transcode_for_browser: write H.264 into same upload dir so Gradio file server allows it

app.py

@@ -175,14 +175,13 @@ def _transcode_for_browser(video_path: str) -> str:
         if video_streams and video_streams[0].get("codec_name") == "h264":
             print(f"[transcode_for_browser] already H.264, skipping")
             return video_path
-        # Write to a fresh gradio-served temp dir so Gradio re-probes from scratch
-        # and never sees the H.265 source for this returned value.
-        import hashlib as _hashlib, os as _os
-        basename  = _os.path.basename(video_path)
-        tag       = _hashlib.sha256((video_path + "_h264").encode()).hexdigest()
-        out_dir   = f"/tmp/gradio/{tag}"
-        _os.makedirs(out_dir, exist_ok=True)
-        out_path  = _os.path.join(out_dir, basename)
+        # Write the H.264 output into the SAME directory as the original upload.
+        # Gradio's file server only allows paths under dirs it registered — the
+        # upload dir is already allowed, so a sibling file there will serve fine.
+        import os as _os
+        upload_dir = _os.path.dirname(video_path)
+        stem       = _os.path.splitext(_os.path.basename(video_path))[0]
+        out_path   = _os.path.join(upload_dir, stem + "_h264.mp4")
         kwargs = dict(
             vcodec="libx264", preset="fast", crf=18,
             pix_fmt="yuv420p", movflags="+faststart",