-r, --limit-rate RATE                Maximum download rate in bytes per
                                     second (e.g. 50K or 4.2M)
-R, --retries RETRIES                Number of retries (default is 10), or
                                     "infinite".
--fragment-retries RETRIES           Number of retries for a fragment
                                     (default is 10), or "infinite" (DASH,
                                     hlsnative and ISM)
--skip-unavailable-fragments         Skip unavailable fragments (DASH,
                                     hlsnative and ISM)
--abort-on-unavailable-fragment      Abort downloading when some fragment is
                                     not available
--keep-fragments                     Keep downloaded fragments on disk after
                                     downloading is finished; fragments are
                                     erased by default
--buffer-size SIZE                   Size of download buffer (e.g. 1024 or
                                     16K) (default is 1024)
--no-resize-buffer                   Do not automatically adjust the buffer
                                     size. By default, the buffer size is
                                     automatically resized from an initial
                                     value of SIZE.
--http-chunk-size SIZE               Size of a chunk for chunk-based HTTP
                                     downloading (e.g. 10485760 or 10M)
                                     (default is disabled). May be useful
                                     for bypassing bandwidth throttling
                                     imposed by a webserver (experimental)
--playlist-reverse                   Download playlist videos in reverse
                                     order
--playlist-random                    Download playlist videos in random
                                     order
--xattr-set-filesize                 Set file xattribute nextdl.filesize with
                                     expected file size
--hls-prefer-native                  Use the native HLS downloader instead
                                     of ffmpeg
--hls-prefer-ffmpeg                  Use ffmpeg instead of the native HLS
                                     downloader
--hls-use-mpegts                     Use the mpegts container for HLS
                                     videos, allowing to play the video
                                     while downloading (some players may not
                                     be able to play it)
--external-downloader COMMAND        Use the specified external downloader.
                                     Currently supports aria2c,avconv,axel,c
                                     url,ffmpeg,httpie,wget
--external-downloader-args ARGS      Give these arguments to the external
                                     downloader

-a, --batch-file FILE                File containing URLs to download ('-'
                                     for stdin), one URL per line. Lines
                                     starting with '#', ';' or ']' are
                                     considered as comments and ignored.
--id                                 Use only video ID in file name
-o, --output TEMPLATE                Output filename template, see the
                                     "OUTPUT TEMPLATE" for all the info
--output-na-placeholder PLACEHOLDER  Placeholder value for unavailable meta
                                     fields in output filename template
                                     (default is "NA")
--autonumber-start NUMBER            Specify the start value for
                                     %(autonumber)s (default is 1)
--restrict-filenames                 Restrict filenames to only ASCII
                                     characters, and avoid "&" and spaces in
                                     filenames
-w, --no-overwrites                  Do not overwrite files
-c, --continue                       Force resume of partially downloaded
                                     files. By default, nextdl will
                                     resume downloads if possible.
--no-continue                        Do not resume partially downloaded
                                     files (restart from beginning)
--no-part                            Do not use .part files - write directly
                                     into output file
--no-mtime                           Do not use the Last-modified header to
                                     set the file modification time
--write-description                  Write video description to a
                                     .description file
--write-info-json                    Write video metadata to a .info.json
                                     file
--write-annotations                  Write video annotations to a
                                     .annotations.xml file
--load-info-json FILE                JSON file containing the video
                                     information (created with the "--write-
                                     info-json" option)
--cookies FILE                       File to read cookies from and dump
                                     cookie jar in
--cache-dir DIR                      Location in the filesystem where
                                     nextdl can store some downloaded
                                     information permanently. By default
                                     $XDG_CACHE_HOME/nextdl or
                                     ~/.cache/nextdl . At the moment,
                                     only YouTube player files (for videos
                                     with obfuscated signatures) are cached,
                                     but that may change.
--no-cache-dir                       Disable filesystem caching
--rm-cache-dir                       Delete all filesystem cache files

--write-thumbnail                    Write thumbnail image to disk
--write-all-thumbnails               Write all thumbnail image formats to
                                     disk
--list-thumbnails                    Simulate and list all available
                                     thumbnail formats

-q, --quiet                          Activate quiet mode
--no-warnings                        Ignore warnings
-s, --simulate                       Do not download the video and do not
                                     write anything to disk
--skip-download                      Do not download the video
-g, --get-url                        Simulate, quiet but print URL
-e, --get-title                      Simulate, quiet but print title
--get-id                             Simulate, quiet but print id
--get-thumbnail                      Simulate, quiet but print thumbnail URL
--get-description                    Simulate, quiet but print video
                                     description
--get-duration                       Simulate, quiet but print video length
--get-filename                       Simulate, quiet but print output
                                     filename
--get-format                         Simulate, quiet but print output format
-j, --dump-json                      Simulate, quiet but print JSON
                                     information. See the "OUTPUT TEMPLATE"
                                     for a description of available keys.
-J, --dump-single-json               Simulate, quiet but print JSON
                                     information for each command-line
                                     argument. If the URL refers to a
                                     playlist, dump the whole playlist
                                     information in a single line.
--print-json                         Be quiet and print the video
                                     information as JSON (video is still
                                     being downloaded).
--newline                            Output progress bar as new lines
--no-progress                        Do not print progress bar
--console-title                      Display progress in console titlebar
-v, --verbose                        Print various debugging information
--dump-pages                         Print downloaded pages encoded using
                                     base64 to debug problems (very verbose)
--write-pages                        Write downloaded intermediary pages to
                                     files in the current directory to debug
                                     problems
--print-traffic                      Display sent and read HTTP traffic
-C, --call-home                      Contact the nextdl server for
                                     debugging
--no-call-home                       Do NOT contact the nextdl server
                                     for debugging

--encoding ENCODING                  Force the specified encoding
                                     (experimental)
--no-check-certificate               Suppress HTTPS certificate validation
--prefer-insecure                    Use an unencrypted connection to
                                     retrieve information about the video.
                                     (Currently supported only for YouTube)
--user-agent UA                      Specify a custom user agent
--referer URL                        Specify a custom referer, use if the
                                     video access is restricted to one
                                     domain
--add-header FIELD:VALUE             Specify a custom HTTP header and its
                                     value, separated by a colon ':'. You
                                     can use this option multiple times
--bidi-workaround                    Work around terminals that lack
                                     bidirectional text support. Requires
                                     bidiv or fribidi executable in PATH
--sleep-interval SECONDS             Number of seconds to sleep before each
                                     download when used alone or a lower
                                     bound of a range for randomized sleep
                                     before each download (minimum possible
                                     number of seconds to sleep) when used
                                     along with --max-sleep-interval.
--max-sleep-interval SECONDS         Upper bound of a range for randomized
                                     sleep before each download (maximum
                                     possible number of seconds to sleep).
                                     Must only be used along with --min-
                                     sleep-interval.

-f, --format FORMAT                  Video format code, see the "FORMAT
                                     SELECTION" for all the info
--all-formats                        Download all available video formats
--prefer-free-formats                Prefer free video formats unless a
                                     specific one is requested
-F, --list-formats                   List all available formats of requested
                                     videos
--youtube-skip-dash-manifest         Do not download the DASH manifests and
                                     related data on YouTube videos
--merge-output-format FORMAT         If a merge is required (e.g.
                                     bestvideo+bestaudio), output to given
                                     container format. One of mkv, mp4, ogg,
                                     webm, flv. Ignored if no merge is
                                     required

--write-sub                          Write subtitle file
--write-auto-sub                     Write automatically generated subtitle
                                     file (YouTube only)
--all-subs                           Download all the available subtitles of
                                     the video
--list-subs                          List all available subtitles for the
                                     video
--sub-format FORMAT                  Subtitle format, accepts formats
                                     preference, for example: "srt" or
                                     "ass/srt/best"
--sub-lang LANGS                     Languages of the subtitles to download
                                     (optional) separated by commas, use
                                     --list-subs for available language tags

-u, --username USERNAME              Login with this account ID
-p, --password PASSWORD              Account password. If this option is
                                     left out, nextdl will ask
                                     interactively.
-2, --twofactor TWOFACTOR            Two-factor authentication code
-n, --netrc                          Use .netrc authentication data
--video-password PASSWORD            Video password (vimeo, youku)

--ap-mso MSO                         Adobe Pass multiple-system operator (TV
                                     provider) identifier, use --ap-list-mso
                                     for a list of available MSOs
--ap-username USERNAME               Multiple-system operator account login
--ap-password PASSWORD               Multiple-system operator account
                                     password. If this option is left out,
                                     nextdl will ask interactively.
--ap-list-mso                        List all supported multiple-system
                                     operators

-x, --extract-audio                  Convert video files to audio-only files
                                     (requires ffmpeg/avconv and
                                     ffprobe/avprobe)
--audio-format FORMAT                Specify audio format: "best", "aac",
                                     "flac", "mp3", "m4a", "opus", "vorbis",
                                     or "wav"; "best" by default; No effect
                                     without -x
--audio-quality QUALITY              Specify ffmpeg/avconv audio quality,
                                     insert a value between 0 (better) and 9
                                     (worse) for VBR or a specific bitrate
                                     like 128K (default 5)
--recode-video FORMAT                Encode the video to another format if
                                     necessary (currently supported:
                                     mp4|flv|ogg|webm|mkv|avi)
--postprocessor-args ARGS            Give these arguments to the
                                     postprocessor
-k, --keep-video                     Keep the video file on disk after the
                                     post-processing; the video is erased by
                                     default
--no-post-overwrites                 Do not overwrite post-processed files;
                                     the post-processed files are
                                     overwritten by default
--embed-subs                         Embed subtitles in the video (only for
                                     mp4, webm and mkv videos)
--embed-thumbnail                    Embed thumbnail in the audio as cover
                                     art
--add-metadata                       Write metadata to the video file
--metadata-from-title FORMAT         Parse additional metadata like song
                                     title / artist from the video title.
                                     The format syntax is the same as
                                     --output. Regular expression with named
                                     capture groups may also be used. The
                                     parsed parameters replace existing
                                     values. Example: --metadata-from-title
                                     "%(artist)s - %(title)s" matches a
                                     title like "Coldplay - Paradise".
                                     Example (regex): --metadata-from-title
                                     "(?P
    
     .+?) - (?P
     
     

  
       CONFIGURATION
 

     
You can configure nextdl by placing any supported command line option to a configuration file. On Linux and macOS, the system wide configuration file is located at /etc/nextdl.conf and the user wide configuration file at ~/.config/nextdl/config. On Windows, the user wide configuration file locations are %APPDATA%\nextdl\config.txt or C:\Users\
       
        \nextdl.conf
       . Note that by default configuration file may not exist so you may need to create it yourself.
 

     
For example, with the following configuration file nextdl will always extract the audio, not copy the mtime, use a proxy and save all videos under Movies directory in your home directory:
 

     

 
      
# Lines starting with # are comments

# Always extract audio
-x

# Do not copy the mtime
--no-mtime

# Use this proxy
--proxy 127.0.0.1:3128

# Save all videos under Movies directory in your home directory
-o ~/Movies/%(title)s.%(ext)s


     
 

     
Note that options in configuration file are just the same options aka switches used in regular command line calls thus there must be no whitespace after - or --, e.g. -o or --proxy but not - o or -- proxy.
 

     
You can use --ignore-config if you want to disable the configuration file for a particular nextdl run.
 

     
You can also use --config-location if you want to use custom configuration file for a particular nextdl run.
 

     

  
       Authentication with .netrc file
 

     
You may also want to configure automatic credentials storage for extractors that support authentication (by providing login and password with --username and --password) in order not to pass credentials as command line arguments on every nextdl execution and prevent tracking plain text passwords in the shell command history. You can achieve this using a .netrc file on a per extractor basis. For that you will need to create a .netrc file in your $HOME and restrict permissions to read/write by only you:
 

     

 
      
touch $HOME/.netrc
chmod a-rwx,u+rw $HOME/.netrc


     
 

     
After that you can add credentials for an extractor in the following format, where extractor is the name of the extractor in lowercase:
 

     

 
      
machine 
        
          login 
         
           password 
          

          
         
        

     
 

     
For example:
 

     

 
      
machine youtube login [email protected] password my_youtube_password
machine twitch login my_twitch_account_name password my_twitch_password


     
 

     
To activate authentication with the .netrc file you should pass --netrc to nextdl or place it in the configuration file.
 

     
On Windows you may also need to setup the %HOME% environment variable manually. For example:
 

     

 
      
set HOME=%USERPROFILE%


     
 

     

  
       OUTPUT TEMPLATE
 

     
The -o option allows users to indicate a template for the output file names.
 

     
tl;dr: navigate me to examples.
 

     
The basic usage is not to set any template arguments when downloading a single file, like in nextdl -o funny_video.flv "https://some/video". However, it may contain special sequences that will be replaced when downloading each video. The special sequences may be formatted according to python string formatting operations. For example, %(NAME)s or %(NAME)05d. To clarify, that is a percent symbol followed by a name in parentheses, followed by formatting operations. Allowed names along with sequence type are:
 

     
 
 
      
id (string): Video identifier
 
 
      
title (string): Video title
 
 
      
url (string): Video URL
 
 
      
ext (string): Video filename extension
 
 
      
alt_title (string): A secondary title of the video
 
 
      
display_id (string): An alternative identifier for the video
 
 
      
uploader (string): Full name of the video uploader
 
 
      
license (string): License name the video is licensed under
 
 
      
creator (string): The creator of the video
 
 
      
release_date (string): The date (YYYYMMDD) when the video was released
 
 
      
timestamp (numeric): UNIX timestamp of the moment the video became available
 
 
      
upload_date (string): Video upload date (YYYYMMDD)
 
 
      
uploader_id (string): Nickname or id of the video uploader
 
 
      
channel (string): Full name of the channel the video is uploaded on
 
 
      
channel_id (string): Id of the channel
 
 
      
location (string): Physical location where the video was filmed
 
 
      
duration (numeric): Length of the video in seconds
 
 
      
view_count (numeric): How many users have watched the video on the platform
 
 
      
like_count (numeric): Number of positive ratings of the video
 
 
      
dislike_count (numeric): Number of negative ratings of the video
 
 
      
repost_count (numeric): Number of reposts of the video
 
 
      
average_rating (numeric): Average rating give by users, the scale used depends on the webpage
 
 
      
comment_count (numeric): Number of comments on the video
 
 
      
age_limit (numeric): Age restriction for the video (years)
 
 
      
is_live (boolean): Whether this video is a live stream or a fixed-length video
 
 
      
start_time (numeric): Time in seconds where the reproduction should start, as specified in the URL
 
 
      
end_time (numeric): Time in seconds where the reproduction should end, as specified in the URL
 
 
      
format (string): A human-readable description of the format
 
 
      
format_id (string): Format code specified by --format
 
 
      
format_note (string): Additional info about the format
 
 
      
width (numeric): Width of the video
 
 
      
height (numeric): Height of the video
 
 
      
resolution (string): Textual description of width and height
 
 
      
tbr (numeric): Average bitrate of audio and video in KBit/s
 
 
      
abr (numeric): Average audio bitrate in KBit/s
 
 
      
acodec (string): Name of the audio codec in use
 
 
      
asr (numeric): Audio sampling rate in Hertz
 
 
      
vbr (numeric): Average video bitrate in KBit/s
 
 
      
fps (numeric): Frame rate
 
 
      
vcodec (string): Name of the video codec in use
 
 
      
container (string): Name of the container format
 
 
      
filesize (numeric): The number of bytes, if known in advance
 
 
      
filesize_approx (numeric): An estimate for the number of bytes
 
 
      
protocol (string): The protocol that will be used for the actual download
 
 
      
extractor (string): Name of the extractor
 
 
      
extractor_key (string): Key name of the extractor
 
 
      
epoch (numeric): Unix epoch when creating the file
 
 
      
autonumber (numeric): Number that will be increased with each download, starting at --autonumber-start
 
 
      
playlist (string): Name or id of the playlist that contains the video
 
 
      
playlist_index (numeric): Index of the video in the playlist padded with leading zeros according to the total length of the playlist
 
 
      
playlist_id (string): Playlist identifier
 
 
      
playlist_title (string): Playlist title
 
 
      
playlist_uploader (string): Full name of the playlist uploader
 
 
      
playlist_uploader_id (string): Nickname or id of the playlist uploader
 

     
 

     
Available for the video that belongs to some logical chapter or section:
 

     
 
 
      
chapter (string): Name or title of the chapter the video belongs to
 
 
      
chapter_number (numeric): Number of the chapter the video belongs to
 
 
      
chapter_id (string): Id of the chapter the video belongs to
 

     
 

     
Available for the video that is an episode of some series or programme:
 

     
 
 
      
series (string): Title of the series or programme the video episode belongs to
 
 
      
season (string): Title of the season the video episode belongs to
 
 
      
season_number (numeric): Number of the season the video episode belongs to
 
 
      
season_id (string): Id of the season the video episode belongs to
 
 
      
episode (string): Title of the video episode
 
 
      
episode_number (numeric): Number of the video episode within a season
 
 
      
episode_id (string): Id of the video episode
 

     
 

     
Available for the media that is a track or a part of a music album:
 

     
 
 
      
track (string): Title of the track
 
 
      
track_number (numeric): Number of the track within an album or a disc
 
 
      
track_id (string): Id of the track
 
 
      
artist (string): Artist(s) of the track
 
 
      
genre (string): Genre(s) of the track
 
 
      
album (string): Title of the album the track belongs to
 
 
      
album_type (string): Type of the album
 
 
      
album_artist (string): List of all artists appeared on the album
 
 
      
disc_number (numeric): Number of the disc or other physical medium the track belongs to
 
 
      
release_year (numeric): Year (YYYY) when the album was released
 

     
 

     
Each aforementioned sequence when referenced in an output template will be replaced by the actual value corresponding to the sequence name. Note that some of the sequences are not guaranteed to be present since they depend on the metadata obtained by a particular extractor. Such sequences will be replaced with placeholder value provided with --output-na-placeholder (NA by default).
 

     
For example for -o %(title)s-%(id)s.%(ext)s and an mp4 video with title nextdl test video and id BaW_jenozKcj, this will result in a nextdl test video-BaW_jenozKcj.mp4 file created in the current directory.
 

     
For numeric sequences you can use numeric related formatting, for example, %(view_count)05d will result in a string with view count padded with zeros up to 5 characters, like in 00042.
 

     
Output templates can also contain arbitrary hierarchical path, e.g. -o '%(playlist)s/%(playlist_index)s - %(title)s.%(ext)s' which will result in downloading each video in a directory corresponding to this path template. Any missing directory will be automatically created for you.
 

     
To use percent literals in an output template use %%. To output to stdout use -o -.
 

     
The current default template is %(title)s-%(id)s.%(ext)s.
 

     
In some cases, you don't want special characters such as 中, spaces, or &, such as when transferring the downloaded filename to a Windows system or the filename through an 8bit-unsafe channel. In these cases, add the --restrict-filenames flag to get a shorter title:
 

     

  
       Output template and Windows batch files
 

     
If you are using an output template inside a Windows batch file then you must escape plain percent characters (%) by doubling, so that -o "%(title)s-%(id)s.%(ext)s" should become -o "%%(title)s-%%(id)s.%%(ext)s". However you should not touch %'s that are not plain characters, e.g. environment variables for expansion should stay intact: -o "C:\%HOMEPATH%\Desktop\%%(title)s.%%(ext)s".
 

     

  
       Output template examples
 

     
Note that on Windows you may need to use double quotes instead of single.
 

     

 
      
$ nextdl --get-filename -o '%(title)s.%(ext)s' BaW_jenozKc
nextdl test video ''_ä↭𝕐.mp4    # All kinds of weird characters

$ nextdl --get-filename -o '%(title)s.%(ext)s' BaW_jenozKc --restrict-filenames
nextdl_test_video_.mp4          # A simple file name

# Download YouTube playlist videos in separate directory indexed by video order in a playlist
$ nextdl -o '%(playlist)s/%(playlist_index)s - %(title)s.%(ext)s' https://www.youtube.com/playlist?list=PLwiyx1dc3P2JR9N8gQaQN_BCvlSlap7re

# Download all playlists of YouTube channel/user keeping each playlist in separate directory:
$ nextdl -o '%(uploader)s/%(playlist)s/%(playlist_index)s - %(title)s.%(ext)s' https://www.youtube.com/user/TheLinuxFoundation/playlists

# Download Udemy course keeping each chapter in separate directory under MyVideos directory in your home
$ nextdl -u user -p password -o '~/MyVideos/%(playlist)s/%(chapter_number)s - %(chapter)s/%(title)s.%(ext)s' https://www.udemy.com/java-tutorial/

# Download entire series season keeping each series and each season in separate directory under C:/MyVideos
$ nextdl -o "C:/MyVideos/%(series)s/%(season_number)s - %(season)s/%(episode_number)s - %(episode)s.%(ext)s" https://videomore.ru/kino_v_detalayah/5_sezon/367617

# Stream the video being downloaded to stdout
$ nextdl -o - BaW_jenozKc

     
 

     

  
       FORMAT SELECTION
 

     
By default nextdl tries to download the best available quality, i.e. if you want the best quality you don't need to pass any special options, nextdl will guess it for you by default.
 

     
But sometimes you may want to download in a different format, for example when you are on a slow or intermittent connection. The key mechanism for achieving this is so-called format selection based on which you can explicitly specify desired format, select formats based on some criterion or criteria, setup precedence and much more.
 

     
The general syntax for format selection is --format FORMAT or shorter -f FORMAT where FORMAT is a selector expression, i.e. an expression that describes format or formats you would like to download.
 

     
tl;dr: navigate me to examples.
 

     
The simplest case is requesting a specific format, for example with -f 22 you can download the format with format code equal to 22. You can get the list of available format codes for particular video using --list-formats or -F. Note that these format codes are extractor specific.
 

     
You can also use a file extension (currently 3gp, aac, flv, m4a, mp3, mp4, ogg, wav, webm are supported) to download the best quality format of a particular file extension served as a single file, e.g. -f webm will download the best quality format with the webm extension served as a single file.
 

     
You can also use special names to select particular edge case formats:
 

     
 
 
      
best: Select the best quality format represented by a single file with video and audio.
 
 
      
worst: Select the worst quality format represented by a single file with video and audio.
 
 
      
bestvideo: Select the best quality video-only format (e.g. DASH video). May not be available.
 
 
      
worstvideo: Select the worst quality video-only format. May not be available.
 
 
      
bestaudio: Select the best quality audio only-format. May not be available.
 
 
      
worstaudio: Select the worst quality audio only-format. May not be available.
 

     
 

     
For example, to download the worst quality video-only format you can use -f worstvideo.
 

     
If you want to download multiple videos and they don't have the same formats available, you can specify the order of preference using slashes. Note that slash is left-associative, i.e. formats on the left hand side are preferred, for example -f 22/17/18 will download format 22 if it's available, otherwise it will download format 17 if it's available, otherwise it will download format 18 if it's available, otherwise it will complain that no suitable formats are available for download.
 

     
If you want to download several formats of the same video use a comma as a separator, e.g. -f 22,17,18 will download all these three formats, of course if they are available. Or a more sophisticated example combined with the precedence feature: -f 136/137/mp4/bestvideo,140/m4a/bestaudio.
 

     
You can also filter the video formats by putting a condition in brackets, as in -f "best[height=720]" (or -f "[filesize>10M]").
 

     
The following numeric meta fields can be used with comparisons <, <=, >, >=, = (equals), != (not equals):
 

     
 
 
      
filesize: The number of bytes, if known in advance
 
 
      
width: Width of the video, if known
 
 
      
height: Height of the video, if known
 
 
      
tbr: Average bitrate of audio and video in KBit/s
 
 
      
abr: Average audio bitrate in KBit/s
 
 
      
vbr: Average video bitrate in KBit/s
 
 
      
asr: Audio sampling rate in Hertz
 
 
      
fps: Frame rate
 

     
 

     
Also filtering work for comparisons = (equals), ^= (starts with), $= (ends with), *= (contains) and following string meta fields:
 

     
 
 
      
ext: File extension
 
 
      
acodec: Name of the audio codec in use
 
 
      
vcodec: Name of the video codec in use
 
 
      
container: Name of the container format
 
 
      
protocol: The protocol that will be used for the actual download, lower-case (http, https, rtsp, rtmp, rtmpe, mms, f4m, ism, http_dash_segments, m3u8, or m3u8_native)
 
 
      
format_id: A short description of the format
 
 
      
language: Language code
 

     
 

     
Any string comparison may be prefixed with negation ! in order to produce an opposite comparison, e.g. !*= (does not contain).
 

     
Note that none of the aforementioned meta fields are guaranteed to be present since this solely depends on the metadata obtained by particular extractor, i.e. the metadata offered by the video hoster.
 

     
Formats for which the value is not known are excluded unless you put a question mark (?) after the operator. You can combine format filters, so -f "[height <=? 720][tbr>500]" selects up to 720p videos (or videos where the height is not known) with a bitrate of at least 500 KBit/s.
 

     
You can merge the video and audio of two formats into a single file using -f 
       
        +
        
        (requires ffmpeg or avconv installed), for example -f bestvideo+bestaudio will download the best video-only format, the best audio-only format and mux them together with ffmpeg/avconv.
 

     
Format selectors can also be grouped using parentheses, for example if you want to download the best mp4 and webm formats with a height lower than 480 you can use -f '(mp4,webm)[height<480]'.
 

     
Since the end of April 2015 and version 2015.04.26, nextdl uses -f bestvideo+bestaudio/best as the default format selection (see #5447, #5456). If ffmpeg or avconv are installed this results in downloading bestvideo and bestaudio separately and muxing them together into a single file giving the best overall quality available. Otherwise it falls back to best and results in downloading the best available quality served as a single file. best is also needed for videos that don't come from YouTube because they don't provide the audio and video in two different files. If you want to only download some DASH formats (for example if you are not interested in getting videos with a resolution higher than 1080p), you can add -f bestvideo[height<=?1080]+bestaudio/best to your configuration file. Note that if you use nextdl to stream to stdout (and most likely to pipe it to your media player then), i.e. you explicitly specify output template as -o -, nextdl still uses -f best format selection in order to start content delivery immediately to your player and not to wait until bestvideo and bestaudio are downloaded and muxed.
 

     
If you want to preserve the old format selection behavior (prior to nextdl 2015.04.26), i.e. you want to download the best available quality media served as a single file, you should explicitly specify your choice with -f best. You may want to add it to the configuration file in order not to type it every time you run nextdl.
 

     

  
       Format selection examples
 

     
Note that on Windows you may need to use double quotes instead of single.
 

     

 
      
# Download best mp4 format available or any other best if no mp4 available
$ nextdl -f 'bestvideo[ext=mp4]+bestaudio[ext=m4a]/best[ext=mp4]/best'

# Download best format available but no better than 480p
$ nextdl -f 'bestvideo[height<=480]+bestaudio/best[height<=480]'

# Download best video only format but no bigger than 50 MB
$ nextdl -f 'best[filesize<50M]'

# Download best format available via direct link over HTTP/HTTPS protocol
$ nextdl -f '(bestvideo+bestaudio/best)[protocol^=http]'

# Download the best video format and the best audio format without merging them
$ nextdl -f 'bestvideo,bestaudio' -o '%(title)s.f%(format_id)s.%(ext)s'

     
 

     
Note that in the last example, an output template is recommended as bestvideo and bestaudio may have the same file name.
 

     

  
       VIDEO SELECTION
 

     
Videos can be filtered by their upload date using the options --date, --datebefore or --dateafter. They accept dates in two formats:
 

     
 
 
      
Absolute dates: Dates in the format YYYYMMDD.
 
 
      
Relative dates: Dates in the format (now|today)[+-][0-9](day|week|month|year)(s)?
 

     
 

     
Examples:
 

     

 
      
# Download only the videos uploaded in the last 6 months
$ nextdl --dateafter now-6months

# Download only the videos uploaded on January 1, 1970
$ nextdl --date 19700101

$ # Download only the videos uploaded in the 200x decade
$ nextdl --dateafter 20000101 --datebefore 20091231

     
 

     

  
       FAQ
 

     

  
       How do I update nextdl?
 

     
If you've followed our manual installation instructions, you can simply run nextdl -U (or, on Linux, sudo nextdl -U).
 

     
If you have used pip, a simple sudo pip install -U nextdl is sufficient to update.
 

     
If you have installed nextdl using a package manager like apt-get or yum, use the standard system update mechanism to update. Note that distribution packages are often outdated. As a rule of thumb, nextdl releases at least once a month, and often weekly or even daily. Simply go to https://nextdl.org to find out the current version. Unfortunately, there is nothing we nextdl developers can do if your distribution serves a really outdated version. You can (and should) complain to your distribution in their bugtracker or support forum.
 

     
As a last resort, you can also uninstall the version installed by your package manager and follow our manual installation instructions. For that, remove the distribution's package, with a line like
 

     

 
      
sudo apt-get remove -y nextdl


     
 

     
Afterwards, simply follow our manual installation instructions:
 

     

 
      
sudo wget https://nextdl.org/downloads/latest/nextdl -O /usr/local/bin/nextdl
sudo chmod a+rx /usr/local/bin/nextdl
hash -r


     
 

     
Again, from then on you'll be able to update with sudo nextdl -U.
 

     

  
       nextdl is extremely slow to start on Windows
 

     
Add a file exclusion for nextdl.exe in Windows Defender settings.
 

     

  
       I'm getting an error Unable to extract OpenGraph title on YouTube playlists
 

     
YouTube changed their playlist format in March 2014 and later on, so you'll need at least nextdl 2014.07.25 to download all YouTube videos.
 

     
If you have installed nextdl with a package manager, pip, setup.py or a tarball, please use that to update. Note that Ubuntu packages do not seem to get updated anymore. Since we are not affiliated with Ubuntu, there is little we can do. Feel free to report bugs to the Ubuntu packaging people - all they have to do is update the package to a somewhat recent version. See above for a way to update.
 

     

  
       I'm getting an error when trying to use output template: error: using output template conflicts with using title, video ID or auto number
 

     
Make sure you are not using -o with any of these options -t, --title, --id, -A or --auto-number set in command line or in a configuration file. Remove the latter if any.
 

     

  
       Do I always have to pass -citw?
 

     
By default, nextdl intends to have the best options (incidentally, if you have a convincing case that these should be different, please file an issue where you explain that). Therefore, it is unnecessary and sometimes harmful to copy long option strings from webpages. In particular, the only option out of -citw that is regularly useful is -i.
 

     

  
       Can you please put the -b option back?
 

     
Most people asking this question are not aware that nextdl now defaults to downloading the highest available quality as reported by YouTube, which will be 1080p or 720p in some cases, so you no longer need the -b option. For some specific videos, maybe YouTube does not report them to be available in a specific high quality format you're interested in. In that case, simply request it with the -f option and nextdl will try to download it.
 

     

  
       I get HTTP error 402 when trying to download a video. What's this?
 

     
Apparently YouTube requires you to pass a CAPTCHA test if you download too much. We're considering to provide a way to let you solve the CAPTCHA, but at the moment, your best course of action is pointing a web browser to the youtube URL, solving the CAPTCHA, and restart nextdl.
 

     

  
       Do I need any other programs?
 

     
nextdl works fine on its own on most sites. However, if you want to convert video/audio, you'll need avconv or ffmpeg. On some sites - most notably YouTube - videos can be retrieved in a higher quality format without sound. nextdl will detect whether avconv/ffmpeg is present and automatically pick the best option.
 

     
Videos or video formats streamed via RTMP protocol can only be downloaded when rtmpdump is installed. Downloading MMS and RTSP videos requires either mplayer or mpv to be installed.
 

     

  
       I have downloaded a video but how can I play it?
 

     
Once the video is fully downloaded, use any video player, such as mpv, vlc or mplayer.
 

     

  
       I extracted a video URL with -g, but it does not play on another machine / in my web browser.
 

     
It depends a lot on the service. In many cases, requests for the video (to download/play it) must come from the same IP address and with the same cookies and/or HTTP headers. Use the --cookies option to write the required cookies into a file, and advise your downloader to read cookies from that file. Some sites also require a common user agent to be used, use --dump-user-agent to see the one in use by nextdl. You can also get necessary cookies and HTTP headers from JSON output obtained with --dump-json.
 

     
It may be beneficial to use IPv6; in some cases, the restrictions are only applied to IPv4. Some services (sometimes only for a subset of videos) do not restrict the video URL by IP address, cookie, or user-agent, but these are the exception rather than the rule.
 

     
Please bear in mind that some URL protocols are not supported by browsers out of the box, including RTMP. If you are using -g, your own downloader must support these as well.
 

     
If you want to play the video on a machine that is not running nextdl, you can relay the video content from the machine that runs nextdl. You can use -o - to let nextdl stream a video to stdout, or simply allow the player to download the files written by nextdl in turn.
 

     

  
       ERROR: no fmt_url_map or conn information found in video info
 

     
YouTube has switched to a new video info format in July 2011 which is not supported by old versions of nextdl. See above for how to update nextdl.
 

     

  
       ERROR: unable to download video
 

     
YouTube requires an additional signature since September 2012 which is not supported by old versions of nextdl. See above for how to update nextdl.
 

     

  
       Video URL contains an ampersand and I'm getting some strange output [1] 2839 or 'v' is not recognized as an internal or external command
 

     
That's actually the output from your shell. Since ampersand is one of the special shell characters it's interpreted by the shell preventing you from passing the whole URL to nextdl. To disable your shell from interpreting the ampersands (or any other special characters) you have to either put the whole URL in quotes or escape them with a backslash (which approach will work depends on your shell).
 

     
For example if your URL is https://www.youtube.com/watch?t=4&v=BaW_jenozKc you should end up with following command:
 

     
nextdl 'https://www.youtube.com/watch?t=4&v=BaW_jenozKc'
 

     
or
 

     
nextdl https://www.youtube.com/watch?t=4\&v=BaW_jenozKc
 

     
For Windows you have to use the double quotes:
 

     
nextdl "https://www.youtube.com/watch?t=4&v=BaW_jenozKc"
 

     

  
       ExtractorError: Could not find JS function u'OF'
 

     
In February 2015, the new YouTube player contained a character sequence in a string that was misinterpreted by old versions of nextdl. See above for how to update nextdl.
 

     

  
       HTTP Error 429: Too Many Requests or 402: Payment Required
 

     
These two error codes indicate that the service is blocking your IP address because of overuse. Usually this is a soft block meaning that you can gain access again after solving CAPTCHA. Just open a browser and solve a CAPTCHA the service suggests you and after that pass cookies to nextdl. Note that if your machine has multiple external IPs then you should also pass exactly the same IP you've used for solving CAPTCHA with --source-address. Also you may need to pass a User-Agent HTTP header of your browser with --user-agent.
 

     
If this is not the case (no CAPTCHA suggested to solve by the service) then you can contact the service and ask them to unblock your IP address, or - if you have acquired a whitelisted IP address already - use the --proxy or --source-address options to select another IP address.
 

     

  
       SyntaxError: Non-ASCII character
 

     
The error
 

     

 
      
File "nextdl", line 2
SyntaxError: Non-ASCII character '\x93' ...


     
 

     
means you're using an outdated version of Python. Please update to Python 2.6 or 2.7.
 

     

  
       What is this binary file? Where has the code gone?
 

     
Since June 2012 (#342) nextdl is packed as an executable zipfile, simply unzip it (might need renaming to nextdl.zip first on some systems) or clone the git repository, as laid out above. If you modify the code, you can run it by executing the __main__.py file. To recompile the executable, run make nextdl.
 

     

  
       The exe throws an error due to missing MSVCR100.dll
 

     
To run the exe you need to install first the Microsoft Visual C++ 2010 Service Pack 1 Redistributable Package (x86).
 

     

  
       On Windows, how should I set up ffmpeg and nextdl? Where should I put the exe files?
 

     
If you put nextdl and ffmpeg in the same directory that you're running the command from, it will work, but that's rather cumbersome.
 

     
To make a different directory work - either for ffmpeg, or for nextdl, or for both - simply create the directory (say, C:\bin, or C:\Users\
       
        \bin
       ), put all the executables directly in there, and then set your PATH environment variable to include that directory.
 

     
From then on, after restarting your shell, you will be able to access both nextdl and ffmpeg (and nextdl will be able to find ffmpeg) by simply typing nextdl or ffmpeg, no matter what directory you're in.
 

     

  
       How do I put downloads into a specific folder?
 

     
Use the -o to specify an output template, for example -o "/home/user/videos/%(title)s-%(id)s.%(ext)s". If you want this for all of your downloads, put the option into your configuration file.
 

     

  
       How do I download a video starting with a -?
 

     
Either prepend https://www.youtube.com/watch?v= or separate the ID from the options with --:
 

     

 
      
nextdl -- -wNyEUrxzFU
nextdl "https://www.youtube.com/watch?v=-wNyEUrxzFU"


     
 

     

  
       How do I pass cookies to nextdl?
 

     
Use the --cookies option, for example --cookies /path/to/cookies/file.txt.
 

     
In order to extract cookies from browser use any conforming browser extension for exporting cookies. For example, Get cookies.txt (for Chrome) or cookies.txt (for Firefox).
 

     
Note that the cookies file must be in Mozilla/Netscape format and the first line of the cookies file must be either # HTTP Cookie File or # Netscape HTTP Cookie File. Make sure you have correct newline format in the cookies file and convert newlines if necessary to correspond with your OS, namely CRLF (\r\n) for Windows and LF (\n) for Unix and Unix-like systems (Linux, macOS, etc.). HTTP Error 400: Bad Request when using --cookies is a good sign of invalid newline format.
 

     
Passing cookies to nextdl is a good way to workaround login when a particular extractor does not implement it explicitly. Another use case is working around CAPTCHA some websites require you to solve in particular cases in order to get access (e.g. YouTube, CloudFlare).
 

     

  
       How do I stream directly to media player?
 

     
You will first need to tell nextdl to stream media to stdout with -o -, and also tell your media player to read from stdin (it must be capable of this for streaming) and then pipe former to latter. For example, streaming to vlc can be achieved with:
 

     

 
      
nextdl -o - "https://www.youtube.com/watch?v=BaW_jenozKcj" | vlc -


     
 

     

  
       How do I download only new videos from a playlist?
 

     
Use download-archive feature. With this feature you should initially download the complete playlist with --download-archive /path/to/download/archive/file.txt that will record identifiers of all the videos in a special file. Each subsequent run with the same --download-archive will download only new videos and skip all videos that have been downloaded before. Note that only successful downloads are recorded in the file.
 

     
For example, at first,
 

     

 
      
nextdl --download-archive archive.txt "https://www.youtube.com/playlist?list=PLwiyx1dc3P2JR9N8gQaQN_BCvlSlap7re"


     
 

     
will download the complete PLwiyx1dc3P2JR9N8gQaQN_BCvlSlap7re playlist and create a file archive.txt. Each subsequent run will only download new videos if any:
 

     

 
      
nextdl --download-archive archive.txt "https://www.youtube.com/playlist?list=PLwiyx1dc3P2JR9N8gQaQN_BCvlSlap7re"


     
 

     

  
       Should I add --hls-prefer-native into my config?
 

     
When nextdl detects an HLS video, it can download it either with the built-in downloader or ffmpeg. Since many HLS streams are slightly invalid and ffmpeg/nextdl each handle some invalid cases better than the other, there is an option to switch the downloader if needed.
 

     
When nextdl knows that one particular downloader works better for a given website, that downloader will be picked. Otherwise, nextdl will pick the best downloader for general compatibility, which at the moment happens to be ffmpeg. This choice may change in future versions of nextdl, with improvements of the built-in downloader and/or ffmpeg.
 

     
In particular, the generic extractor (used when your website is not in the list of supported sites by nextdl cannot mandate one specific downloader.
 

     
If you put either --hls-prefer-native or --hls-prefer-ffmpeg into your configuration, a different subset of videos will fail to download correctly. Instead, it is much better to file an issue or a pull request which details why the native or the ffmpeg HLS downloader is a better choice for your use case.
 

     

  
       Can you add support for this anime video site, or site which shows current movies for free?
 

     
As a matter of policy (as well as legality), nextdl does not include support for services that specialize in infringing copyright. As a rule of thumb, if you cannot easily find a video that the service is quite obviously allowed to distribute (i.e. that has been uploaded by the creator, the creator's distributor, or is published under a free license), the service is probably unfit for inclusion to nextdl.
 

     
A note on the service that they don't host the infringing content, but just link to those who do, is evidence that the service should not be included into nextdl. The same goes for any DMCA note when the whole front page of the service is filled with videos they are not allowed to distribute. A "fair use" note is equally unconvincing if the service shows copyright-protected videos in full without authorization.
 

     
Support requests for services that do purchase the rights to distribute their content are perfectly fine though. If in doubt, you can simply include a source that mentions the legitimate purchase of content.
 

     

  
       How can I speed up work on my issue?
 

     
(Also known as: Help, my important issue not being solved!) The nextdl core developer team is quite small. While we do our best to solve as many issues as possible, sometimes that can take quite a while. To speed up your issue, here's what you can do:
 

     
First of all, please do report the issue at our issue tracker. That allows us to coordinate all efforts by users and developers, and serves as a unified point. Unfortunately, the nextdl project has grown too large to use personal email as an effective communication channel.
 

     
Please read the bug reporting instructions below. A lot of bugs lack all the necessary information. If you can, offer proxy, VPN, or shell access to the nextdl developers. If you are able to, test the issue from multiple computers in multiple countries to exclude local censorship or misconfiguration issues.
 

     
If nobody is interested in solving your issue, you are welcome to take matters into your own hands and submit a pull request (or coerce/pay somebody else to do so).
 

     
Feel free to bump the issue from time to time by writing a small comment ("Issue is still present in nextdl version ...from France, but fixed from Belgium"), but please not more than once a month. Please do not declare your issue as important or urgent.
 

     

  
       How can I detect whether a given URL is supported by nextdl?
 

     
For one, have a look at the list of supported sites. Note that it can sometimes happen that the site changes its URL scheme (say, from https://example.com/video/1234567 to https://example.com/v/1234567 ) and nextdl reports an URL of a service in that list as unsupported. In that case, simply report a bug.
 

     
It is not possible to detect whether a URL is supported or not. That's because nextdl contains a generic extractor which matches all URLs. You may be tempted to disable, exclude, or remove the generic extractor, but the generic extractor not only allows users to extract videos from lots of websites that embed a video from another service, but may also be used to extract video from a service that it's hosting itself. Therefore, we neither recommend nor support disabling, excluding, or removing the generic extractor.
 

     
If you want to find out whether a given URL is supported, simply call nextdl with it. If you get no videos back, chances are the URL is either not referring to a video or unsupported. You can find out which by examining the output (if you run nextdl on the console) or catching an UnsupportedError exception if you run it from a Python program.
 

     

  
       Why do I need to go through that much red tape when filing bugs?
 

     
Before we had the issue template, despite our extensive bug reporting instructions, about 80% of the issue reports we got were useless, for instance because people used ancient versions hundreds of releases old, because of simple syntactic errors (not in nextdl but in general shell usage), because the problem was already reported multiple times before, because people did not actually read an error message, even if it said "please install ffmpeg", because people did not mention the URL they were trying to download and many more simple, easy-to-avoid problems, many of whom were totally unrelated to nextdl.
 

     
nextdl is an open-source project manned by too few volunteers, so we'd rather spend time fixing bugs where we are certain none of those simple problems apply, and where we can be reasonably confident to be able to reproduce the issue without asking the reporter repeatedly. As such, the output of nextdl -v YOUR_URL_HERE is really all that's required to file an issue. The issue template also guides you through some basic steps you can do, such as checking that your version of nextdl is current.
 

     

  
       DEVELOPER INSTRUCTIONS
 

     
Most users do not need to build nextdl and can download the builds or get them from their distribution.
 

     
To run nextdl as a developer, you don't need to build anything either. Simply execute
 

     

 
      
python -m nextdl


     
 

     
To run the test, simply invoke your favorite test runner, or execute a test file directly; any of the following work:
 

     

 
      
python -m unittest discover
python test/test_download.py
nosetests


     
 

     
See item 6 of new extractor tutorial for how to run extractor specific test cases.
 

     
If you want to create a build of nextdl yourself, you'll need
 

     
 
 
      
python
 
 
      
make (only GNU make is supported)
 
 
      
pandoc
 
 
      
zip
 
 
      
nosetests
 

     
 

     

  
       Adding support for a new site
 

     
If you want to add support for a new site, first of all make sure this site is not dedicated to copyright infringement. nextdl does not support such sites thus pull requests adding support for them will be rejected.
 

     
After you have ensured this site is distributing its content legally, you can follow this quick list (assuming your service is called yourextractor):
 

     
 
 
      
 
Fork this repository
 
 
 
      
 
Check out the source code with:
 
  
       

   
        
 git clone [email protected]:YOUR_GITHUB_USERNAME/nextdl.git

  
       
 
 
 
      
 
Start a new git branch with
 
  
       

   
        
 cd nextdl
 git checkout -b yourextractor

  
       
 
 
 
      
 
Start with this simple template and save it to nextdl/extractor/yourextractor.py:
 
  
       

        ]*>([^<]+)<', webpage, 'uploader', fatal=False),
            # TODO more properties (see nextdl/extractor/common.py)
        }">
   
        
# coding: utf-8
from __future__ import unicode_literals

from .common import InfoExtractor


class YourExtractorIE(InfoExtractor):
    _VALID_URL = r'https?://(?:www\.)?yourextractor\.com/watch/(?P
          
           [0-9]+)'
          
    _TEST = {
        'url': 'https://yourextractor.com/watch/42',
        'md5': 'TODO: md5 sum of the first 10241 bytes of the video file (use --test)',
        'info_dict': {
            'id': '42',
            'ext': 'mp4',
            'title': 'Video title goes here',
            'thumbnail': r're:^https?://.*\.jpg$',
            # TODO more properties, either as:
            # * A value
            # * MD5 checksum; start the string with md5:
            # * A regular expression; start the string with re:
            # * Any Python type (for example int or float)
        }
    }

    def _real_extract(self, url):
        video_id = self._match_id(url)
        webpage = self._download_webpage(url, video_id)

        # TODO more code goes here, for example ...
        title = self._html_search_regex(r'
(.+?)
', webpage, 'title')

        return {
            'id': video_id,
            'title': title,
            'description': self._og_search_description(webpage),
            'uploader': self._search_regex(r'
          
           ]+id="uploader"[^>]*>([^<]+)<'
          , webpage, 'uploader', fatal=False),
            # TODO more properties (see nextdl/extractor/common.py)
        }
  
       
 
 
 
      
 
Add an import in nextdl/extractor/extractors.py.
 
 
 
      
 
Run python test/test_download.py TestDownload.test_YourExtractor. This should fail at first, but you can continually re-run it until you're done. If you decide to add more than one test, then rename _TEST to _TESTS and make it into a list of dictionaries. The tests will then be named TestDownload.test_YourExtractor, TestDownload.test_YourExtractor_1, TestDownload.test_YourExtractor_2, etc. Note that tests with only_matching key in test's dict are not counted in.
 
 
 
      
 
Have a look at nextdl/extractor/common.py for possible helper methods and a detailed description of what your extractor should and may return. Add tests and code for as many as you want.
 
 
 
      
 
Make sure your code follows nextdl coding conventions and check the code with flake8:
 
  
       

   
        
 $ flake8 nextdl/extractor/yourextractor.py

  
       
 
 
 
      
 
Make sure your code works under all Python versions claimed supported by nextdl, namely 2.6, 2.7, and 3.2+.
 
 
 
      
 
When the tests pass, add the new files and commit them and push the result, like this:
 
  
       

   
        
$ git add nextdl/extractor/extractors.py
$ git add nextdl/extractor/yourextractor.py
$ git commit -m '[yourextractor] Add new extractor'
$ git push origin yourextractor

  
       
 
 
 
      
 
Finally, create a pull request. We'll then review and merge it.
 
 

     
 

     
In any case, thank you very much for your contributions!
 

     

  
       nextdl coding conventions
 

     
This section introduces a guide lines for writing idiomatic, robust and future-proof extractor code.
 

     
Extractors are very fragile by nature since they depend on the layout of the source data provided by 3rd party media hosters out of your control and this layout tends to change. As an extractor implementer your task is not only to write code that will extract media links and metadata correctly but also to minimize dependency on the source's layout and even to make the code foresee potential future changes and be ready for that. This is important because it will allow the extractor not to break on minor layout changes thus keeping old nextdl versions working. Even though this breakage issue is easily fixed by emitting a new version of nextdl with a fix incorporated, all the previous versions become broken in all repositories and distros' packages that may not be so prompt in fetching the update from us. Needless to say, some non rolling release distros may never receive an update at all.
 

     

  
       Mandatory and optional metafields
 

     
For extraction to work nextdl relies on metadata your extractor extracts and provides to nextdl expressed by an information dictionary or simply info dict. Only the following meta fields in the info dict are considered mandatory for a successful extraction process by nextdl:
 

     
 
 
      
id (media identifier)
 
 
      
title (media title)
 
 
      
url (media download URL) or formats
 

     
 

     
In fact only the last option is technically mandatory (i.e. if you can't figure out the download location of the media the extraction does not make any sense). But by convention nextdl also treats id and title as mandatory. Thus the aforementioned metafields are the critical data that the extraction does not make any sense without and if any of them fail to be extracted then the extractor is considered completely broken.
 

     
Any field apart from the aforementioned ones are considered optional. That means that extraction should be tolerant to situations when sources for these fields can potentially be unavailable (even if they are always available at the moment) and future-proof in order not to break the extraction of general purpose mandatory fields.
 

     

  
       Example
 

     
Say you have some source dictionary meta that you've fetched as JSON with HTTP request and it has a key summary:
 

     

 
      
meta = self._download_json(url, video_id)

     
 

     
Assume at this point meta's layout is:
 

     

 
      
{
    ...
    "summary": "some fancy summary text",
    ...
}

     
 

     
Assume you want to extract summary and put it into the resulting info dict as description. Since description is an optional meta field you should be ready that this key may be missing from the meta dict, so that you should extract it like:
 

     

 
      
description = meta.get('summary')  # correct

     
 

     
and not like:
 

     

 
      
description = meta['summary']  # incorrect

     
 

     
The latter will break extraction process with KeyError if summary disappears from meta at some later time but with the former approach extraction will just go ahead with description set to None which is perfectly fine (remember None is equivalent to the absence of data).
 

     
Similarly, you should pass fatal=False when extracting optional data from a webpage with _search_regex, _html_search_regex or similar methods, for instance:
 

     

      ]*>([^<]+)<',
    webpage, 'description', fatal=False)">
 
      
description = self._search_regex(
    r'
        
         ]+id="title"[^>]*>([^<]+)<'
        ,
    webpage, 'description', fatal=False)

     
 

     
With fatal set to False if _search_regex fails to extract description it will emit a warning and continue extraction.
 

     
You can also pass default=
       , for example:
 

     

      ]*>([^<]+)<',
    webpage, 'description', default=None)">
 
      
description = self._search_regex(
    r'
        
         ]+id="title"[^>]*>([^<]+)<'
        ,
    webpage, 'description', default=None)

     
 

     
On failure this code will silently continue the extraction with description set to None. That is useful for metafields that may or may not be present.
 

     

  
       Provide fallbacks
 

     
When extracting metadata try to do so from multiple sources. For example if title is present in several places, try extracting from at least some of them. This makes it more future-proof in case some of the sources become unavailable.
 

     

  
       Example
 

     
Say meta from the previous example has a title and you are about to extract it. Since title is a mandatory meta field you should end up with something like:
 

     

 
      
title = meta['title']

     
 

     
If title disappears from meta in future due to some changes on the hoster's side the extraction would fail since title is mandatory. That's expected.
 

     
Assume that you have some another source you can extract title from, for example og:title HTML meta of a webpage. In this case you can provide a fallback scenario:
 

     

 
      
title = meta.get('title') or self._og_search_title(webpage)

     
 

     
This code will try to extract from meta first and if it fails it will try extracting og:title from a webpage.
 

     

  
       Regular expressions
 

     

  
       Don't capture groups you don't use
 

     
Capturing group must be an indication that it's used somewhere in the code. Any group that is not used must be non capturing.
 

     

  
       Example
 

     
Don't capture id attribute name here since you can't use it for anything anyway.
 

     
Correct:
 

     

 
      
r'(?:id|ID)=(?P
        
         \d+)'
        

     
 

     
Incorrect:
 

     

 
      
r'(id|ID)=(?P
        
         \d+)'
        

     
 

     

  
       Make regular expressions relaxed and flexible
 

     
When using regular expressions try to write them fuzzy, relaxed and flexible, skipping insignificant parts that are more likely to change, allowing both single and double quotes for quoted values and so on.
 

     

  
       Example
 

     
Say you need to extract title from the following HTML code:
 

     

      some fancy title">
 
      
<span style="position: absolute; left: 910px; width: 90px; float: right; z-index: 9999;" class="title">some fancy titlespan>

     
 

     
The code for that task should look similar to:
 

     

      ]*>([^<]+)', webpage, 'title')">
 
      
title = self._search_regex(
    r'
        
         ]+class="title"[^>]*>([^<]+)'
        , webpage, 'title')

     
 

     
Or even better:
 

     

      ]*>(?P
      ', webpage, 'title')">
 
      
title = self._html_search_regex(r'', webpage, 'title')

     
 

     
Incorrect:
 

     

 
      
TITLE_RE = r''
# ...some lines of code...
title = self._html_search_regex(TITLE_RE, webpage, 'title')

     
 

     

  
       Collapse fallbacks
 

     
Multiple fallback values can quickly become unwieldy. Collapse multiple fallback values into a single expression via a list of patterns.
 

     

  
       Example
 

     
Good:
 

     

 
      
description = self._html_search_meta(
    ['og:description', 'description', 'twitter:description'],
    webpage, 'description', default=None)

     
 

     
Unwieldy:
 

     

 
      
description = (
    self._og_search_description(webpage, default=None)
    or self._html_search_meta('description', webpage, default=None)
    or self._html_search_meta('twitter:description', webpage, default=None))

     
 

     
Methods supporting list of patterns are: _search_regex, _html_search_regex, _og_search_property, _html_search_meta.
 

     

  
       Trailing parentheses
 

     
Always move trailing parentheses after the last argument.
 

     

  
       Example
 

     
Correct:
 

     

 
      
    lambda x: x['ResultSet']['Result'][0]['VideoUrlSet']['VideoUrl'],
    list)

     
 

     
Incorrect:
 

     

 
      
    lambda x: x['ResultSet']['Result'][0]['VideoUrlSet']['VideoUrl'],
    list,
)

     
 

     

  
       Use convenience conversion and parsing functions
 

     
Wrap all extracted numeric data into safe functions from nextdl/utils.py: int_or_none, float_or_none. Use them for string to number conversions as well.
 

     
Use url_or_none for safe URL processing.
 

     
Use try_get for safe metadata extraction from parsed JSON.
 

     
Use unified_strdate for uniform upload_date or any YYYYMMDD meta field extraction, unified_timestamp for uniform timestamp extraction, parse_filesize for filesize extraction, parse_count for count meta fields extraction, parse_resolution, parse_duration for duration extraction, parse_age_limit for age_limit extraction.
 

     
Explore nextdl/utils.py for more useful convenience functions.
 

     

  
       More examples
 

     

  
       Safely extract optional description from parsed JSON
 

     

 
      
description = try_get(response, lambda x: x['result']['video'][0]['summary'], compat_str)

     
 

     

  
       Safely extract more optional metadata
 

     

 
      
video = try_get(response, lambda x: x['result']['video'][0], dict) or {}
description = video.get('summary')
duration = float_or_none(video.get('durationMs'), scale=1000)
view_count = int_or_none(video.get('views'))

     
 

     

  
       EMBEDDING nextdl
 

     
nextdl makes the best effort to be a good command-line program, and thus should be callable from any programming language. If you encounter any problems parsing its output, feel free to create a report.
 

     
From a Python program, you can embed nextdl in a more powerful fashion, like this:
 

     

 
      
from __future__ import unicode_literals
import nextdl

ydl_opts = {}
with nextdl.nextdl(ydl_opts) as ydl:
    ydl.download(['https://www.youtube.com/watch?v=BaW_jenozKc'])

     
 

     
Most likely, you'll want to use various options. For a list of options available, have a look at nextdl/nextdl.py. For a start, if you want to intercept nextdl's output, set a logger object.
 

     
Here's a more complete example of a program that outputs only errors (and a short message after the download is finished), and downloads/converts the video to an mp3 file:
 

     

 
      
from __future__ import unicode_literals
import nextdl


class MyLogger(object):
    def debug(self, msg):
        pass

    def warning(self, msg):
        pass

    def error(self, msg):
        print(msg)


def my_hook(d):
    if d['status'] == 'finished':
        print('Done downloading, now converting ...')


ydl_opts = {
    'format': 'bestaudio/best',
    'postprocessors': [{
        'key': 'FFmpegExtractAudio',
        'preferredcodec': 'mp3',
        'preferredquality': '192',
    }],
    'logger': MyLogger(),
    'progress_hooks': [my_hook],
}
with nextdl.nextdl(ydl_opts) as ydl:
    ydl.download(['https://www.youtube.com/watch?v=BaW_jenozKc'])

     
 

     

  
       BUGS
 

     
Bugs and suggestions should be reported at: https://github.com/nextdl/nextdl/issues. Unless you were prompted to or there is another pertinent reason (e.g. GitHub fails to accept the bug report), please do not send bug reports via personal email. For discussions, join us in the IRC channel #nextdl on freenode (webchat).
 

     
Please include the full output of nextdl when run with -v, i.e. add -v flag to your command line, copy the whole output and post it in the issue body wrapped in ``` for better formatting. It should look similar to this:
 

     

 
      
$ nextdl -v 
        
         
[debug] System config: []
[debug] User config: []
[debug] Command-line args: [u'-v', u'https://www.youtube.com/watch?v=BaW_jenozKcj']
[debug] Encodings: locale cp1251, fs mbcs, out cp866, pref cp1251
[debug] nextdl version 2015.12.06
[debug] Git HEAD: 135392e
[debug] Python version 2.6.6 - Windows-2003Server-5.2.3790-SP2
[debug] exe versions: ffmpeg N-75573-g1d0487f, ffprobe N-75573-g1d0487f, rtmpdump 2.4
[debug] Proxy map: {}
...

        

     
 

     
Do not post screenshots of verbose logs; only plain text is acceptable.
 

     
The output (including the first lines) contains important debugging information. Issues without the full output are often not reproducible and therefore do not get solved in short order, if ever.
 

     
Please re-read your issue once again to avoid a couple of common mistakes (you can and should use this as a checklist):
 

     

  
       Is the description of the issue itself sufficient?
 

     
We often get issue reports that we cannot really decipher. While in most cases we eventually get the required information after asking back multiple times, this poses an unnecessary drain on our resources. Many contributors, including myself, are also not native speakers, so we may misread some parts.
 

     
So please elaborate on what feature you are requesting, or what bug you want to be fixed. Make sure that it's obvious
 

     
 
 
      
What the problem is
 
 
      
How it could be fixed
 
 
      
How your proposed solution would look like
 

     
 

     
If your report is shorter than two lines, it is almost certainly missing some of these, which makes it hard for us to respond to it. We're often too polite to close the issue outright, but the missing info makes misinterpretation likely. As a committer myself, I often get frustrated by these issues, since the only possible way for me to move forward on them is to ask for clarification over and over.
 

     
For bug reports, this means that your report should contain the complete output of nextdl when called with the -v flag. The error message you get for (most) bugs even says so, but you would not believe how many of our bug reports do not contain this information.
 

     
If your server has multiple IPs or you suspect censorship, adding --call-home may be a good idea to get more diagnostics. If the error is ERROR: Unable to extract ... and you cannot reproduce it from multiple countries, add --dump-pages (warning: this will yield a rather large output, redirect it to the file log.txt by adding >log.txt 2>&1 to your command-line) or upload the .dump files you get when you add --write-pages somewhere.
 

     
Site support requests must contain an example URL. An example URL is a URL you might want to download, like https://www.youtube.com/watch?v=BaW_jenozKc. There should be an obvious video present. Except under very special circumstances, the main page of a video service (e.g. https://www.youtube.com/) is not an example URL.
 

     

  
       Are you using the latest version?
 

     
Before reporting any issue, type nextdl -U. This should report that you're up-to-date. About 20% of the reports we receive are already fixed, but people are using outdated versions. This goes for feature requests as well.
 

     

  
       Is the issue already documented?
 

     
Make sure that someone has not already opened the issue you're trying to open. Search at the top of the window or browse the GitHub Issues of this repository. If there is an issue, feel free to write something along the lines of "This affects me as well, with version 2015.01.01. Here is some more information on the issue: ...". While some issues may be old, a new post into them often spurs rapid activity.
 

     

  
       Why are existing options not enough?
 

     
Before requesting a new feature, please have a quick peek at the list of supported options. Many feature requests are for features that actually exist already! Please, absolutely do show off your work in the issue report and detail how the existing similar options do not solve your problem.
 

     

  
       Is there enough context in your bug report?
 

     
People want to solve problems, and often think they do us a favor by breaking down their larger problems (e.g. wanting to skip already downloaded files) to a specific request (e.g. requesting us to look whether the file exists before downloading the info page). However, what often happens is that they break down the problem into two steps: One simple, and one impossible (or extremely complicated one).
 

     
We are then presented with a very complicated request when the original problem could be solved far easier, e.g. by recording the downloaded video IDs in a separate file. To avoid this, you must include the greater context where it is non-obvious. In particular, every feature request that does not consist of adding support for a new site should contain a use case scenario that explains in what situation the missing feature would be useful.
 

     

  
       Does the issue involve one problem, and one problem only?
 

     
Some of our users seem to think there is a limit of issues they can or should open. There is no limit of issues they can or should open. While it may seem appealing to be able to dump all your issues into one ticket, that means that someone who solves one of your issues cannot mark the issue as closed. Typically, reporting a bunch of issues leads to the ticket lingering since nobody wants to attack that behemoth, until someone mercifully splits the issue into multiple ones.
 

     
In particular, every site support request issue should only pertain to services at one site (generally under a common domain, but always using the same backend technology). Do not request support for vimeo user videos, White house podcasts, and Google Plus pages in the same issue. Also, make sure that you don't post bug reports alongside feature requests. As a rule of thumb, a feature request does not include outputs of nextdl that are not immediately related to the feature at hand. Do not post reports of a network error alongside the request for a new video service.
 

     

  
       Is anyone going to need the feature?
 

     
Only post features that you (or an incapacitated friend you can personally talk to) require. Do not post features because they seem like a good idea. If they are really useful, they will be requested by someone who requires them.
 

     

  
       Is your question about nextdl?
 

     
It may sound strange, but some bug reports we receive are completely unrelated to nextdl and relate to a different, or even the reporter's own, application. Please make sure that you are actually using nextdl. If you are using a UI for nextdl, report the bug to the maintainer of the actual application providing the UI. On the other hand, if your UI for nextdl fails in some way you believe is related to nextdl, by all means, go ahead and report the bug.
 

     

  
       COPYRIGHT
 

     
nextdl is under the MIT License.