# 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
+ # Also leave '-' intact in order not to break streaming to stdout.
+ return 'file:' + fn if fn != '-' else fn
class FFmpegExtractAudioPP(FFmpegPostProcessor):