fluminus_cli chokes on empty multimedia

[zhongfu]

I have a multimedia file in Luminus which appears to have content (the progress bar says that it's >1h long), but the m3u8 playlist from citcastmedia.nus.edu.sg is actually empty:

#EXTM3U
#EXT-X-VERSION:3
#EXT-X-TARGETDURATION:10
#EXT-X-MEDIA-SEQUENCE:0
#EXT-X-ENDLIST

As a result, ffmpeg fails when it tries to transcode the stream, which causes fluminus_cli to retry silently, forever.

[indocomsoft]

As a hack, one can create an empty file where this multimedia file would have been written. Right now, fluminus_cli only checks for file existence.

Probably I could add a check for "does not contain any stream" in the ffmpeg output, but this sounds brittle :/

[indocomsoft]

Alternatively, one can also go to lib/fluminus_cli/constants.ex and change def gen_retry_options, do: [retries: :infinity, delay: 0, exp_base: 1] to, for example, retry n times only