If you want to download mp3 list from youtube, you can use the excellent utility youtube-dl. At the command prompt type:
youtube-dl --extract-audio --audio-format mp3 -i <id list>
If you want download single mp4 file, type:
youtube-dl -f mp4 <video link>To select the video quality, first use the -F option to list the available formats, here’s an example:
[$ youtube-dl -F https://youtu.be/KkaOa_Y9VmQ
[youtube] KkaOa_Y9VmQ: Downloading webpage
[info] Available formats for KkaOa_Y9VmQ:
format code extension resolution note
249 webm audio only tiny 44k , webm_dash container, opus @ 44k (48000Hz), 25.00MiB
250 webm audio only tiny 56k , webm_dash container, opus @ 56k (48000Hz), 31.84MiB
251 webm audio only tiny 111k , webm_dash container, opus @111k (48000Hz), 62.17MiB
140 m4a audio only tiny 129k , m4a_dash container, mp4a.40.2@129k (44100Hz), 72.42MiB
160 mp4 256x144 144p 62k , mp4_dash container, avc1.4d400c@ 62k, 25fps, video only, 35.14MiB
278 webm 256x144 144p 80k , webm_dash container, vp9@ 80k, 25fps, video only, 45.18MiB
394 mp4 256x144 144p 82k , mp4_dash container, av01.0.00M.08@ 82k, 25fps, video only, 46.27MiB
133 mp4 426x240 240p 147k , mp4_dash container, avc1.4d4015@ 147k, 25fps, video only, 82.65MiB
242 webm 426x240 240p 157k , webm_dash container, vp9@ 157k, 25fps, video only, 88.28MiB
395 mp4 426x240 240p 166k , mp4_dash container, av01.0.00M.08@ 166k, 25fps, video only, 93.29MiB
134 mp4 640x360 360p 307k , mp4_dash container, avc1.4d401e@ 307k, 25fps, video only, 172.19MiB
396 mp4 640x360 360p 311k , mp4_dash container, av01.0.01M.08@ 311k, 25fps, video only, 174.48MiB
243 webm 640x360 360p 341k , webm_dash container, vp9@ 341k, 25fps, video only, 190.77MiB
135 mp4 854x480 480p 506k , mp4_dash container, avc1.4d401e@ 506k, 25fps, video only, 283.15MiB
397 mp4 854x480 480p 557k , mp4_dash container, av01.0.04M.08@ 557k, 25fps, video only, 311.67MiB
244 webm 854x480 480p 615k , webm_dash container, vp9@ 615k, 25fps, video only, 344.13MiB
136 mp4 1280x720 720p 835k , mp4_dash container, avc1.4d401f@ 835k, 25fps, video only, 467.46MiB
398 mp4 1280x720 720p 961k , mp4_dash container, av01.0.05M.08@ 961k, 25fps, video only, 537.92MiB
247 webm 1280x720 720p 1206k , webm_dash container, vp9@1206k, 25fps, video only, 674.99MiB
399 mp4 1920x1080 1080p 1620k , mp4_dash container, av01.0.08M.08@1620k, 25fps, video only, 906.43MiB
248 webm 1920x1080 1080p 2166k , webm_dash container, vp9@2166k, 25fps, video only, 1.18GiB
137 mp4 1920x1080 1080p 2632k , mp4_dash container, avc1.640028@2632k, 25fps, video only, 1.44GiB
400 mp4 2560x1440 1440p 4346k , mp4_dash container, av01.0.12M.08@4346k, 25fps, video only, 2.37GiB
271 webm 2560x1440 1440p 6210k , webm_dash container, vp9@6210k, 25fps, video only, 3.39GiB
401 mp4 3840x2160 2160p 8488k , mp4_dash container, av01.0.12M.08@8488k, 25fps, video only, 4.64GiB
313 webm 3840x2160 2160p 14344k , webm_dash container, vp9@14344k, 25fps, video only, 7.84GiB
18 mp4 640x360 360p 639k , avc1.42001E, 25fps, mp4a.40.2 (44100Hz), 357.64MiB
22 mp4 1280x720 720p 964k , avc1.64001F, 25fps, mp4a.40.2 (44100Hz) (best)
The best quality is 22 so use -f 22 instead of -F to download the MP4 video with 1280×720 resolution like this:
youtube-dl -f 22 <video link>