Update app.py

add endpoint para unir narração com fundo musical

app.py

@@ -247,7 +247,80 @@ async def get_duration_from_url(payload: Dict):
         # Este bloco é executado sempre, mesmo se ocorrerem erros
         if os.path.exists(temp_audio_path):
             os.remove(temp_audio_path)
-            print(f"--- CLEANUP: Removed temporary probe file {temp_audio_path} ---")            
+            print(f"--- CLEANUP: Removed temporary probe file {temp_audio_path} ---")   
+
+# ==============================================================================
+# ENDPOINT PARA MIXAR NARRAÇÃO E MÚSICA DE FUNDO
+# ==============================================================================
+
+@app.post("/mix-audio-tracks/")
+async def mix_audio_tracks(
+    narration_file: UploadFile = File(...),
+    music_file: UploadFile = File(...),
+    music_volume: float = Form(0.3)
+):
+    """
+    Mixes a narration track with a background music track.
+
+    It lowers the volume of the music track and mixes it with the narration,
+    ensuring the final track's duration matches the narration.
+
+    Args:
+        narration_file (UploadFile): The main narration audio file.
+        music_file (UploadFile): The background music audio file.
+        music_volume (float): The desired volume for the background music (0.0 to 1.0).
+
+    Returns:
+        FileResponse: The final mixed audio file.
+    """
+    # Validação de entrada
+    if not (0.0 <= music_volume <= 1.0):
+        raise HTTPException(status_code=400, detail="music_volume must be between 0.0 and 1.0")
+
+    # Setup do ambiente temporário
+    unique_id = str(uuid.uuid4())
+    temp_processing_dir = os.path.join(TEMP_DIR, unique_id)
+    os.makedirs(temp_processing_dir)
+    
+    narration_path = os.path.join(temp_processing_dir, "narration.mp3")
+    music_path = os.path.join(temp_processing_dir, "music.mp3")
+    mixed_audio_path = os.path.join(temp_processing_dir, "mixed_audio.mp3")
+
+    try:
+        # Salva os arquivos recebidos
+        with open(narration_path, "wb") as buffer:
+            shutil.copyfileobj(narration_file.file, buffer)
+        with open(music_path, "wb") as buffer:
+            shutil.copyfileobj(music_file.file, buffer)
+        
+        # Constrói o comando FFmpeg com o filtro 'amix'
+        # [0:a] -> primeiro input (narração)
+        # [1:a] -> segundo input (música)
+        # volume=... -> aplica o volume apenas no segundo input
+        # duration=first -> a mixagem termina quando o primeiro input (narração) acabar
+        command = (
+            f"ffmpeg -i {shlex.quote(narration_path)} -i {shlex.quote(music_path)} "
+            f"-filter_complex \"[1:a]volume={music_volume}[bg];[0:a][bg]amix=inputs=2:duration=first\" "
+            f"-y {shlex.quote(mixed_audio_path)}"
+        )
+
+        # Executa o comando
+        await run_subprocess(command)
+        print("SUCCESS: Narration and music mixed successfully.")
+
+        # Retorna o arquivo final e agenda a limpeza
+        cleanup_task = BackgroundTask(cleanup_directory, directory_path=temp_processing_dir)
+        return FileResponse(
+            path=mixed_audio_path,
+            filename="mixed_audio.mp3",
+            media_type="audio/mpeg",
+            background=cleanup_task
+        )
+
+    except Exception as e:
+        cleanup_directory(directory_path=temp_processing_dir)
+        raise HTTPException(status_code=500, detail=f"An internal server error occurred: {str(e)}")
+            
 
 # ==============================================================================
 # ENDPOINT "TUDO-EM-UM" OTIMIZADO (VERSÃO FINAL)