feat(gateway): seedance 2.0 reference video input

apps/docs/content/features/video-generation.mdx

@@ -41,6 +41,7 @@ LLMGateway currently supports a focused subset of the OpenAI video API.
 | `last_frame`       | object  | no       | Optional ending frame when `image` is provided                                                                             |
 | `reference_images` | array   | no       | One to three provider-specific image inputs                                                                                |
 | `input_reference`  | object  | no       | Alias for one or more `reference_images`                                                                                   |
+| `reference_videos` | array   | no       | One to three reference video HTTPS URLs (Seedance 2.0 only, see below)                                                     |
 | `callback_url`     | string  | no       | LLMGateway extension for completion webhooks                                                                               |
 | `callback_secret`  | string  | no       | LLMGateway extension used to sign webhook deliveries                                                                       |
 
@@ -54,6 +55,33 @@ LLMGateway currently supports a focused subset of the OpenAI video API.
 
 Requests return `400` when the selected provider cannot serve the requested `size` or `seconds`. Seedance derives `aspect_ratio` from the requested `size` (16:9 for landscape, 9:16 for portrait).
 
+### Seedance 2.0 omni-reference
+
+Seedance 2.0 (`seedance-2-0`, `seedance-2-0-fast`) supports reference-guided video generation. You can supply reference images and reference videos in the same request:
+
+- `reference_images` (or `input_reference`) — one to three image inputs (HTTPS URLs or base64 data URLs)
+- `reference_videos` — one to three reference video **HTTPS URLs** (base64 data URLs are not supported for videos)
+
+Reference inputs cannot be combined with the first/last frame inputs (`image`, `last_frame`). Reference videos are only supported on Seedance 2.0 models.
+
+```bash
+curl -X POST "https://api.llmgateway.io/v1/videos" \
+  -H "Authorization: Bearer $LLM_GATEWAY_API_KEY" \
+  -H "Content-Type: application/json" \
+  -d '{
+    "model": "seedance-2-0",
+    "prompt": "The subject performs the choreography from the reference video",
+    "seconds": 5,
+    "size": "1280x720",
+    "reference_images": [
+      { "image_url": "https://example.com/subject.png" }
+    ],
+    "reference_videos": [
+      "https://example.com/reference-motion.mp4"
+    ]
+  }'
+```
+
 ### Not supported yet
 
 - multipart uploads

apps/gateway/src/videos/videos.spec.ts

@@ -171,6 +171,133 @@ describe("videos", () => {
 		);
 	});
 
+	test("/v1/videos rejects non-https reference videos", async () => {
+		await db.insert(tables.apiKey).values({
+			id: "token-id",
+			token: "real-token",
+			projectId: "project-id",
+			description: "Test API Key",
+			createdBy: "user-id",
+		});
+
+		const res = await app.request("/v1/videos", {
+			method: "POST",
+			headers: {
+				"Content-Type": "application/json",
+				Authorization: "Bearer real-token",
+			},
+			body: JSON.stringify({
+				model: "seedance-2-0",
+				prompt: "Reproduce the camera move from the reference clip",
+				size: "1280x720",
+				seconds: 5,
+				reference_videos: ["http://example.com/reference-motion.mp4"],
+			}),
+		});
+
+		expect(res.status).toBe(400);
+		const json = await res.json();
+		expect(JSON.stringify(json)).toContain("reference_videos");
+	});
+
+	test("/v1/videos rejects combining frames with reference videos", async () => {
+		await db.insert(tables.apiKey).values({
+			id: "token-id",
+			token: "real-token",
+			projectId: "project-id",
+			description: "Test API Key",
+			createdBy: "user-id",
+		});
+
+		const res = await app.request("/v1/videos", {
+			method: "POST",
+			headers: {
+				"Content-Type": "application/json",
+				Authorization: "Bearer real-token",
+			},
+			body: JSON.stringify({
+				model: "seedance-2-0",
+				prompt: "Blend these inputs",
+				size: "1280x720",
+				seconds: 5,
+				image: { image_url: "data:image/png;base64,aGVsbG8=" },
+				reference_videos: ["https://example.com/reference-motion.mp4"],
+			}),
+		});
+
+		expect(res.status).toBe(400);
+		const json = await res.json();
+		expect(JSON.stringify(json)).toContain("Frame inputs");
+	});
+
+	test("/v1/videos rejects reference videos on non-bytedance models", async () => {
+		await db.insert(tables.apiKey).values({
+			id: "token-id",
+			token: "real-token",
+			projectId: "project-id",
+			description: "Test API Key",
+			createdBy: "user-id",
+		});
+
+		await db.insert(tables.providerKey).values({
+			id: "provider-key-id",
+			token: "sk-test-key",
+			provider: "avalanche",
+			organizationId: "org-id",
+			baseUrl: mockServerUrl,
+		});
+
+		const res = await app.request("/v1/videos", {
+			method: "POST",
+			headers: {
+				"Content-Type": "application/json",
+				Authorization: "Bearer real-token",
+			},
+			body: JSON.stringify({
+				model: "avalanche/veo-3.1-fast-generate-preview",
+				prompt: "Reproduce this motion",
+				size: "1920x1080",
+				seconds: 8,
+				reference_videos: ["https://example.com/reference-motion.mp4"],
+			}),
+		});
+
+		expect(res.status).toBe(400);
+		const json = await res.json();
+		expect(JSON.stringify(json)).toContain(
+			"reference videos are currently only supported on bytedance",
+		);
+	});
+
+	test("/v1/videos restricts reference inputs to Seedance 2.0 models", async () => {
+		await db.insert(tables.apiKey).values({
+			id: "token-id",
+			token: "real-token",
+			projectId: "project-id",
+			description: "Test API Key",
+			createdBy: "user-id",
+		});
+
+		const res = await app.request("/v1/videos", {
+			method: "POST",
+			headers: {
+				"Content-Type": "application/json",
+				Authorization: "Bearer real-token",
+			},
+			body: JSON.stringify({
+				model: "bytedance/seedance-1-5-pro",
+				prompt: "Reproduce this motion",
+				size: "1280x720",
+				seconds: 5,
+				reference_videos: ["https://example.com/reference-motion.mp4"],
+			}),
+		});
+
+		expect(res.status).toBe(400);
+		const json = await res.json();
+		expect(JSON.stringify(json)).toContain("Seedance 2.0");
+	});
+
 	test("/v1/videos uses routing metrics to pick the best eligible provider", async () => {
 		const originalGoogleCloudProject = process.env.LLM_GOOGLE_CLOUD_PROJECT;
 		const originalRuntimeGoogleCloudProject = process.env.GOOGLE_CLOUD_PROJECT;