diff --git a/pyproject.toml b/pyproject.toml
index b611c10..d03cbb6 100644
--- a/pyproject.toml
+++ b/pyproject.toml
@@ -4,7 +4,7 @@ build-backend = "setuptools.build_meta"
 
 [project]
 name = "tiddl"
-version = "3.4.3"
+version = "3.4.4a1"
 description = "Download Tidal tracks with CLI downloader."
 readme = "README.md"
 requires-python = ">=3.13"
diff --git a/tiddl/cli/app.py b/tiddl/cli/app.py
index 20dde22..337505d 100644
--- a/tiddl/cli/app.py
+++ b/tiddl/cli/app.py
@@ -13,7 +13,7 @@ log = logging.getLogger("tiddl")
 app = typer.Typer(name="tiddl", no_args_is_help=True, rich_markup_mode="rich")
 register_commands(app)
 
-VERSION = "v3.4.3"
+VERSION = "v3.4.4a1"
 
 
 @app.callback()
diff --git a/tiddl/core/utils/parse.py b/tiddl/core/utils/parse.py
index 5575b9a..811dde1 100644
--- a/tiddl/core/utils/parse.py
+++ b/tiddl/core/utils/parse.py
@@ -6,6 +6,8 @@ from xml.etree.ElementTree import fromstring
 
 from tiddl.core.api.models import TrackStream, VideoStream
 
+DOLBY_CODECS = ["eac3", "ac4"]
+
 
 def parse_manifest_XML(xml_content: str):
     """
@@ -80,7 +82,7 @@ def parse_track_stream(track_stream: TrackStream) -> tuple[list[str], str]:
         file_extension = ".flac"
         if track_stream.audioQuality == "HI_RES_LOSSLESS":
             file_extension = ".m4a"
-    elif codecs.startswith("mp4") or codecs == "eac3":
+    elif codecs.startswith("mp4") or codecs in DOLBY_CODECS:
         file_extension = ".m4a"
     else:
         raise ValueError(f"Unknown codecs `{codecs}` (trackId {track_stream.trackId}")