Make ffmpeg directory path absolute (#1184)

Author: fenom

src/torchcodec/_core/ops.py

@@ -101,7 +101,7 @@ def load_torchcodec_shared_libraries() -> tuple[int, str]:
     if ffmpeg_path := shutil.which("ffmpeg"):
 
         def expose_ffmpeg_dlls():  # noqa: F811
-            ffmpeg_dir = Path(ffmpeg_path).parent
+            ffmpeg_dir = Path(ffmpeg_path).parent.absolute()
             return os.add_dll_directory(str(ffmpeg_dir))  # that's the actual CM