diff --git a/twitchdl/ffmpeg.py b/twitchdl/ffmpeg.py
new file mode 100644
index 0000000..f7ab409
--- /dev/null
+++ b/twitchdl/ffmpeg.py
@@ -0,0 +1,76 @@
+import asyncio
+import json
+import logging
+import re
+
+from asyncio.subprocess import PIPE
+from pprint import pprint
+from typing import Optional
+
+from twitchdl.output import print_out
+
+
+async def join_vods(playlist_path: str, target: str, overwrite: bool, video: dict):
+    command = [
+        "ffmpeg",
+        "-i", playlist_path,
+        "-c", "copy",
+        "-metadata", "artist={}".format(video["creator"]["displayName"]),
+        "-metadata", "title={}".format(video["title"]),
+        "-metadata", "encoded_by=twitch-dl",
+        "-stats",
+        "-loglevel", "warning",
+        f"file:{target}",
+    ]
+
+    if overwrite:
+        command.append("-y")
+
+    # command = ["ls", "-al"]
+
+    print_out("<dim>{}</dim>".format(" ".join(command)))
+    process = await asyncio.create_subprocess_exec(*command, stdout=PIPE, stderr=PIPE)
+
+    assert process.stderr is not None
+
+    await asyncio.gather(
+        # _read_stream("stdout", process.stdout),
+        _print_progress("stderr", process.stderr),
+        process.wait()
+    )
+
+    print(process.returncode)
+
+
+async def _read_stream(name: str, stream: Optional[asyncio.StreamReader]):
+    if stream:
+        async for line in readlines(stream):
+            print(name, ">", line)
+
+
+async def _print_progress(stream: asyncio.StreamReader):
+    async for line in readlines(stream):
+        print(name, ">", line)
+
+
+pattern = re.compile(br"[\r\n]+")
+
+
+async def readlines(stream: asyncio.StreamReader):
+    data = bytearray()
+
+    while not stream.at_eof():
+        lines = pattern.split(data)
+        data[:] = lines.pop(-1)
+
+        for line in lines:
+            yield line
+
+        data.extend(await stream.read(1024))
+
+
+if __name__ == "__main__":
+    # logging.basicConfig(level=logging.DEBUG)
+    video = json.loads('{"id": "1555108011", "title": "Cult of the Lamb", "publishedAt": "2022-08-07T17:00:30Z", "broadcastType": "ARCHIVE", "lengthSeconds": 17948, "game": {"name": "Cult of the Lamb"}, "creator": {"login": "bananasaurus_rex", "displayName": "Bananasaurus_Rex"}, "playlists": [{"bandwidth": 8446533, "resolution": [1920, 1080], "codecs": "avc1.64002A,mp4a.40.2", "video": "chunked", "uri": "https://d1m7jfoe9zdc1j.cloudfront.net/278bcbd011d28f96b856_bananasaurus_rex_40035345017_1659891626/chunked/index-dvr.m3u8"}, {"bandwidth": 3432426, "resolution": [1280, 720], "codecs": "avc1.4D0020,mp4a.40.2", "video": "720p60", "uri": "https://d1m7jfoe9zdc1j.cloudfront.net/278bcbd011d28f96b856_bananasaurus_rex_40035345017_1659891626/720p60/index-dvr.m3u8"}, {"bandwidth": 1445268, "resolution": [852, 480], "codecs": "avc1.4D001F,mp4a.40.2", "video": "480p30", "uri": "https://d1m7jfoe9zdc1j.cloudfront.net/278bcbd011d28f96b856_bananasaurus_rex_40035345017_1659891626/480p30/index-dvr.m3u8"}, {"bandwidth": 215355, "resolution": null, "codecs": "mp4a.40.2", "video": "audio_only", "uri": "https://d1m7jfoe9zdc1j.cloudfront.net/278bcbd011d28f96b856_bananasaurus_rex_40035345017_1659891626/audio_only/index-dvr.m3u8"}, {"bandwidth": 705523, "resolution": [640, 360], "codecs": "avc1.4D001E,mp4a.40.2", "video": "360p30", "uri": "https://d1m7jfoe9zdc1j.cloudfront.net/278bcbd011d28f96b856_bananasaurus_rex_40035345017_1659891626/360p30/index-dvr.m3u8"}, {"bandwidth": 285614, "resolution": [284, 160], "codecs": "avc1.4D000C,mp4a.40.2", "video": "160p30", "uri": "https://d1m7jfoe9zdc1j.cloudfront.net/278bcbd011d28f96b856_bananasaurus_rex_40035345017_1659891626/160p30/index-dvr.m3u8"}]}')
+    playlist_path = "/tmp/twitch-dl/278bcbd011d28f96b856_bananasaurus_rex_40035345017_1659891626/160p30/playlist_downloaded.m3u8"
+    asyncio.run(join_vods(playlist_path, "out.mkv", True, video), debug=True)