diff --git a/packages/engine/src/services/chunkEncoder.test.ts b/packages/engine/src/services/chunkEncoder.test.ts
index d97c3939e..4014afd38 100644
--- a/packages/engine/src/services/chunkEncoder.test.ts
+++ b/packages/engine/src/services/chunkEncoder.test.ts
@@ -154,6 +154,11 @@ describe("encodeFramesFromDir ffmpegEncodeTimeout", () => {
     expect(result.error).toContain("FFmpeg exited with code 143");
     expect(result.error).toContain("terminated by timeout");
     expect(result.error).toContain(encodeTimeoutMessage(1000));
+    // Regression: the timeout message used to just state what happened, leaving
+    // the user to independently discover FFMPEG_ENCODE_TIMEOUT_MS and
+    // PRODUCER_ENABLE_CHUNKED_ENCODE (both already existed) on their own.
+    expect(result.error).toContain("FFMPEG_ENCODE_TIMEOUT_MS");
+    expect(result.error).toContain("PRODUCER_ENABLE_CHUNKED_ENCODE");
   });
 
   it("keeps non-timeout ffmpeg failures unchanged", async () => {
diff --git a/packages/engine/src/services/chunkEncoder.ts b/packages/engine/src/services/chunkEncoder.ts
index 060e69aa7..44f3e68ab 100644
--- a/packages/engine/src/services/chunkEncoder.ts
+++ b/packages/engine/src/services/chunkEncoder.ts
@@ -44,7 +44,17 @@ export interface EncoderPreset {
 
 function appendEncodeTimeoutMessage(error: string, timedOut: boolean, timeoutMs: number): string {
   if (!timedOut) return error;
-  return `${error}\nFFmpeg killed after exceeding ffmpegEncodeTimeout (${timeoutMs} ms)`;
+  // Two independent reports of this exact timeout, both resolved by env vars
+  // that already exist but aren't named anywhere the user would see them at
+  // the point of failure — they had to go find FFMPEG_ENCODE_TIMEOUT_MS and
+  // PRODUCER_ENABLE_CHUNKED_ENCODE themselves. Name both here instead of
+  // just stating what happened.
+  return (
+    `${error}\nFFmpeg killed after exceeding ffmpegEncodeTimeout (${timeoutMs} ms). ` +
+    "Long or high-frame-count renders may need more time: set FFMPEG_ENCODE_TIMEOUT_MS " +
+    "to a higher value (ms), or set PRODUCER_ENABLE_CHUNKED_ENCODE=true to encode in " +
+    "smaller chunks instead of one long-running ffmpeg process."
+  );
 }
 
 function isAacSidecar(audioPath: string): boolean {