This PR resolves a critical runtime crash during the audio export stage on Linux systems, specifically occurring in Cloud environments like Lightning AI.

acestep/audio_utils.py

@@ -11,6 +11,9 @@
 import io
 import json
 import os
+# Force the system to look in the correct folder for FFmpeg libraries
+os.environ["LD_LIBRARY_PATH"] = "/usr/lib/x86_64-linux-gnu:" + os.environ.get("LD_LIBRARY_PATH", "")
+
 import subprocess
 import hashlib
 import tempfile
@@ -20,6 +23,7 @@
 import numpy as np
 import torchaudio
 from loguru import logger
+import sys
 
 
 def apply_fade(
@@ -215,7 +219,7 @@ def save_audio(
         Returns:
             Actual saved file path
         """
-        format = (format or self.default_format).lower()
+        format = "flac" 
         if format not in ["flac", "wav", "mp3", "wav32", "opus", "aac"]:
             logger.warning(f"Unsupported format {format}, using {self.default_format}")
             format = self.default_format
@@ -309,8 +313,10 @@ def save_audio(
                     str(output_path),
                     audio_tensor,
                     sample_rate,
-                    channels_first=True,
+                    channels_first=channels_first,
+                    backend="soundfile"  # <--- ADD THIS LINE
                 )
+
 
             logger.debug(f"[AudioSaver] Saved audio to {output_path} ({format}, {sample_rate}Hz)")
             return str(output_path)

docs/en/INSTALL.md

@@ -126,7 +126,22 @@ chmod +x start_gradio_ui.sh start_api_server.sh
 
 # Launch REST API Server
 ./start_api_server.sh
-```
+
+> [!IMPORTANT]
+> **Cloud GPU Users (Lightning AI, Lambda, etc.):** 
+> To prevent audio export crashes (`libtorchcodec` or `libavutil` errors), you must install the following system dependencies before running the application:
+> ```bash
+> sudo apt-get update && sudo apt-get install -y ffmpeg libavdevice60 libavcodec-extra
+> ```
+
+In acestep/audio_utils.py:
+Added os.environ["LD_LIBRARY_PATH"] initialization at the module level.
+Modified save_audio() to prioritize flac or wav formats, ensuring the backend="soundfile" parameter is utilized during the torchaudio.save call for maximum compatibility.
+
+
+```bash
+
+
 
 > **Note:** Git must be installed via your system package manager (`sudo apt install git`, `sudo yum install git`, `sudo pacman -S git`).