diff --git a/youtube_dl/downloader/external.py b/youtube_dl/downloader/external.py
index cda39fe978..8d642fc3e6 100644
--- a/youtube_dl/downloader/external.py
+++ b/youtube_dl/downloader/external.py
@@ -235,10 +235,7 @@ def _call_downloader(self, tmpfilename, info_dict):
             args += ['-f', EXT_TO_OUT_FORMATS.get(info_dict['ext'], info_dict['ext'])]
 
         args = [encodeArgument(opt) for opt in args]
-        if tmpfilename == '-':
-            args.append('pipe:1')
-        else:
-            args.append(encodeFilename(ffpp._ffmpeg_filename_argument(tmpfilename), True))
+        args.append(encodeFilename(ffpp._ffmpeg_filename_argument(tmpfilename), True))
 
         self._debug_cmd(args)
 
diff --git a/youtube_dl/postprocessor/ffmpeg.py b/youtube_dl/postprocessor/ffmpeg.py
index b64cd396bc..30af6eb5a5 100644
--- a/youtube_dl/postprocessor/ffmpeg.py
+++ b/youtube_dl/postprocessor/ffmpeg.py
@@ -175,7 +175,7 @@ def _ffmpeg_filename_argument(self, fn):
         # Always use 'file:' because the filename may contain ':' (ffmpeg
         # interprets that as a protocol) or can start with '-' (-- is broken in
         # ffmpeg, see https://ffmpeg.org/trac/ffmpeg/ticket/2127 for details)
-        return 'file:' + fn
+        return 'file:' + fn if fn != '-' else fn
 
 
 class FFmpegExtractAudioPP(FFmpegPostProcessor):