Download audio only with youtube-dl

Download audio only with youtube-dl

youtube-dl -F https://www.youtube.com/watch?v=m6p9L3LK_9g

[youtube] m6p9L3LK_9g: Downloading video info webpage
[youtube] m6p9L3LK_9g: Extracting video information
WARNING: unable to extract uploader nickname
[youtube] m6p9L3LK_9g: Downloading MPD manifest
[info] Available formats for m6p9L3LK_9g:
format code  extension  resolution note
139          m4a        audio only DASH audio   49k , m4a_dash container, mp4a.40.5@ 48k (22050Hz), 1.78MiB
249          webm       audio only DASH audio   51k , opus @ 50k, 1.79MiB
250          webm       audio only DASH audio   76k , opus @ 70k, 2.54MiB
171          webm       audio only DASH audio   94k , vorbis@128k, 3.34MiB
140          m4a        audio only DASH audio  128k , m4a_dash container, mp4a.40.2@128k (44100Hz), 4.74MiB
251          webm       audio only DASH audio  141k , opus @160k, 4.88MiB
160          mp4        256x144    DASH video  111k , avc1.42c00c, 15fps, video only, 4.07MiB
278          webm       256x144    144p  114k , webm container, vp9, 15fps, video only, 3.51MiB
242          webm       426x240    240p  237k , vp9, 30fps, video only, 5.58MiB
133          mp4        426x240    DASH video  254k , avc1.4d4015, 30fps, video only, 9.13MiB
243          webm       640x360    360p  432k , vp9, 30fps, video only, 9.80MiB
134          mp4        640x360    DASH video  606k , avc1.4d401e, 30fps, video only, 14.00MiB
244          webm       854x480    480p  782k , vp9, 30fps, video only, 16.50MiB
135          mp4        854x480    DASH video 1110k , avc1.4d401f, 30fps, video only, 28.23MiB
247          webm       1280x720   720p 1448k , vp9, 30fps, video only, 30.60MiB
136          mp4        1280x720   DASH video 2215k , avc1.4d401f, 30fps, video only, 53.96MiB
17           3gp        176x144    small , mp4v.20.3, mp4a.40.2@ 24k
36           3gp        320x180    small , mp4v.20.3, mp4a.40.2
43           webm       640x360    medium , vp8.0, vorbis@128k
18           mp4        640x360    medium , avc1.42001E, mp4a.40.2@ 96k
22           mp4        1280x720   hd720 , avc1.64001F, mp4a.40.2@192k (best)




youtube-dl -f 251 https://www.youtube.com/watch?v=m6p9L3LK_9g