fix: removed some errors and made sure that same filenames but different files do not break

extract.py

@@ -26,6 +26,7 @@ _cfg_target_lufs = -14
 _cfg_target_tp = -1.0
 _cfg_target_lra = 11
 _cfg_audio_stream = None  # None = prompt, int = index, "skip" = no audio extraction
+_cfg_stems = [None, None]  # stem_a, stem_b from config
 try:
     try:
         import tomllib  # py3.11+
@@ -71,6 +72,10 @@ try:
                 _cfg_audio_stream = "skip"
             elif isinstance(val, (int, float)):
                 _cfg_audio_stream = int(val)
+        if _ex.get("stem_a"):
+            _cfg_stems[0] = str(_ex["stem_a"])
+        if _ex.get("stem_b"):
+            _cfg_stems[1] = str(_ex["stem_b"])
         if _cfg_inputs:
             print(f"[config] loaded {CONFIG_PATH}: duration={_cfg_duration}s start={_cfg_start}s target_fps={_cfg_target_fps}")
 except Exception as _e:
@@ -381,10 +386,11 @@ if len(valid_fps) >= 2:
 # ─── Prepare output folder ───
 os.makedirs(OUT_DIR, exist_ok=True)
 
-for INPUT_FILE in INPUT_FILES:
+for _file_idx, INPUT_FILE in enumerate(INPUT_FILES):
 
     # ─── Derive output filenames ───
-    stem = os.path.splitext(os.path.basename(INPUT_FILE))[0]
+    cfg_stem = _cfg_stems[_file_idx] if _file_idx < len(_cfg_stems) else None
+    stem = cfg_stem if cfg_stem else os.path.splitext(os.path.basename(INPUT_FILE))[0]
     video_out = os.path.join(OUT_DIR, f"{stem}_video.mkv")  # FFV1
     audio_out = os.path.join(OUT_DIR, f"{stem}_audio.wav")  # PCM f32