Retrieve YouTube content and metadata

kafy, API, YouTube, download, video
pip install kafy==1.1


🍀 Kafy

https://travis-ci.org/SenuGamerBoy/Kafay.svg?branch=develop https://coveralls.io/repos/github/SenuGamerBoy/Kafay/badge.svg?branch=develop Wheel Status


  • Retreive metadata such as viewcount, duration, rating, author, thumbnail, keywords
  • Download video or audio at requested resolution / bitrate / format / filesize
  • Command line tool (ytdl) for downloading directly from the command line
  • Retrieve the URL to stream the video in a player such as vlc or mplayer
  • Works with age-restricted videos and non-embeddable videos
  • Small, standalone, single importable module file (kafy.py)
  • Select highest quality stream for download or streaming
  • Download video only (no audio) in m4v or webm format
  • Download audio only (no video) in ogg or m4a format
  • Retreive playlists and playlist metadata
  • Works with Python 2.6+ and 3.3+
  • Optionally depends on youtube-dl (recommended; more stable)

Usage Examples

Here is how to use the module in your own python code. For command line tool (ytdl) instructions, see further below

>>> import kafy

create a video instance from a YouTube url:

>>> url = "https://www.youtube.com/watch?v=9AUu6Ddq78Y"
>>> video = kafy.new(url)

get certain attributes:

>>> video.title
'Python for Beginners - Learn Python in 1 Hour'

>>> video.rating

>>> video.viewcount, video.author, video.length
(2557209, 'Programming with Mosh', 10394)

>>> video.duration, video.likes, video.dislikes
('02:53:14', 25, 0)

>>> print(video.description)
Speaker: Python for Beginners

list available streams for a video:

>>> streams = video.streams
>>> for s in streams:
...     print(s)

show all formats, file-sizes and their download url:

>>> for s in streams:
...    print(s.resolution, s.extension, s.get_filesize(), s.url)
1280x720 mp4 2421958510 https://r1---sn-aiglln7e.googlevideo.com/videoplayba[...]
640x360 webm 547015732 https://r1---sn-aiglln7e.googlevideo.com/videoplaybac[...]
640x360 mp4 470655850 https://r1---sn-aiglln7e.googlevideo.com/videoplayback[...]
320x240 flv 345455674 https://r1---sn-aiglln7e.googlevideo.com/videoplayback[...]
320x240 3gp 208603447 https://r1---sn-aiglln7e.googlevideo.com/videoplayback[...]
176x144 3gp 60905732 https://r1---sn-aiglln7e.googlevideo.com/videoplayback?[...]

get best resolution regardless of file format:

>>> best = video.getbest()
>>> best.resolution, best.extension
('1280x720', 'mp4')

get best resolution for a particular file format: (mp4, webm, flv or 3gp)

>>> best = video.getbest(preftype="webm")
>>> best.resolution, best.extension
('640x360', 'webm')

get url, for download or streaming in mplayer / vlc etc:

>>> best.url

Download video and show progress:

>>> best.download(quiet=False)
3,734,976 Bytes [0.20%] received. Rate: [ 719 KB/s].  ETA: [3284 secs]

Download video, use specific directory and/or filename:

>>> filename = best.download(filepath="/tmp/")

>>> filename = best.download(filepath="/tmp/Game." + best.extension)

Get audio-only streams (m4a and/or ogg vorbis):

>>> audiostreams = video.audiostreams
>>> for a in audiostreams:
...     print(a.bitrate, a.extension, a.get_filesize())
256k m4a 331379079
192k ogg 172524223
128k m4a 166863001
128k ogg 108981120
48k m4a 62700449

Download the 2nd audio stream from the above list:

>>> audiostreams[1].download()

Get the best quality audio stream:

>>> bestaudio = video.getbestaudio()
>>> bestaudio.bitrate

Download the best quality audio file:

>>> bestaudio.download()

show all media types for a video (video+audio, video-only and audio-only):

>>> allstreams = video.allstreams
>>> for s in allstreams:
...     print(s.mediatype, s.extension, s.quality)

normal mp4 1280x720
normal webm 640x360
normal mp4 640x360
normal flv 320x240
normal 3gp 320x240
normal 3gp 176x144
video m4v 1280x720
video webm 1280x720
video m4v 854x480
video webm 854x480
video m4v 640x360
video webm 640x360
video m4v 426x240
video webm 426x240
video m4v 256x144
video webm 256x144
audio m4a 256k
audio ogg 192k
audio m4a 128k
audio ogg 128k
audio m4a 48k


kafy can be installed using pip:

$ [sudo] pip install kafy

or use a virtualenv if you don't want to install it system-wide:

$ virtualenv venv
$ source venv/bin/activate
$ pip install kafy

Command Line Tool (ytdl) Usage

usage: ytdl [-h] [-i] [-s]
            [-t {audio,video,normal,all} [{audio,video,normal,all} ...]]
            [-n N] [-b] [-a]

YouTube Download Tool

positional arguments:
  url                   YouTube video URL to download

optional arguments:
  -h, --help            show this help message and exit
  -i                    Display vid info
  -s                    Display available streams
  -t {audio,video,normal,all} [{audio,video,normal,all} ...]
                        Stream types to display
  -n N                  Specify stream to download by stream number (use -s to
                        list available streams)
  -b                    Download the best quality video (ignores -n)
  -a                    Download the best quality audio (ignores -n)

ytdl Examples

Download best available resolution (-b):

$ ytdl -b "https://www.youtube.com/watch?v=9AUu6Ddq78Y"

Download best available audio stream (-a) (note; the full url is not required, just the video id will suffice):

$ ytdl -a cyMHZVT91Dw

get video info (-i):

$ ytdl -i cyMHZVT91Dw

list available dowload streams:

$ ytdl cyMHZVT91Dw

Stream Type    Format Quality         Size
------ ----    ------ -------         ----
1      normal  webm   [640x360]       33 MB
2      normal  mp4    [640x360]       23 MB
3      normal  flv    [320x240]       14 MB
4      normal  3gp    [320x240]        9 MB
5      normal  3gp    [176x144]        3 MB
6      audio   m4a    [48k]            2 MB
7      audio   m4a    [128k]           5 MB
8      audio   ogg    [128k]           5 MB
9      audio   ogg    [192k]           7 MB
10     audio   m4a    [256k]          10 MB

Download mp4 640x360 (ie. stream number 2):

$ ytdl -n2 cyMHZVT91Dw

Download m4a audio stream at 256k bitrate:

$ ytdl -n10 cyMHZVT91Dw