diff --git a/packages/producer/src/regression-harness-distributed.ts b/packages/producer/src/regression-harness-distributed.ts
index 6fe3f6582..c62435b23 100644
--- a/packages/producer/src/regression-harness-distributed.ts
+++ b/packages/producer/src/regression-harness-distributed.ts
@@ -117,6 +117,12 @@ export interface RunDistributedSimulatedInput {
/** From the fixture's renderConfig — must pass `checkDistributedSupport`. */
fps: 24 | 30 | 60;
format: "mp4" | "mov" | "png-sequence";
+ /**
+ * Codec for `format: "mp4"`. Defaults to `"h264"`; pass `"h265"` to
+ * exercise the libx265 closed-GOP path. Ignored for non-mp4 formats —
+ * `plan()` throws if codec is passed with a non-mp4 format.
+ */
+ codec?: "h264" | "h265";
/** Optional chunkSize override; defaults to the plan's 240. */
chunkSize?: number;
/** Optional maxParallelChunks override; defaults to the plan's 16. */
@@ -147,23 +153,38 @@ export async function runDistributedSimulatedRender(
mkdirSync(planDir, { recursive: true });
mkdirSync(chunksDir, { recursive: true });
- // Step A: plan.
+ // Step A: plan. `codec` is only forwarded when the format actually
+ // accepts it — `plan()` throws if codec is set for a non-mp4 format,
+ // and a caller passing `format: "mov", codec: undefined` would still
+ // surface that field in the resulting object. We omit it conditionally
+ // to keep the off-path planDir identical to pre-codec-knob output.
const planResult = await plan(
input.projectDir,
- {
- fps: input.fps,
- // Required-by-type but overridden by the composition's own attrs;
- // see docstring above. Any positive integer works.
- width: 1920,
- height: 1080,
- format: input.format,
- chunkSize: input.chunkSize,
- maxParallelChunks: input.maxParallelChunks,
- // Force the SDR path explicitly — `auto` would still resolve to
- // force-sdr in distributed mode, but pinning it here keeps the
- // harness's behavior independent of any future auto-detect changes.
- hdrMode: "force-sdr",
- },
+ input.format === "mp4"
+ ? {
+ fps: input.fps,
+ width: 1920,
+ height: 1080,
+ format: "mp4",
+ codec: input.codec,
+ chunkSize: input.chunkSize,
+ maxParallelChunks: input.maxParallelChunks,
+ hdrMode: "force-sdr",
+ }
+ : {
+ fps: input.fps,
+ // Required-by-type but overridden by the composition's own attrs;
+ // see docstring above. Any positive integer works.
+ width: 1920,
+ height: 1080,
+ format: input.format,
+ chunkSize: input.chunkSize,
+ maxParallelChunks: input.maxParallelChunks,
+ // Force the SDR path explicitly — `auto` would still resolve to
+ // force-sdr in distributed mode, but pinning it here keeps the
+ // harness's behavior independent of any future auto-detect changes.
+ hdrMode: "force-sdr",
+ },
planDir,
);
diff --git a/packages/producer/src/regression-harness.ts b/packages/producer/src/regression-harness.ts
index 296b20c53..776d14145 100644
--- a/packages/producer/src/regression-harness.ts
+++ b/packages/producer/src/regression-harness.ts
@@ -56,6 +56,17 @@ type TestMetadata = {
* time; the in-process renderer accepts it.
*/
format?: "mp4" | "webm" | "mov" | "png-sequence";
+ /**
+ * Codec selection for `format: "mp4"`, forwarded to
+ * `DistributedRenderConfig.codec`. The in-process renderer doesn't take
+ * a codec hint — for the baseline it always picks the format's default
+ * (h264 for mp4 SDR), so `codec: "h265"` is exercised exclusively in
+ * `--mode=distributed-simulated`. The PSNR comparison against the
+ * baseline therefore measures "h265 chunked + concat" ≈ "h264 single-
+ * pass" rather than byte equality. Fixtures asserting a tighter
+ * contract should explicitly pin a higher `minPsnr`.
+ */
+ codec?: "h264" | "h265";
workers?: number; // Optional: auto-calculates if omitted
/** Force HDR in the harness; omitted/false preserves historical SDR-only test behavior. */
hdr?: boolean;
@@ -250,6 +261,25 @@ function validateMetadata(meta: unknown): TestMetadata {
"meta.json: 'renderConfig.format' must be 'mp4', 'webm', 'mov', or 'png-sequence' (or omit for mp4)",
);
}
+ if (rc.codec !== undefined && rc.codec !== "h264" && rc.codec !== "h265") {
+ throw new Error(
+ "meta.json: 'renderConfig.codec' must be 'h264' or 'h265' (or omit for the format's default)",
+ );
+ }
+ // Normalize the implicit default before comparing so a fixture that
+ // omits `format` (which defaults to "mp4" everywhere downstream) doesn't
+ // get accidentally treated as "format is missing, so codec is illegal."
+ // The previous formulation `rc.format !== undefined && rc.format !== "mp4"`
+ // worked but relied on the reader knowing the default; this reads the
+ // intent more directly.
+ const effectiveFormat = (rc.format as string | undefined) ?? "mp4";
+ if (rc.codec !== undefined && effectiveFormat !== "mp4") {
+ throw new Error(
+ `meta.json: 'renderConfig.codec' is only valid for format='mp4' (got format=${JSON.stringify(
+ rc.format,
+ )})`,
+ );
+ }
if (rc.workers !== undefined) {
if (typeof rc.workers !== "number" || rc.workers < 1) {
throw new Error("meta.json: 'renderConfig.workers' must be >= 1 (or omit to auto-calculate)");
@@ -822,6 +852,7 @@ async function runTestSuite(
renderedOutputPath,
fps: fpsNum,
format: outputFormat as "mp4" | "mov" | "png-sequence",
+ codec: suite.meta.renderConfig.codec,
chunkSize: suite.meta.renderConfig.chunkSize,
maxParallelChunks: suite.meta.renderConfig.maxParallelChunks,
variables: suite.meta.renderConfig.variables,
diff --git a/packages/producer/tests/distributed/mp4-h265-sdr/meta.json b/packages/producer/tests/distributed/mp4-h265-sdr/meta.json
new file mode 100644
index 000000000..6fa3ddfc5
--- /dev/null
+++ b/packages/producer/tests/distributed/mp4-h265-sdr/meta.json
@@ -0,0 +1,18 @@
+{
+ "name": "Distributed: mp4 H.265 SDR",
+ "description": "60-frame composition (2s @ 30fps) with text, a crossfade transition, and a small rotating SVG icon. renderConfig.format=mp4 + codec=h265 routes the distributed pipeline through libx265 with closed-GOP keyint params (min-keyint=N:scenecut=0:open-gop=0:repeat-headers=1). The in-process baseline is rendered as h264 because the in-process renderer doesn't expose a codec hint — the harness's PSNR comparison therefore measures 'libx265 chunked + concat' against 'libx264 single-pass', catching gross codec failures while accepting normal cross-codec PSNR drift (~30-35 dB at standard quality).",
+ "tags": ["distributed", "mp4", "h265", "hevc", "sdr"],
+
+ "minPsnr": 30,
+ "maxFrameFailures": 0,
+
+ "minAudioCorrelation": 0.9,
+ "maxAudioLagWindows": 120,
+
+ "renderConfig": {
+ "fps": 30,
+ "format": "mp4",
+ "codec": "h265",
+ "chunkSize": 15
+ }
+}
diff --git a/packages/producer/tests/distributed/mp4-h265-sdr/output/compiled.html b/packages/producer/tests/distributed/mp4-h265-sdr/output/compiled.html
new file mode 100644
index 000000000..e3a9ca8f1
--- /dev/null
+++ b/packages/producer/tests/distributed/mp4-h265-sdr/output/compiled.html
@@ -0,0 +1,121 @@
+
+
+
+
+
+ mp4 H.265 SDR distributed fixture
+
+
+
+
+
+
+
+
+
diff --git a/packages/producer/tests/distributed/mp4-h265-sdr/output/output.mp4 b/packages/producer/tests/distributed/mp4-h265-sdr/output/output.mp4
new file mode 100644
index 000000000..0312c24cf
--- /dev/null
+++ b/packages/producer/tests/distributed/mp4-h265-sdr/output/output.mp4
@@ -0,0 +1,3 @@
+version https://git-lfs.github.com/spec/v1
+oid sha256:c62e51a616e24c4ba16504a8508bafa58866bd3dabc68cbf32076a49eabb53bd
+size 59699
diff --git a/packages/producer/tests/distributed/mp4-h265-sdr/src/index.html b/packages/producer/tests/distributed/mp4-h265-sdr/src/index.html
new file mode 100644
index 000000000..ce638a515
--- /dev/null
+++ b/packages/producer/tests/distributed/mp4-h265-sdr/src/index.html
@@ -0,0 +1,115 @@
+
+
+
+
+
+ mp4 H.265 SDR distributed fixture
+
+
+
+
+
+
+
+
+