youtube-dl --verbose --merge-output-format mp4 -f "bestvideo[ext=mp4]+bestaudio[ext=m4a]"  https://www.youtube.com/watch?v=AeUPQa5H8BI
[debug] System config: []
[debug] User config: []
[debug] Custom config: []
[debug] Command-line args: ['--verbose', '--merge-output-format', 'mp4', '-f', 'bestvideo[ext=mp4]+bestaudio[ext=m4a]', 'https://www.youtube.com/watch?v=AeUPQa5H8BI']
[debug] Encodings: locale cp1252, fs mbcs, out cp437, pref cp1252
[debug] youtube-dl version 2020.03.08
[debug] Python version 3.4.4 (CPython) - Windows-10-10.0.18362
[debug] exe versions: ffmpeg 3.2.1, ffprobe 4.2.2
[debug] Proxy map: {}
[youtube] AeUPQa5H8BI: Downloading webpage
[debug] Invoking downloader on 'https://r1---sn-n4v7knlz.googlevideo.com/videoplayback?expire=1585277146&ei=ehR9Xs6KCZq9kwbr2ImwBQ&ip=98.176.94.192&id=o-AJnesCCEEPCG1GGNmtO4j95qUos1xJPdT2o-s1_TGF3i&itag=137&aitags=133%2C134%2C135%2C136%2C137%2C160%2C242%2C243%2C244%2C247%2C248%2C278&source=youtube&requiressl=yes&mh=wn&mm=31%2C26&mn=sn-n4v7knlz%2Csn-a5mekn7k&ms=au%2Conr&mv=m&mvi=0&pl=16&initcwndbps=1687500&vprv=1&mime=video%2Fmp4&gir=yes&clen=97184468&dur=322.355&lmt=1454048319655424&mt=1585255420&fvip=1&keepalive=yes&c=WEB&sparams=expire%2Cei%2Cip%2Cid%2Caitags%2Csource%2Crequiressl%2Cvprv%2Cmime%2Cgir%2Cclen%2Cdur%2Clmt&sig=ADKhkGMwRQIgelYB8jk9F0gfsgQE32bBK3kNlViApkmNaYZ5ExLDFekCIQDRz2KOoBLcOrOrbJ0lBWsWYMaiG4cV26fLlt77GaGOVg%3D%3D&lsparams=mh%2Cmm%2Cmn%2Cms%2Cmv%2Cmvi%2Cpl%2Cinitcwndbps&lsig=ABSNjpQwRQIhAKf2MTgZZZfvfQ9MNxH_OUTd7l7MH7EM0OTo3EHs0KBnAiA1HZ5qdIrl-V1vkiT9EeDAOh7nyo1aI7twhliscEWfog%3D%3D&ratebypass=yes'
[download] Destination: Neil Tyson & Steven Tyler Talking Science Backstage at The Late Show with Stephen Colbert-AeUPQa5H8BI.f137.mp4
[download] 100% of 92.68MiB in 00:06
[debug] Invoking downloader on 'https://r1---sn-n4v7knlz.googlevideo.com/videoplayback?expire=1585277146&ei=ehR9Xs6KCZq9kwbr2ImwBQ&ip=98.176.94.192&id=o-AJnesCCEEPCG1GGNmtO4j95qUos1xJPdT2o-s1_TGF3i&itag=140&source=youtube&requiressl=yes&mh=wn&mm=31%2C26&mn=sn-n4v7knlz%2Csn-a5mekn7k&ms=au%2Conr&mv=m&mvi=0&pl=16&initcwndbps=1687500&vprv=1&mime=audio%2Fmp4&gir=yes&clen=5121687&dur=322.409&lmt=1454047166929240&mt=1585255420&fvip=1&keepalive=yes&c=WEB&sparams=expire%2Cei%2Cip%2Cid%2Citag%2Csource%2Crequiressl%2Cvprv%2Cmime%2Cgir%2Cclen%2Cdur%2Clmt&sig=ADKhkGMwRgIhAKDlo_2nbj_c1DOWzj4iq_hgJy1i4NOVWO-PKkC9gnHXAiEA9SsOAJ62a5OIu-6lI6Bueudf2PT-5mo97hJ8xkRqdt4%3D&lsparams=mh%2Cmm%2Cmn%2Cms%2Cmv%2Cmvi%2Cpl%2Cinitcwndbps&lsig=ABSNjpQwRQIhAKf2MTgZZZfvfQ9MNxH_OUTd7l7MH7EM0OTo3EHs0KBnAiA1HZ5qdIrl-V1vkiT9EeDAOh7nyo1aI7twhliscEWfog%3D%3D&ratebypass=yes'
[download] Destination: Neil Tyson & Steven Tyler Talking Science Backstage at The Late Show with Stephen Colbert-AeUPQa5H8BI.f140.m4a
[download] 100% of 4.88MiB in 00:00
[ffmpeg] Merging formats into "Neil Tyson & Steven Tyler Talking Science Backstage at The Late Show with Stephen Colbert-AeUPQa5H8BI.mp4"
[debug] ffmpeg command line: ffmpeg -y -loglevel "repeat+info" -i "file:Neil Tyson & Steven Tyler Talking Science Backstage at The Late Show with Stephen Colbert-AeUPQa5H8BI.f137.mp4" -i "file:Neil Tyson & Steven Tyler Talking Science Backstage at The Late Show with Stephen Colbert-AeUPQa5H8BI.f140.m4a" -c copy -map "0:v:0" -map "1:a:0" "file:Neil Tyson & Steven Tyler Talking Science Backstage at The Late Show with Stephen Colbert-AeUPQa5H8BI.temp.mp4"
Deleting original file Neil Tyson & Steven Tyler Talking Science Backstage at The Late Show with Stephen Colbert-AeUPQa5H8BI.f137.mp4 (pass -k to keep)
Deleting original file Neil Tyson & Steven Tyler Talking Science Backstage at The Late Show with Stephen Colbert-AeUPQa5H8BI.f140.m4a (pass -k to keep)