Gap 13: BWF/INFO metadata cho WAV export — wav_bwf.patch_bwf_metadata chen bext + LIST/INFO (INAM/IART/ISRC/ICMT) truoc data chunk, giu nguyen PCM bits; render_project(metadata=) + RenderRequest.metadata + cloud render task; ExportModal Title/Artist/ISRC; test_66 (178 passed)

app/core/render_engine.py

@@ -839,7 +839,9 @@ class PythonRenderEngine:
     def render_project(self, project_json: dict, output_filepath: str,
                        bit_depth: int = 32, out_sample_rate: int = 0,
                        dither: bool = False, normalize: bool = False,
-                       normalize_target: str = "-1dbtp"):
+                       normalize_target: str = "-1dbtp",
+                       metadata: dict = None):
+        # Gap 13: BWF/INFO metadata — tham số phụ, không đổi hành vi cũ khi None.
         with RENDER_LOCK:
             bpm = project_json["metadata"]["bpm"]
             time_sig_num = project_json["metadata"].get("time_signature_numerator", 4)
@@ -963,4 +965,12 @@ class PythonRenderEngine:
                          out_sr, subtype="PCM_24")
             else:
                 sf.write(output_filepath, master_buffer.T, out_sr, subtype="FLOAT")
+            # Gap 13: BWF/INFO chunks (bext + LIST/INFO title/artist/ISRC) —
+            # chen sau khi ghi PCM, loi metadata khong lam hong file audio.
+            if metadata:
+                try:
+                    from app.core.wav_bwf import patch_bwf_metadata
+                    patch_bwf_metadata(output_filepath, metadata)
+                except Exception as e:
+                    logger.warning("[RenderEngine] BWF metadata skipped: %s", e)
             return output_filepath

app/core/wav_bwf.py

@@ -0,0 +1,88 @@
+"""Gap 13: BWF/INFO metadata chunks cho WAV export (EBU Tech 3285 + RIFF INFO).
+
+sf.write chi ghi fmt/data — ham nay chen bext (602 bytes fixed + coding history)
+va LIST/INFO (INAM title, IART artist, ISRC, ICMT comment) ngay truoc data chunk
+roi ghi lai file. Pure stdlib (struct/datetime).
+"""
+import datetime
+import struct
+
+_BEXT_FIXED = 602
+
+
+def _pad(text, length):
+    raw = text.encode("utf-8", errors="replace")
+    return (raw[:length] + b"\x00" * length)[:length]
+
+
+def _chunk(fourcc, payload):
+    pad = b"\x00" if len(payload) % 2 else b""
+    return fourcc + struct.pack("<I", len(payload)) + payload + pad
+
+
+def _info_sub(fourcc, text):
+    if not text:
+        return b""
+    return _chunk(fourcc, _pad(text, len(text.encode("utf-8", errors="replace")) + 1))
+
+
+def _bext(md, now):
+    fixed = bytearray(_BEXT_FIXED)
+    fixed[0:256] = _pad(md.get("description", ""), 256)
+    fixed[256:288] = _pad(md.get("originator", "SonicForgeStudio"), 32)
+    fixed[288:320] = _pad(md.get("originator_reference", ""), 32)
+    fixed[320:330] = _pad((md.get("date") or now.strftime("%Y-%m-%d")), 10)
+    fixed[330:338] = _pad((md.get("time") or now.strftime("%H:%M:%S")), 8)
+    struct.pack_into("<II", fixed, 338, 0, 0)          # time reference low/high
+    struct.pack_into("<H", fixed, 346, 1)              # version = 1
+    fixed[348:412] = bytes(64)                         # UMID (zero)
+    struct.pack_into("<hhhhh", fixed, 412, -32768, -32768, -32768, -32768, -32768)  # loudness: 0x8000 = unset
+    fixed[422:602] = bytes(180)                        # reserved
+    coding = md.get("coding_history", "").encode("utf-8", errors="replace")
+    return bytes(fixed) + coding
+
+
+def patch_bwf_metadata(path, metadata=None):
+    """Chen bext + LIST/INFO vao WAV tai path (rewrite in-place, giu nguyen PCM bits).
+
+    metadata keys: title, artist, isrc, comment, description, originator,
+    originator_reference, date (YYYY-MM-DD), time (HH:MM:SS), coding_history.
+    Bo qua neu file khong phai RIFF/WAVE hop le hoac metadata rong.
+    """
+    if not metadata:
+        return
+    md = {k: (v or "").strip() for k, v in metadata.items() if v}
+    if not md:
+        return
+    with open(path, "rb") as f:
+        data = f.read()
+    if len(data) < 12 or data[:4] != b"RIFF" or data[8:12] != b"WAVE":
+        return
+
+    off = 12
+    pre = b""
+    data_chunk = None
+    while off + 8 <= len(data):
+        cid = data[off:off + 4]
+        size = struct.unpack("<I", data[off + 4:off + 8])[0]
+        body = data[off + 8:off + 8 + size]
+        if cid == b"data":
+            data_chunk = (cid, size, body)
+            break
+        pre += _chunk(cid, body)
+        off += 8 + size + (size % 2)
+    if data_chunk is None:
+        return
+
+    now = datetime.datetime.now()
+    info_payload = b"INFO" + b"".join([
+        _info_sub(b"INAM", md.get("title", "")),
+        _info_sub(b"IART", md.get("artist", "")),
+        _info_sub(b"ISRC", md.get("isrc", "")),
+        _info_sub(b"ICMT", md.get("comment", "")),
+    ])
+    extra = _chunk(b"bext", _bext(md, now)) + _chunk(b"LIST", info_payload)
+    new_data = data[:12] + pre + extra + _chunk(data_chunk[0], data_chunk[2])
+    new_data = new_data[:4] + struct.pack("<I", len(new_data) - 8) + new_data[8:]
+    with open(path, "wb") as f:
+        f.write(new_data)