max-filesize or similar doesn't work for twitter or facebook with python

[mateusfmcota]

Checklist

• [ x] I'm asking a question
• [ x] I've looked through the README and FAQ for similar questions
• [ x] I've searched the bugtracker for similar questions including closed ones

Question

I'm trying to limit the filesize download throught a python script but it doesn't work on sites like twitter or facebook but works on youtube

ydl_opts = {
            'download_archive': './video',
            'restrictfilenames': True,
            'format': 'best[filesize<50M]',
            'outtmpl': os.getcwd()+'/a/%(title)s-%(id)s.%(ext)s',
            'prefer_ffmpeg': True,
            'postprocessor_args': ['-preset', 'ultrafast'],
            'postprocessors': [{
                'key': 'FFmpegVideoConvertor',
                'preferedformat': 'mp4'
            }],
            'verbose': True
            # 'extension' : 'mp4'
        }

Here's a few combinations of formats I tried also but they didn't worked:

            'format': [{
                'max_filesize': '50MiB'
            }],

            'format': '[filesize<=50M]',

            'format': [{'max-filesize' : '50MiB'}],

Here's the output when I download something from twitter:

[debug] Encodings: locale UTF-8, fs utf-8, out utf-8, pref UTF-8
[debug] youtube-dl version 2020.09.20
[debug] Python version 3.8.6 (CPython) - Linux-5.8.13-arch1-1-x86_64-with-glibc2.2.5
[debug] exe versions: ffmpeg 4.3.1, ffprobe 4.3.1, rtmpdump 2.4
[debug] Proxy map: {}
[twitter] 1314998435385421824: Downloading guest token
[twitter] 1314998435385421824: Downloading JSON metadata
[twitter] 1314998435385421824: Downloading m3u8 information
ERROR: requested format not available
Traceback (most recent call last):
  File "/usr/lib/python3.8/site-packages/youtube_dl/YoutubeDL.py", line 808, in extract_info
    return self.process_ie_result(ie_result, download, extra_info)
  File "/usr/lib/python3.8/site-packages/youtube_dl/YoutubeDL.py", line 863, in process_ie_result
    return self.process_video_result(ie_result, download=download)
  File "/usr/lib/python3.8/site-packages/youtube_dl/YoutubeDL.py", line 1635, in process_video_result
    raise ExtractorError('requested format not available',
youtube_dl.utils.ExtractorError: requested format not available

Traceback (most recent call last):
  File "/usr/lib/python3.8/site-packages/youtube_dl/YoutubeDL.py", line 808, in extract_info
    return self.process_ie_result(ie_result, download, extra_info)
  File "/usr/lib/python3.8/site-packages/youtube_dl/YoutubeDL.py", line 863, in process_ie_result
    return self.process_video_result(ie_result, download=download)
  File "/usr/lib/python3.8/site-packages/youtube_dl/YoutubeDL.py", line 1635, in process_video_result
    raise ExtractorError('requested format not available',
youtube_dl.utils.ExtractorError: requested format not available

During handling of the above exception, another exception occurred:

Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
  File "<stdin>", line 3, in down
  File "/usr/lib/python3.8/site-packages/youtube_dl/YoutubeDL.py", line 820, in extract_info
    self.report_error(compat_str(e), e.format_traceback())
  File "/usr/lib/python3.8/site-packages/youtube_dl/YoutubeDL.py", line 625, in report_error
    self.trouble(error_message, tb)
  File "/usr/lib/python3.8/site-packages/youtube_dl/YoutubeDL.py", line 595, in trouble
    raise DownloadError(message, exc_info)
youtube_dl.utils.DownloadError: ERROR: requested format not available

How can I control the max file size to be downloaded and to make it work on every site.

[dstftw]

You can't. Not all site provides filesize metadata.