youtube-dl extremely high fragmentation (dashsegments) and very slow downloading of each segment

[kpopempire]

Checklist

• I'm reporting a broken site support issue
• [x ] I've verified that I'm running youtube-dl version 2021.02.10
• 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 bug reports including closed ones
• I've read bugs section in FAQ

Verbose log

DO NOT MARK THIS BUG AS DUPLICATE WITHOUT SHOWING WHAT IT IS DUPLICATE OF!!!!!
THERE IS NO DUPLICATE OF THIS BUG! (NONE THAT I COULD FIND ANYWAY)

$ youtube-dl -vv -k -i -f bestvideo+bestaudio --external-downloader aria2c --external-downloader-args "-s 16 -j 16 -x 16 -k 20M" uWPIsaYpY7U
[debug] System config: []
[debug] User config: []
[debug] Custom config: []
[debug] Command-line args: ['-vv', '-k', '-i', '-f', 'bestvideo+bestaudio', '--external-downloader', 'aria2c', '--external-downloader-args', '-s 16 -j 16 -x 16 -k 20M', 'uWPIsaYpY7U']
[debug] Encodings: locale UTF-8, fs utf-8, out utf-8, pref UTF-8
[debug] youtube-dl version 2021.02.10
[debug] Python version 3.8.6 (CPython) - Linux-5.11.0-051100rc7-lowlatency-x86_64-with-glibc2.32
[debug] exe versions: ffmpeg 4.3.1, ffprobe 4.3.1
[debug] Proxy map: {}
[youtube] uWPIsaYpY7U: Downloading webpage
[youtube] uWPIsaYpY7U: Downloading MPD manifest
WARNING: Requested formats are incompatible for merge and will be merged into mkv.
[debug] Invoking downloader on 'https://manifest.googlevideo.com/api/manifest/dash/expire/1613528382/ei/3igsYKqSDMLE4wHtzouYAg/ip/98.7.219.241/id/b963c8b1a62963b5/source/youtube/requiressl/yes/playback_host/r1---sn-ab5szn7l.googlevideo.com/mh/a4/mm/31%2C29/mn/sn-ab5szn7l%2Csn-ab5l6nzy/ms/au%2Crdu/mv/m/mvi/1/pl/18/hfr/all/as/fmp4_audio_clear%2Cwebm_audio_clear%2Cwebm2_audio_clear%2Cfmp4_sd_hd_clear%2Cwebm2_sd_hd_clear/initcwndbps/1926250/vprv/1/mt/1613506126/fvip/1/keepalive/yes/itag/0/sparams/expire%2Cei%2Cip%2Cid%2Csource%2Crequiressl%2Chfr%2Cas%2Cvprv%2Citag/sig/AOq0QJ8wRQIhALxmEAIu24yniLXr84a5V8Rnt6di4U1oZAR0Ib78MO9tAiBam0JFMqlLcA983n6MfT7UbtG9NcnAQ8WqmY9ZfNIF2w%3D%3D/lsparams/playback_host%2Cmh%2Cmm%2Cmn%2Cms%2Cmv%2Cmvi%2Cpl%2Cinitcwndbps/lsig/AG3C_xAwRQIhANgSn3ZRK-F_ERVsMJAG63L7rSlFNqxA_6xjfIvQzx9VAiAN96zsvwo1RmcbqIwHkDLv46pgoAf8TxlvgEBX8xzsXA%3D%3D'
[dashsegments] Total fragments: 5698
[download] Destination: Project Management Full Course _ Learn Project Management In 8 Hours _ Simplilearn-uWPIsaYpY7U.f248.webm
[download] 100% of 793.65MiB in 02:12
[debug] Invoking downloader on 'https://r1---sn-ab5szn7l.googlevideo.com/videoplayback?expire=1613528382&ei=3igsYKqSDMLE4wHtzouYAg&ip=98.7.219.241&id=o-AKMclu6Ksh1RUBzYuu7wn4Oi3uyxluqR1iQ5nAEzbfik&itag=140&source=youtube&requiressl=yes&mh=a4&mm=31%2C29&mn=sn-ab5szn7l%2Csn-ab5l6nzy&ms=au%2Crdu&mv=m&mvi=1&pl=18&initcwndbps=1926250&vprv=1&mime=audio%2Fmp4&ns=epgscbnLVJ1vFthMfN8A64AF&gir=yes&clen=472013354&otfp=1&dur=29165.585&lmt=1613143079250813&mt=1613506126&fvip=1&keepalive=yes&c=WEB&txp=6211222&n=gPyvCCkc8nPpjuHa3d&sparams=expire%2Cei%2Cip%2Cid%2Citag%2Csource%2Crequiressl%2Cvprv%2Cmime%2Cns%2Cgir%2Cclen%2Cotfp%2Cdur%2Clmt&sig=AOq0QJ8wRQIhAIziYUVNVbPYOvlwWnHkwpgBrA1ARBCDJ14j1OEPYXMtAiAIHvrifs5A0PSuEV_OcOyevTQ4Sg6WIX4USSsobqVSbQ%3D%3D&lsparams=mh%2Cmm%2Cmn%2Cms%2Cmv%2Cmvi%2Cpl%2Cinitcwndbps&lsig=AG3C_xAwRQIgeviqoVXAa4EfMMVpDIyURcuLS_fr_cN8BS3UmJJOlQgCIQD5iDU8UAsBB2rGAQrb3KiJUxfj3OjtPjUfiDDIBhiAig%3D%3D'
[download] Destination: Project Management Full Course _ Learn Project Management In 8 Hours _ Simplilearn-uWPIsaYpY7U.f140.m4a
[debug] aria2c command line: aria2c -c -s 16 -j 16 -x 16 -k 20M --out 'Project Management Full Course _ Learn Project Management In 8 Hours _ Simplilearn-uWPIsaYpY7U.f140.m4a.part' --header 'User-Agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/70.0.3538.14 Safari/537.36' --header 'Accept-Charset: ISO-8859-1,utf-8;q=0.7,*;q=0.7' --header 'Accept: text/html,application/xhtml+xml,application/xml;q=0.9,*/*;q=0.8' --header 'Accept-Encoding: gzip, deflate' --header 'Accept-Language: en-us,en;q=0.5' --check-certificate=true --remote-time=true -- 'https://r1---sn-ab5szn7l.googlevideo.com/videoplayback?expire=1613528382&ei=3igsYKqSDMLE4wHtzouYAg&ip=98.7.219.241&id=o-AKMclu6Ksh1RUBzYuu7wn4Oi3uyxluqR1iQ5nAEzbfik&itag=140&source=youtube&requiressl=yes&mh=a4&mm=31%2C29&mn=sn-ab5szn7l%2Csn-ab5l6nzy&ms=au%2Crdu&mv=m&mvi=1&pl=18&initcwndbps=1926250&vprv=1&mime=audio%2Fmp4&ns=epgscbnLVJ1vFthMfN8A64AF&gir=yes&clen=472013354&otfp=1&dur=29165.585&lmt=1613143079250813&mt=1613506126&fvip=1&keepalive=yes&c=WEB&txp=6211222&n=gPyvCCkc8nPpjuHa3d&sparams=expire%2Cei%2Cip%2Cid%2Citag%2Csource%2Crequiressl%2Cvprv%2Cmime%2Cns%2Cgir%2Cclen%2Cotfp%2Cdur%2Clmt&sig=AOq0QJ8wRQIhAIziYUVNVbPYOvlwWnHkwpgBrA1ARBCDJ14j1OEPYXMtAiAIHvrifs5A0PSuEV_OcOyevTQ4Sg6WIX4USSsobqVSbQ%3D%3D&lsparams=mh%2Cmm%2Cmn%2Cms%2Cmv%2Cmvi%2Cpl%2Cinitcwndbps&lsig=AG3C_xAwRQIgeviqoVXAa4EfMMVpDIyURcuLS_fr_cN8BS3UmJJOlQgCIQD5iDU8UAsBB2rGAQrb3KiJUxfj3OjtPjUfiDDIBhiAig%3D%3D'

02/16 15:21:57 [NOTICE] Downloading 1 item(s)

02/16 15:21:57 [NOTICE] Allocating disk space. Use --file-allocation=none to disable it. See --file-allocation option in man page for more details.

Description

DO NOT MARK THIS BUG AS DUPLICATE WITHOUT SHOWING WHAT IT IS DUPLICATE OF!!!!!
THERE IS NO DUPLICATE OF THIS BUG! (NONE THAT I COULD FIND ANYWAY)
Very slow download with extremely high fragmentation (dashsegments). I have a very fast internet connection but downloading a relatively small file (500Mb) from youtube takes more than 15 to 20 minutes on some videos. I can download other videos that are much larger 2 to 3Gb in far less time. The speed varies but the fastest I can download these strange video files is about 1 to 3 Mbps and the speed never stays constant. It is always fluctuating between 1 and 3 Mbps. These files are normal youtube.com video files from respected channels.

The above log shows a download time of 2 minutes, but that is incorrect because I had to restart the download several times. The last time I restarted the download it finished the rest of the download (the last 4%) in about 2 minutes. The whole download took over 20 minutes. I started the download then checked for the file 15 minutes later and it was still downloading. Most of the files I download on youtube are about 2 Gb or higher and they usually download in about 2 to 3 minutes. This file is less than a Gb and it taking about 15 to 20 minutes to download.
Over 5000 segments??!! I can download a 4K kpop video (about 4 Gb) in less than 5 minutes, but this 500 Mb video file is taking over 15 minutes to download. wtf???

[dstftw]

#14523