switch to av1 and limit cpu cores

convert/convert.py

@@ -91,8 +91,20 @@ def main():
 
         try:
             cmd = [
+                "taskset", "-c", "0,1,2,3",   # limit to first 4 CPU cores
                 "ffmpeg", "-i", str(src_file),
-                "-vcodec", "libx264", "-acodec", "aac",
+                "-c:v", "libaom-av1",
+                "-c:a", "libopus",
+                "-mapping_family", "1",
+                "-af", "aformat=channel_layouts=5.1",
+                "-c:s", "copy",
+                "-map", "0",
+                "-crf", "24",
+                "-b:v", "0",
+                "-b:a", "128k",
+                "-cpu-used", "4",
+                "-row-mt", "1",
+                "-tiles", "2x2",
                 str(tmp_dst_file)
             ]
             print(f"[CMD] {' '.join(cmd)}")