fix: proxy videos through Space same-origin to avoid cross-origin <video> blocks

app.py

@@ -79,6 +79,17 @@ print(f"[mbench-ann] loaded {len(TASKS)} tasks × {len(MODELS)} models = {len(PO
 
 
 def _video_url(model: str, task_id: str) -> str:
+    """Same-origin proxy URL served by this Space (see /video route below).
+
+    We proxy the mp4 through the Space to avoid cross-origin issues that cause
+    some browsers to refuse playing HF's xet CDN as a <video> source even
+    though the CDN itself is reachable.
+    """
+    return f"/video/{model}/{task_id}.mp4"
+
+
+def _hf_video_url(model: str, task_id: str) -> str:
+    """Real HF dataset URL — used only inside the proxy route."""
     return hf_hub_url(
         DATASET_REPO,
         filename=f"MBench-V/{model}/videos/{task_id}.mp4",
@@ -462,4 +473,63 @@ with gr.Blocks(title="MBench-V 标注", theme=gr.themes.Soft(),
 
 
 if __name__ == "__main__":
-    demo.queue(default_concurrency_limit=16).launch()
+    # -----------------------------------------------------------------------
+    # Same-origin video proxy route
+    # -----------------------------------------------------------------------
+    # Many browsers refuse to play cross-origin third-party-cookie-tainted
+    # <video> sources (hf.space iframe → xet CDN). We dodge this by streaming
+    # the mp4 through this Space's own FastAPI app so the browser sees the
+    # video on the same origin as the page.
+    import httpx
+    import uvicorn
+    from fastapi import FastAPI, HTTPException, Request
+    from fastapi.responses import StreamingResponse
+
+    fastapi_app = FastAPI()
+    _video_client = httpx.AsyncClient(timeout=30.0, follow_redirects=True)
+
+    @fastapi_app.api_route(
+        "/video/{model}/{task_id}.mp4",
+        methods=["GET", "HEAD"],
+        include_in_schema=False,
+    )
+    async def _proxy_video(model: str, task_id: str, request: Request):
+        if model not in MODELS or task_id not in TASK_BY_ID:
+            raise HTTPException(404, "unknown (model, task_id)")
+        upstream = _hf_video_url(model, task_id)
+        req_headers = {}
+        if (rng := request.headers.get("range")):
+            req_headers["range"] = rng
+        try:
+            upstream_resp = await _video_client.send(
+                _video_client.build_request("GET", upstream, headers=req_headers),
+                stream=True,
+            )
+        except Exception as e:
+            raise HTTPException(502, f"upstream fetch failed: {e}")
+        passthrough_headers = {}
+        for h in ("content-type", "content-length", "accept-ranges",
+                  "content-range", "etag", "last-modified"):
+            if h in upstream_resp.headers:
+                passthrough_headers[h] = upstream_resp.headers[h]
+        passthrough_headers.setdefault("content-type", "video/mp4")
+        passthrough_headers["cache-control"] = "public, max-age=300"
+
+        async def _body():
+            try:
+                async for chunk in upstream_resp.aiter_bytes(chunk_size=65536):
+                    yield chunk
+            finally:
+                await upstream_resp.aclose()
+
+        return StreamingResponse(
+            _body(),
+            status_code=upstream_resp.status_code,
+            headers=passthrough_headers,
+        )
+
+    demo.queue(default_concurrency_limit=16)
+    fastapi_app = gr.mount_gradio_app(fastapi_app, demo, path="/")
+    print("[mbench-ann] mounted Gradio at '/' with /video proxy route")
+    uvicorn.run(fastapi_app, host="0.0.0.0", port=7860)
+

requirements.txt

@@ -1,2 +1,4 @@
 gradio==5.9.1
 huggingface_hub>=0.26,<0.30
+httpx>=0.27
+uvicorn>=0.30