Download the best quality audio file with youtube-dl [closed]

I have just download youtube-dl so I can download video and audio files from youtube.

I want to download the best audio from the following video: https://www.youtube.com/watch?v=uWusmdmc0to

When I do a search for all formats with youtube-dl I get the following results:

format code  extension  resolution note
249          webm       audio only DASH audio   58k , opus @ 50k, 18.99MiB
250          webm       audio only DASH audio   75k , opus @ 70k, 25.20MiB
140          m4a        audio only DASH audio  131k , m4a_dash container, mp4a.40.2@128k, 52.40MiB
251          webm       audio only DASH audio  147k , opus @160k, 50.95MiB
171          webm       audio only DASH audio  149k , vorbis@128k, 52.64MiB
278          webm       256x144    144p  109k , webm container, vp9, 25fps, video only, 34.62MiB
160          mp4        256x144    144p  117k , avc1.4d400c, 25fps, video only, 37.86MiB
242          webm       426x240    240p  245k , vp9, 25fps, video only, 75.13MiB
133          mp4        426x240    240p  258k , avc1.4d4015, 25fps, video only, 81.39MiB
243          webm       640x360    360p  492k , vp9, 25fps, video only, 142.99MiB
134          mp4        640x360    360p  673k , avc1.4d401e, 25fps, video only, 215.29MiB
244          webm       854x480    480p  828k , vp9, 25fps, video only, 256.58MiB
135          mp4        854x480    480p 1516k , avc1.4d401e, 25fps, video only, 408.56MiB
247          webm       1280x720   720p 1882k , vp9, 25fps, video only, 526.18MiB
136          mp4        1280x720   720p 3012k , avc1.4d401f, 25fps, video only, 803.36MiB
248          webm       1920x1080  1080p 3622k , vp9, 25fps, video only, 938.81MiB
137          mp4        1920x1080  1080p 4724k , avc1.640028, 25fps, video only, 1.44GiB
271          webm       2560x1440  1440p 9253k , vp9, 25fps, video only, 2.86GiB
313          webm       3840x2160  2160p 18685k , vp9, 25fps, video only, 6.33GiB
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)

What is the best choice to get the best audio file? The first five are audio only. Do I need to pick one here? Or is the last one MP4 HD720 the best option and then convert it to MP3?

Thanks!

If you want mp3, just tell youtube-dl that:

youtube-dl -x --audio-format mp3 https://www.youtube.com/watch?v=uWusmdmc0to

will get you an audio version (-x, short for --extract-audio) in or converted to mp3 (that's the --audio-format option). youtube-dl will automatically pick the best quality and most appropriate format.

Note that the listed qualities are just guesses. In practice, opus is superior to anything else, but vorbis is picked for compatibility (refer to this related answer of mine for more details), so that will be picked.

While you can use -f to select a particular format, this is intended for people who want lower quality because of limited bandwidth or storage space, or for debugging. By default, youtube-dl already downloads the highest quality.

To perform this command you need ffmpeg installed (audio and video converter which youtube-dl uses for convertion)

To download audio from a single movie:

youtube-dl -f "bestaudio/best" -ciw -o "%(title)s.%(ext)s" -v --extract-audio --audio-quality 0 --audio-format mp3  https://www.youtube.com/watch?v=c29tZVZpZGVvUGxheWxpc3RQYXJ0

It downloads only audio (without video) and converts it to mp3.

Option --audio-quality 0 is very important there!
Without this option you lose some sound quality during mp3 compression.

--audio-quality 0 tells youtube-dl to save audio file in the best quality (when converting to mp3).
Without this option mp3 audio-quality is set by default to 5 in 0-9 scale where 0 is the best quality and 9 the worst quality. So by default quality is worse. Youtube streams for nonpremium users with variable bitrate up to 160kbps in opus format. Opus format is newer than mp3 and has better compression than mp3 preserving the same quality. So 160kbps opus = ~256kbps mp3.
When audio-quality is default (5 in 0-9 scale) mp3 bitrate is limited to 160kbps which means that some sound quality is lost during compression. When audio-quality is set to 0 mp3 goes up to 300kbps preserving original quality.

To download audio from all movies from a channel

Command is the same, but you should put link to the channel instead of link to a single video:

youtube-dl -f "bestaudio/best" -ciw -o "%(title)s.%(ext)s" -v --extract-audio --audio-quality 0 --audio-format mp3 https://www.youtube.com/c/someChannelName1232143/videos

To download audio from a playlist

You have to add --yes-playlist option.
You can put a link to a playlist (link with playlist word):

youtube-dl -f "bestaudio/best" -ciw -o "%(title)s.%(ext)s" -v --extract-audio --audio-format mp3 --audio-quality 0  --yes-playlist https://www.youtube.com/playlist?list=c29tZVZpZGVvVVJMUGFy

Or the link to one of the songs from playlist while playing playlist (link with list word):

youtube-dl -f "bestaudio/best" -ciw -o "%(title)s.%(ext)s" -v --extract-audio --audio-format mp3 --audio-quality 0  --yes-playlist "https://www.youtube.com/watch?v=c29tZVZpZGVvUGxheWxpc3RQYXJ0&list=c29tZVZpZGVvTGlzdFBhcnRzc29tZVZpZGVvTGlzdFBhcnRz&index=4"

Command options explanation:

-f "bestaudio/best" <- Choose the best audio format.
As there is only audio format listed only the audio is downloaded.

-c <- (--continue) Force resume of partially downloaded files.
By default, youtube-dl will resume downloads if possible.
As docs state maybe it is default, but I put it to make sure it is set.

-i <- (--ignore-errors) Continue on download errors,
for example to skip unavailable videos in a playlist.

-w <- (--no-overtwrites) Do not overwrite files
(If something was already downloaded
and is present in the directory then continue with the next video)

-o "%(title)s.%(ext)s" <- (--output) Output filename template,
in this case it gives you file named movieTitle.mp3
where movieTitle is the title of the video on youtube.

-v <- (--verbose) Print various debugging information

--extract-audio <- (-x) Convert video files to audio-only files
(requires ffmpeg or avconv and ffprobe or avprobe)

--audio-quality 0 <- Specify ffmpeg/avconv audio quality,
insert a value between 0 (better) and 9 (worse) for VBR or a specific
bitrate like 128K (default 5).
Youtube streams for nonpremium users with variable bitrate up to 160kbps in opus format.
Opus format is newer than mp3 and has better compression than mp3
preserving the same quality. So 160kbps opus = ~ 256kbps mp3.  
When audio-quality is default (5 in 0-9 scale) mp3 bitrate
is limited to 160kbps which means that some sound quality is lost during compression.
When audio-quality is set to 0 mp3 goes up to 300kbps preserving original quality.

--audio-format mp3 <-  Specify audio format: "best", "aac", "flac", "mp3", "m4a",
"opus", "vorbis", or "wav"; "best" by default; No effect without -x (--extract-audio).
In this case we choose mp3.
Alternatively you could choose for example opus which
is oryginally provided by youtube and is newer and better than mp3
or flac which is loseless codec.

All links that I provided there are fake. I just put some random words encoded by base64 in them. So you have to replace them by your own links to make it work.

Hint:

Youtube-dl gives you opportunity to use your own youtube account to download stuff.
If your account is a premium account you can get
higher 320kbps opus bitrate which is equivalent of ~512kbps mp3.
Using your own account might be possible by setting --username and --pasword
(See Authentication Options in --help)

Download best audio:

youtube-dl -f bestaudio https://www.youtube.com/watch?v=3_y2jVPmPBw --output "out.%(ext)s"

This should give you the best sound quality:

youtube-dl --extract-audio "https://www.youtube.com/watch?v=uWusmdmc0to"

I'd recommend not to specify any audio format. If you specify an audio format then that probably is different from the original encoding and you will lose sound quality.

I use a bat file in windows, which passes the youtube url through to a preset list of arguments to download the highest quality audio stream and save it as MP3.

batch file contains:

youtube-dl -f bestaudio -x --audio-format mp3 %*

save the batch file in the same dir as youtube-dl (I save it as youtube-mp3.bat) in the same directory have ffmpeg installed

Whenever I want to download audio (Usually for me a youtube DJ Mix) I just pass the (youtube) URL to the batch file. Saves having to remember what arguments to use each time.

youtube-mp3 https://www.youtube.com/?v=xxxxxx