fix: handle broken pipe and filter graph failures in playback loop

Co-authored-by: aider (gemini/gemini-3.1-pro-preview) <aider@aider.chat>

main.py

@@ -26,6 +26,18 @@ def playback_thread(file_path, state):
     stream = container.streams.audio[0]
     resampler = av.AudioResampler(format='s16', layout='stereo', rate=48000)
     
+    def build_graph(template_frame):
+        graph = av.filter.Graph()
+        src = graph.add_abuffer(template=template_frame)
+        loudnorm = graph.add("loudnorm", "I=-16:TP=-1.5:LRA=11")
+        sink = graph.add("abuffersink")
+        src.link_to(loudnorm)
+        loudnorm.link_to(sink)
+        graph.configure()
+        return graph
+
+    graph = None
+    
     with open(fifo_path, 'wb') as fifo:
         iterator = container.decode(stream)
         while state.running:
@@ -41,6 +53,7 @@ def playback_thread(file_path, state):
                 with state.lock:
                     state.seek_request = None
                 iterator = container.decode(stream)
+                graph = None  # Reset filter graph on seek
                 continue
                 
             if paused:
@@ -57,17 +70,44 @@ def playback_thread(file_path, state):
             with state.lock:
                 state.time_pos = float(frame.pts * stream.time_base)
                 
-            resampled_frames = resampler.resample(frame)
-            for r_frame in resampled_frames:
-                arr = r_frame.to_ndarray()
+            if graph is None:
+                try:
+                    graph = build_graph(frame)
+                except Exception as e:
+                    print(f"Filter graph error: {e}", file=sys.stderr)
+                    graph = "FAILED"
                     
-                # Apply volume
-                if vol != 100.0:
-                    multiplier = max(0.0, vol / 100.0)
-                    arr = arr.astype(np.float32) * multiplier
-                    arr = np.clip(arr, -32768, 32767).astype(np.int16)
+            if graph == "FAILED":
+                frames_to_process = [frame]
+            else:
+                try:
+                    graph.push(frame)
+                except av.AVError:
+                    continue
                     
-                fifo.write(arr.tobytes())
+                frames_to_process = []
+                while True:
+                    try:
+                        frames_to_process.append(graph.pull())
+                    except (av.AVError, BlockingIOError):
+                        break
+                        
+            for filtered_frame in frames_to_process:
+                resampled_frames = resampler.resample(filtered_frame)
+                for r_frame in resampled_frames:
+                    arr = r_frame.to_ndarray()
+                    
+                    # Apply volume
+                    if vol != 100.0:
+                        multiplier = max(0.0, vol / 100.0)
+                        arr = arr.astype(np.float32) * multiplier
+                        arr = np.clip(arr, -32768, 32767).astype(np.int16)
+                        
+                    try:
+                        fifo.write(arr.tobytes())
+                    except BrokenPipeError:
+                        state.running = False
+                        return
 
 def handle_ipc_client(conn, state):
     buffer = ""
@@ -168,6 +208,9 @@ def main():
     
     try:
         playback_thread(args.file, state)
+        # Keep the main thread alive until Navidrome explicitly sends 'quit'
+        while state.running:
+            time.sleep(0.1)
     except KeyboardInterrupt:
         pass
     finally: