Can't specify filesize for ffmpeg --external-downloader-args

[D3MZ]

Checklist

• [ ] I'm reporting a broken site support issue
• [x] I've verified that I'm running youtube-dl version 2020.03.01
• [x] I've checked that all provided URLs are alive and playable in a browser
• [x] I've checked that all URLs and arguments with special characters are properly quoted or escaped
• [x] I've searched the bugtracker for similar bug reports including closed ones
• [x] I've read bugs section in FAQ

Verbose log

$ youtube-dl --external-downloader "ffmpeg" --external-downloader-args "-fs 1000M" https://www.aljazeera.com/live/
[generic] live: Requesting header
WARNING: Falling back on generic information extractor.
[generic] live: Downloading webpage
[generic] live: Extracting information
[download] Downloading playlist: LIVE
[generic] playlist LIVE: Collected 1 video ids (downloading 1 of them)
[download] Downloading video 1 of 1
[brightcove:new] 5467349513001: Downloading JSON metadata
[brightcove:new] 5467349513001: Downloading m3u8 information
[download] Destination: AJE - Live stream HD 2020-03-01 15_57-5467349513001.mp4
ffmpeg version 4.2.2 Copyright (c) 2000-2019 the FFmpeg developers
  built with Apple clang version 11.0.0 (clang-1100.0.33.17)
  configuration: --prefix=/usr/local/Cellar/ffmpeg/4.2.2_2 --enable-shared --enable-pthreads --enable-version3 --enable-avresample --cc=clang --host-cflags= --host-ldflags= --enable-ffplay --enable-gnutls --enable-gpl --enable-libaom --enable-libbluray --enable-libmp3lame --enable-libopus --enable-librubberband --enable-libsnappy --enable-libtesseract --enable-libtheora --enable-libvidstab --enable-libvorbis --enable-libvpx --enable-libwebp --enable-libx264 --enable-libx265 --enable-libxvid --enable-lzma --enable-libfontconfig --enable-libfreetype --enable-frei0r --enable-libass --enable-libopencore-amrnb --enable-libopencore-amrwb --enable-libopenjpeg --enable-librtmp --enable-libspeex --enable-libsoxr --enable-videotoolbox --disable-libjack --disable-indev=jack
  libavutil      56. 31.100 / 56. 31.100
  libavcodec     58. 54.100 / 58. 54.100
  libavformat    58. 29.100 / 58. 29.100
  libavdevice    58.  8.100 / 58.  8.100
  libavfilter     7. 57.100 /  7. 57.100
  libavresample   4.  0.  0 /  4.  0.  0
  libswscale      5.  5.100 /  5.  5.100
  libswresample   3.  5.100 /  3.  5.100
  libpostproc    55.  5.100 / 55.  5.100
Option fs (set the limit file size in bytes) cannot be applied to input url https://live-hls-web-aje.getaj.net/AJE/01.m3u8 -- you are trying to apply an input option to an output file or vice versa. Move this option before the file it belongs to.
Error parsing options for input file https://live-hls-web-aje.getaj.net/AJE/01.m3u8.
Error opening input files: Invalid argument

ERROR: ffmpeg exited with code 1

Description

I want to break up 24/7 news livestreams into segments for easier file handling.

[Rosenstein]

There's a pull req #16571 that should fix that issue. It's not merged into master, so you'd have to patch ytdl yourself.