fix: use stream selectors instead of map list in mux_video_audio

app.py

@@ -327,11 +327,12 @@ def mux_video_audio(silent_video: str, audio_path: str, output_path: str,
         from hunyuanvideo_foley.utils.media_utils import merge_audio_video
         merge_audio_video(audio_path, silent_video, output_path)
     else:
+        v_in = ffmpeg.input(silent_video)
+        a_in = ffmpeg.input(audio_path)
         ffmpeg.output(
-            ffmpeg.input(silent_video),
-            ffmpeg.input(audio_path),
+            v_in["v:0"],
+            a_in["a:0"],
             output_path,
-            map=["0:v:0", "1:a:0"],
             vcodec="libx264", preset="fast", crf=18,
             pix_fmt="yuv420p",
             acodec="aac", audio_bitrate="128k",