Repository: yt-dlp
Issue: ERROR: [Errno 2] No such file or directory: 'Schwärze [-b2w6fKq-ls].f247.webm' after successful DL 
Labels: bug,cant-reproduce,core:post-processor

### Checklist

- [X] I'm reporting a bug unrelated to a specific site
- [X] I've verified that I'm running yt-dlp version **2022.04.08** ([update instructions](https://github.com/yt-dlp/yt-dlp#update)) or later (specify commit)
- [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](https://github.com/ytdl-org/youtube-dl#video-url-contains-an-ampersand-and-im-getting-some-strange-output-1-2839-or-v-is-not-recognized-as-an-internal-or-external-command)
- [X] I've searched the [bugtracker](https://github.com/yt-dlp/yt-dlp/issues?q=) for similar issues including closed ones. DO NOT post duplicates
- [X] I've read the [guidelines for opening an issue](https://github.com/yt-dlp/yt-dlp/blob/master/CONTRIBUTING.md#opening-an-issue)

### Description

I try to download audiobooks from youtube which mostly works fine. Some dont work. For example

    https://www.youtube.com/watch?v=-b2w6fKq-ls

Its most probably related to german umlauts ( "ä" ), but it seems thats not always a problem. Also I sometimes have the "same" file in the directory two times (it must be a encoding issue, but iam not sure how to debug that proper).

I fiddled around alot. Tried passing LC_ALL with different values. Same with youtube-dl btw.



### Verbose log

```shell
Θ yt-dlp -v https://www.youtube.com/watch\?v\=-b2w6fKq-ls
[debug] Command-line config: ['-v', 'https://www.youtube.com/watch?v=-b2w6fKq-ls']
[debug] Encodings: locale UTF-8, fs utf-8, out utf-8, err utf-8, pref UTF-8
[debug] yt-dlp version 2022.04.08 [7884ade65]
[debug] Python version 3.9.12 (CPython 64bit) - Linux-5.10.52-gentoo-nyx-x86_64-Intel-R-_Core-TM-_i5-3570_CPU_@_3.40GHz-with-glibc2.34
[debug] Checking exe version: ffmpeg -bsfs
[debug] Checking exe version: ffprobe -bsfs
[debug] exe versions: ffmpeg 4.4.1 (setts), ffprobe 4.4.1
[debug] Optional libraries: certifi, Crypto, sqlite
[debug] Proxy map: {}
[debug] [youtube] Extracting URL: https://www.youtube.com/watch?v=-b2w6fKq-ls
[youtube] -b2w6fKq-ls: Downloading webpage
[youtube] -b2w6fKq-ls: Downloading android player API JSON
[debug] Sort order given by extractor: quality, res, fps, hdr:12, source, codec:vp9.2, lang, proto
[debug] Formats sorted by: hasvid, ie_pref, quality, res, fps, hdr:12(7), source, vcodec:vp9.2(10), acodec, lang, proto, filesize, fs_approx, tbr, vbr, abr, asr, vext, aext, hasaud, id
[debug] Default format spec: bestvideo*+bestaudio/best
[info] -b2w6fKq-ls: Downloading 1 format(s): 247+251
[debug] Invoking downloader on "https://rr4---sn-4g5lzned.googlevideo.com/videoplayback?expire=1652486713&ei=2Z1-YvnQMuKI6dsPuPeDoAI&ip=95.89.149.19&id=o-AI3XBwKw4tIxapH9N_e2XPFeemzQBP8O1Ql-wvA4Ybvh&itag=247&source=youtube&requiressl=yes&mh=dj&mm=31%2C26&mn=sn-4g5lzned%2Csn-f5f7lnee&ms=au%2Conr&mv=m&mvi=4&pl=24&initcwndbps=1593750&vprv=1&mime=video%2Fwebm&gir=yes&clen=840256021&dur=34822.495&lmt=1646006663446241&mt=1652464866&fvip=2&keepalive=yes&fexp=24001373%2C24007246&c=ANDROID&txp=5437434&sparams=expire%2Cei%2Cip%2Cid%2Citag%2Csource%2Crequiressl%2Cvprv%2Cmime%2Cgir%2Cclen%2Cdur%2Clmt&sig=AOq0QJ8wRAIgMbfkIKOB0kC0u6W0pfxcr3LeOTl1UVPukUpkdVTOhggCIC7AurQ-_rc5Cvq_4ST8XRdRid_oBFZSVFeqWmf-SuHJ&lsparams=mh%2Cmm%2Cmn%2Cms%2Cmv%2Cmvi%2Cpl%2Cinitcwndbps&lsig=AG3C_xAwRQIhAIaZV4iwRBDJnt1gbSDAWqmaEhd9aXnnT8hZBPx1yP0cAiBOSZCsRnqMioUN1V8YJ8Bk15fGThZ0UqiAHAZKCBeH5g%3D%3D"
[download] Destination: Schwärze [-b2w6fKq-ls].f247.webm
[download] 100% of 801.33MiB in 01:55
[debug] Invoking downloader on "https://rr4---sn-4g5lzned.googlevideo.com/videoplayback?expire=1652486713&ei=2Z1-YvnQMuKI6dsPuPeDoAI&ip=95.89.149.19&id=o-AI3XBwKw4tIxapH9N_e2XPFeemzQBP8O1Ql-wvA4Ybvh&itag=251&source=youtube&requiressl=yes&mh=dj&mm=31%2C26&mn=sn-4g5lzned%2Csn-f5f7lnee&ms=au%2Conr&mv=m&mvi=4&pl=24&initcwndbps=1593750&vprv=1&mime=audio%2Fwebm&gir=yes&clen=451879189&dur=34822.521&lmt=1646010978429248&mt=1652464866&fvip=2&keepalive=yes&fexp=24001373%2C24007246&c=ANDROID&txp=5432434&sparams=expire%2Cei%2Cip%2Cid%2Citag%2Csource%2Crequiressl%2Cvprv%2Cmime%2Cgir%2Cclen%2Cdur%2Clmt&sig=AOq0QJ8wRQIhANMRuLRi0fvXgyGa2Dz3Le_5557WMdAa3dkgc5j9-n_MAiB2c2_-_pbRRqJ3dESRHD4s-wY_iZuaUs6Tfiu1qgvR3A%3D%3D&lsparams=mh%2Cmm%2Cmn%2Cms%2Cmv%2Cmvi%2Cpl%2Cinitcwndbps&lsig=AG3C_xAwRQIhAIaZV4iwRBDJnt1gbSDAWqmaEhd9aXnnT8hZBPx1yP0cAiBOSZCsRnqMioUN1V8YJ8Bk15fGThZ0UqiAHAZKCBeH5g%3D%3D"
[download] Destination: Schwärze [-b2w6fKq-ls].f251.webm
[download] 100% of 430.95MiB in 01:03
[Merger] Merging formats into "Schwärze [-b2w6fKq-ls].webm"
ERROR: [Errno 2] No such file or directory: 'Schwärze [-b2w6fKq-ls].f247.webm'
Traceback (most recent call last):
  File "/usr/lib/python3.9/site-packages/yt_dlp/YoutubeDL.py", line 1408, in wrapper
    return func(self, *args, **kwargs)
  File "/usr/lib/python3.9/site-packages/yt_dlp/YoutubeDL.py", line 1492, in __extract_info
    return self.process_ie_result(ie_result, download, extra_info)
  File "/usr/lib/python3.9/site-packages/yt_dlp/YoutubeDL.py", line 1548, in process_ie_result
    ie_result = self.process_video_result(ie_result, download=download)
  File "/usr/lib/python3.9/site-packages/yt_dlp/YoutubeDL.py", line 2648, in process_video_result
    self.process_info(new_info)
  File "/usr/lib/python3.9/site-packages/yt_dlp/YoutubeDL.py", line 3211, in process_info
    replace_info_dict(self.post_process(dl_filename, info_dict, files_to_move))
  File "/usr/lib/python3.9/site-packages/yt_dlp/YoutubeDL.py", line 3379, in post_process
    info = self.run_all_pps('post_process', info, additional_pps=info.get('__postprocessors'))
  File "/usr/lib/python3.9/site-packages/yt_dlp/YoutubeDL.py", line 3366, in run_all_pps
    info = self.run_pp(pp, info)
  File "/usr/lib/python3.9/site-packages/yt_dlp/YoutubeDL.py", line 3339, in run_pp
    files_to_delete, infodict = pp.run(infodict)
  File "/usr/lib/python3.9/site-packages/yt_dlp/postprocessor/common.py", line 27, in run
    ret = func(self, info, *args, **kwargs)
  File "/usr/lib/python3.9/site-packages/yt_dlp/postprocessor/common.py", line 124, in wrapper
    return func(self, info)
  File "/usr/lib/python3.9/site-packages/yt_dlp/postprocessor/ffmpeg.py", line 828, in run
    self.run_ffmpeg_multiple_files(info['__files_to_merge'], temp_filename, args)
  File "/usr/lib/python3.9/site-packages/yt_dlp/postprocessor/ffmpeg.py", line 288, in run_ffmpeg_multiple_files
    return self.real_run_ffmpeg(
  File "/usr/lib/python3.9/site-packages/yt_dlp/postprocessor/ffmpeg.py", line 295, in real_run_ffmpeg
    oldest_mtime = min(
  File "/usr/lib/python3.9/site-packages/yt_dlp/postprocessor/ffmpeg.py", line 296, in <genexpr>
    os.stat(encodeFilename(path)).st_mtime for path, _ in input_path_opts if path)
FileNotFoundError: [Errno 2] No such file or directory: 'Schwärze [-b2w6fKq-ls].f247.webm'

 Θ file Schwärze\ \[-b2w6fKq-ls\].f247.webm
Schwärze [-b2w6fKq-ls].f247.webm: WebM
```