s3.amazonaws.com/projects/example/image2.jpg" },
 { "type": "data", "layerName": "Text1", "property": "Source Text", "value": "test" },
 { "type": "data", "layerName": "Text2", "property": "Source Text", "value": "test 2" }
 ],
 "actions": {
 "postrender": [
 {
 "module": "@nexrender/action-encode",
 "preset": "mp4",
 "output": "output.mp4"
 },
 {
 "module": "@nexrender/action-upload",
 "input": "output.mp4",
 "provider": "s3",
 "params": {
 "bucket": "example-bucket",
 "region": "us-east-1",
 "key": "projects/example/output.mp4",
 "contentType": "video/mp4"
 }
 },
 {
 "module": "@nexrender/action-encode",
 "input": "output.mp4",
 "output": "poster.jpg",
 "preset": {
 "ffmpeg": "-i {input} -ss 4 -frames:v 1 -q:v 2 -update 1 {output}"
 }
 },
 {
 "module": "@nexrender/action-upload",
 "input": "poster.jpg",
 "provider": "s3",
 "params": {
 "bucket": "example-bucket",
 "region": "us-east-1",
 "key": "projects/example/poster.jpg",
 "contentType": "image/jpeg"
 }
 }
 ]
 }
}

Any help would be fantastic