KeyError: 'url' when trying to download from youtube with [ext=mp4]

[jmburges]

Checklist

• I'm reporting a broken site support
• I've verified that I'm running youtube-dl version 2021.01.08
• I've checked that all provided URLs are alive and playable in a browser
• I've checked that all URLs and arguments with special characters are properly quoted or escaped
• I've searched the bugtracker for similar issues including closed ones

Verbose log

youtube-dl --download-archive archive.txt --max-downloads 20 -f 'bestvideo[height<=1080]+bestvideo[ext=mp4]+bestaudio' -v --mark-watched https://www.youtube.com/watch\?v\=SqeFX9Xv6Jo

[debug] System config: []
[debug] User config: []
[debug] Custom config: []
[debug] Command-line args: ['--download-archive', 'archive.txt', '--max-downloads', '20', '-f', 'bestvideo[height<=1080]+bestvideo[ext=mp4]+bestaudio', '-v', '--mark-watched', 'https://www.youtube.com/watch?v=SqeFX9Xv6Jo']
[debug] Encodings: locale UTF-8, fs utf-8, out utf-8, pref UTF-8
[debug] youtube-dl version 2021.01.08
[debug] Python version 3.8.5 (CPython) - Linux-3.16.85-62-aarch64-with-glibc2.29
[debug] exe versions: ffmpeg 4.2.4, ffprobe 4.2.4
[debug] Proxy map: {}
[youtube] SqeFX9Xv6Jo: Downloading webpage
[debug] Invoking downloader on 'https://r2---sn-8xgp1vo-xfgl.googlevideo.com/videoplayback?expire=1610573074&ei=shD_X9mbHofghgapmbnoCg&ip=108.6.22.232&id=o-AEdvkOx-GAcNpRjANv46Nu6Fmnsu7s8NjMMk1TgxdWSv&itag=137&aitags=133%2C134%2C135%2C136%2C137%2C160%2C242%2C243%2C244%2C247%2C248%2C271%2C278%2C313%2C394%2C395%2C396%2C397%2C398%2C399%2C400%2C401&source=youtube&requiressl=yes&mh=o_&mm=31%2C29&mn=sn-8xgp1vo-xfgl%2Csn-ab5l6n6e&ms=au%2Crdu&mv=m&mvi=2&pl=16&initcwndbps=1528750&vprv=1&mime=video%2Fmp4&ns=Hh1pQHq7ci8btaWHnRhs6DAF&gir=yes&clen=82034251&dur=462.958&lmt=1601909345763417&mt=1610551234&fvip=2&keepalive=yes&c=WEB&txp=5532432&n=a9QzkyeXl0jEMf&sparams=expire%2Cei%2Cip%2Cid%2Caitags%2Csource%2Crequiressl%2Cvprv%2Cmime%2Cns%2Cgir%2Cclen%2Cdur%2Clmt&sig=AOq0QJ8wRQIhAKcz1uiVAIRc2PeIUIx2E-BOUE5YeCShkcqwReTFAUjHAiBr1EwfOj8MlWR1wHWb4IHrSm3o2i2j9YZBC6ZDHWiwOg%3D%3D&lsparams=mh%2Cmm%2Cmn%2Cms%2Cmv%2Cmvi%2Cpl%2Cinitcwndbps&lsig=AG3C_xAwRgIhAJFTGeKAgxsZwrbohlDrvDNaXZzWvHh2X29L2aYsPBzbAiEAueFvhX2QS59jE-MBDV1w04y_kP_0QaE4_7nQSRdSfos%3D&ratebypass=yes'
[download] How Pimp My Ride actually started Car Trek-SqeFX9Xv6Jo.f137.mp4 has already been downloaded
[download] 100% of 78.23MiB
Traceback (most recent call last):
  File "/usr/local/bin/youtube-dl", line 8, in <module>
    sys.exit(main())
  File "/usr/local/lib/python3.8/dist-packages/youtube_dl/__init__.py", line 474, in main
    _real_main(argv)
  File "/usr/local/lib/python3.8/dist-packages/youtube_dl/__init__.py", line 464, in _real_main
    retcode = ydl.download(all_urls)
  File "/usr/local/lib/python3.8/dist-packages/youtube_dl/YoutubeDL.py", line 2028, in download
    res = self.extract_info(
  File "/usr/local/lib/python3.8/dist-packages/youtube_dl/YoutubeDL.py", line 796, in extract_info
    return self.__extract_info(url, ie, download, extra_info, process)
  File "/usr/local/lib/python3.8/dist-packages/youtube_dl/YoutubeDL.py", line 803, in wrapper
    return func(self, *args, **kwargs)
  File "/usr/local/lib/python3.8/dist-packages/youtube_dl/YoutubeDL.py", line 835, in __extract_info
    return self.process_ie_result(ie_result, download, extra_info)
  File "/usr/local/lib/python3.8/dist-packages/youtube_dl/YoutubeDL.py", line 869, in process_ie_result
    return self.process_video_result(ie_result, download=download)
  File "/usr/local/lib/python3.8/dist-packages/youtube_dl/YoutubeDL.py", line 1654, in process_video_result
    self.process_info(new_info)
  File "/usr/local/lib/python3.8/dist-packages/youtube_dl/YoutubeDL.py", line 1930, in process_info
    partial_success = dl(fname, new_info)
  File "/usr/local/lib/python3.8/dist-packages/youtube_dl/YoutubeDL.py", line 1870, in dl
    fd = get_suitable_downloader(info, self.params)(self, self.params)
  File "/usr/local/lib/python3.8/dist-packages/youtube_dl/downloader/__init__.py", line 34, in get_suitable_downloader
    protocol = determine_protocol(info_dict)
  File "/usr/local/lib/python3.8/dist-packages/youtube_dl/utils.py", line 4290, in determine_protocol
    url = info_dict['url']
KeyError: 'url'

Description

Trying to download the mp4 version of a youtube playlist. When I do it with the mp4 flag, it gives me this error. If I remove the [ext=mp4] everything works!

[dstftw]

Invalid format selection expression: there must be only one + operator.