Some mpd manifests give float() argument must be a string or a number, not 'NoneType'

Checklist

• I’m reporting a bug unrelated to a specific site
• I’ve verified that I’m running yt-dlp version 2022.02.04. (update instructions)
• 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. DO NOT post duplicates
• I’ve read the guidelines for opening an issue

Description

I was trying to check the available video formats from a dash manifest but I got this error.

Verbose log

yt-dlp -vU -F --allow-un "https://dtvott-abc.akamaized.net/dash_live_1125/manifest.mpd"
[debug] Command-line config: ['-vU', '-F', '--allow-un', 'https://dtvott-abc.akamaized.net/dash_live_1125/manifest.mpd']
WARNING: You have asked for UNPLAYABLE formats to be listed/downloaded. This is a developer option intended for debugging.
         If you experience any issues while using this option, DO NOT open a bug report
[debug] Encodings: locale cp1252, fs utf-8, out utf-8 (No ANSI), err utf-8 (No ANSI), pref cp1252
[debug] yt-dlp version 2022.02.04 [c1653e9] (win_exe)
[debug] Python version 3.8.10 (CPython 64bit) - Windows-8.1-6.3.9600-SP0
[debug] exe versions: ffmpeg 2021-06-23-git-947122f111-full_build-www.gyan.dev (setts), ffprobe 2021-06-23-git-947122f111-full_build-www.gyan.dev
[debug] Optional libraries: Cryptodome, mutagen, sqlite, websockets
[debug] Proxy map: {}
Latest version: 2022.02.04, Current version: 2022.02.04
yt-dlp is up to date (2022.02.04)
[debug] [generic] Extracting URL: https://dtvott-abc.akamaized.net/dash_live_1125/manifest.mpd
[generic] manifest: Requesting header
WARNING: [generic] Falling back on generic information extractor.
[generic] manifest: Downloading webpage
[generic] manifest: Extracting information
ERROR: float() argument must be a string or a number, not 'NoneType'
Traceback (most recent call last):
  File "yt_dlp\YoutubeDL.py", line 1381, in wrapper
  File "yt_dlp\YoutubeDL.py", line 1451, in __extract_info
  File "yt_dlp\extractor\common.py", line 612, in extract
  File "yt_dlp\extractor\generic.py", line 2824, in _real_extract
  File "yt_dlp\extractor\common.py", line 2878, in _parse_mpd_formats_and_subtitles
TypeError: float() argument must be a string or a number, not 'NoneType'

[pukkandan]

WARNING: You have asked for UNPLAYABLE formats to be listed/downloaded. This is a developer option intended for debugging.
         If you experience any issues while using this option, DO NOT open a bug report

Normally I would simply close this issue. But in this specific case, there is a storyboards format in the manifest that can be extracted without the use of --allow-unplayable-formats

[dirkf]

This patch, using the above tactic, fixes the problem URL, though possibly not all cases where the duration is not known from the AdaptationSet itself:

--- old/yt-dlp/yt_dlp/extractor/common.py
+++ new/yt-dlp/yt_dlp/extractor/common.py
@@ -75,6 +75,7 @@
     str_to_int,
     strip_or_none,
     traverse_obj,
+    try_get,
     unescapeHTML,
     UnsupportedError,
     unified_strdate,
@@ -2966,6 +2967,10 @@
                                 f['url'] = initialization_url
                             f['fragments'].append({location_key(initialization_url): initialization_url})
                         f['fragments'].extend(representation_ms_info['fragments'])
+                        if period_duration is None:
+                            period_duration = try_get(
+                                representation_ms_info,
+                                lambda r: sum(frag['duration'] for frag in r['fragments']), float)
                     else:
                         # Assuming direct URL to unfragmented media.
                         f['url'] = base_url

The video formats only appear with --allow-unplayable-formats.