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title | description | author | cover | date | draft | toc | categories | tags | ||||||
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Replacing YouTube & Invidious | Simple script I created to download YouTube videos | Amolith | /assets/pngs/download-video.png | 2020-08-03T05:43:37-04:00 | false | true |
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Omar Roth, the developer of Invidious, recently wrote a blog post about Stepping away from open source. While I never used the official instance, I thought this was a good opportunity to create a tool that downloads videos from YouTubers I'm subscribed to so I can watch them offline in whatever manner I prefer.
To that end, youtube-dl is by far the most reliable and versatile option. Having been around since before 20081, I don't think the project is going anywhere. MPV is my media player of choice and it relies on youtube-dl for watching online content from Twitch to YouTube to PornHub to much more.
Conveniently, youtube-dl comes with all of the tools and flags needed
for exactly this purpose so scripting and automating it is incredibly
easy. Taking a look at man youtube-dl
reveals a plethora of options
but only a few are necessary.
Preventing duplicates
The main thing when downloading an entire channel is ensuring the same
video isn't downloaded more than once. --download-archive
will save the
IDs of all the videos downloaded to prevent them from being downloaded
again. All that's required is a file path at which to store the list.
--download-archive .archives/<channel>.txt
Selecting quality
By default, youtube-dl downloads the single file with the best quality
audio and video so it doesn't need to mux2 them together after.
However, I prefer to have the highest possibly quality and don't mind
waiting a few seconds longer for FFmpeg to combine audio and video
files. --format
lets the user decide which format they prefer and
whether they want to focus on storage efficiency or quality. The basic
options are best
, worst
, bestvideo
, and bestaudio
. These will
download a single file that is the highest or lowest quality of both
video/audio or video-only/audio-only. There are a lot of other options
for more fine-grained control over what to look for but, as I mentioned,
I want the highest video and the highest quality audio so I use
bestvideo+bestaudio
. After downloading both of those files, they will
be muxed together.
--format bestvideo+bestaudio
Embedding subtitles
I enjoy subtitles but I know many people don't so this section can certainly be ignored.
There are a few options for fetching and embedding subtitles. To get
"real" subtitles that someone transcribed manually, use --write-sub
.
For YouTube's auto-generated subtitles that may or may not be horribly
inaccurate, use --write-auto-sub
. For selecting the language,
--sub-lang <language-code>
, for embedding them, --embed-subs
, and
for selecting the format, --sub-format <desired-format>
. I like using
SRT files so I have that first with best
beside it like so:
--sub-format srt/best
. SRT is preferred but, if unavailable, whatever
other highest-quality format will be used and embedded instead.
--write-sub --write-auto-sub --sub-format srt/best --sub-lang en --embed-subs
Limiting downloads
When switching to this method, the initial download will pull all of a
channel's videos. I certainly don't want this so they should be limited
in some way. --dateafter
and --playlist-end
serve very nicely. The
former will only download videos published after a certain date and
the latter will only download X number of videos.
--dateafter 20200801 --playlist-end 5
EDIT: A reader sent me an email with this improvement to the archive
functionality. Rather than checking the last five days of videos to see
if they've already been downloaded, this snippet will check when the
archive file was last edited and use that as the --dateafter
parameter, making the script a bit more efficient.
AFTER=$(date -r .archives/"$1".txt +%Y%m%d 2>/dev/null || date +%Y%m%d)
--dateafter $AFTER --playlist-end 5
Naming format
The final parameter to look at is how to name the files once they're
downloaded. --output
provides templating functionality and there are a
lot of options. For this use, an acceptable template might be
something like Channel/Title.ext
. In youtube-dl's templating format,
that's "%(uploader)s/%(title)s.%(ext)s"
.
--output "%(uploader)s/%(title)s.%(ext)s"
Getting notifications
I don't yet have a good method for getting notifications when there are
new videos but there is a simple way to get notified when the script
is finished running. notify-send
is one of the easiest and has pretty
simple syntax as well: the first string is the notification summary and
the second is a longer description. You can optionally pass an icon name
to make it look a little better.
notify-send -i video-x-generic "Downloads finished" "Check the YouTube folder for new videos"
For some reason, I don't get icons when the generic name is specified
but I know the command will work on most systems. On mine, I have to
pass the path to the icon file I want: -i /usr/share/icons/Suru++-Dark/apps/64/video.svg
Writing the script
I want to store the videos in ~/Videos/YouTube
and I want the archive
records stored in .archives
so the first line (after the shebang3)
creates those directories if they don't already exist and the second
enters the YouTube
folder.
mkdir -p "$HOME/Videos/YouTube/.archives"
cd "$HOME/Videos/YouTube"
From here, a way to reuse the youtube-dl command is necessary so parameters can be changed in one place and they'll apply to all channels. Functions are intended for exactly this purpose and are formatted like so:
functionName () {
# Code here
}
I've named the function dl
so mine looks like this:
dl () {
AFTER=$(date -r .archives/"$1".txt +%Y%m%d 2>/dev/null || \
date +%Y%m%d)
youtube-dl --download-archive .archives/"$1".txt -f \
bestvideo+bestaudio --dateafter 20200801 --write-sub \
--write-auto-sub --sub-format srt/best --sub-lang en \
--embed-subs -o "%(uploader)s/%(title)s.%(ext)s" \
--playlist-end 5 "$2"
sleep 5
}
Because it's in a function that's called repeatedly, the AFTER
variable will be reevaluated each time using a different archive file to
ensure no videos are missed. The backslashes at the end (\
) tell bash
that it's a single command spanning multiple lines. At the bottom,
sleep
just waits 5 seconds before downloading the next channel. It's
unlikely that YouTube will ratelimit a residential address for this but
it is still possible. Waiting a bit before continuing reduces the
likelihood further.
Note the use of "$1"
and "$2"
in the archive path and at the very
end of the youtube-dl command. This lets the user define what the
archive file should be named and what channel to download videos from. A
line using the function would be something like:
dl linustechtips https://www.youtube.com/user/LinusTechTips
The result would be this directory structure:
YouTube
|-- .archives
| \-- linustechtips.txt
\-- Linus Tech Tips
\-- They still make MP3 players.mkv
The last line is the notification command:
notify-send -i video-x-generic "Downloads finished" "Check the YouTube folder for new videos"
Finished script
This the script I have in use right now.
#!/bin/bash
mkdir -p "$HOME/Videos/YouTube/.archives"
cd "$HOME/Videos/YouTube"
dl () {
AFTER=$(date -r .archives/"$1".txt +%Y%m%d 2>/dev/null || \
date +%Y%m%d)
youtube-dl --download-archive .archives/"$1".txt -f \
bestvideo+bestaudio --dateafter $AFTER --write-sub \
--write-auto-sub --sub-format srt/best --sub-lang en \
--embed-subs -o "%(uploader)s/%(title)s.%(ext)s" \
--playlist-end 5 "$2"
sleep 5
}
dl vsauce https://www.youtube.com/user/Vsauce
dl avikaplan https://www.youtube.com/user/AviKaplanMusic
dl robscallon https://www.youtube.com/user/robs70986987
dl logosbynick https://www.youtube.com/channel/UCEQXp_fcqwPcqrzNtWJ1w9w
dl andrewhuang https://www.youtube.com/user/songstowearpantsto
dl brandonacker https://www.youtube.com/user/brandonacker
dl lastweektonight https://www.youtube.com/user/LastWeekTonight
dl bingingwithbabish https://www.youtube.com/user/bgfilms
notify-send --icon /usr/share/icons/Suru++-Dark/apps/64/video.svg "Downloads finished" "Check the YouTube folder for new videos"
Automation
This is a very simple process.
- Store your script wherever you want but take note of the directory.
- Run
crontab -e
- If you don't already have a cron utility installed, try
cronie
. It should be in most repos.
- If you don't already have a cron utility installed, try
- Paste and edit:
0 */6 * * * /home/user/path/to/script.sh
- Save
- Exit
- ???
- Profit
The pasted line runs the script every 6th hour of every day, every week,
every month, and every year. To change the frequency just run crontab -e
, edit the line, and save. Crontab
Generator or Crontab
Guru might be useful if the syntax is confusing.
Have fun!
Edits
- Synchronised
--dateafter
parameter with last modified timestamp of the archive file — thank you Dominic!
-
The first commit for the current youtube-dl repository was made on 21 July 2008 and it references "the new youtube-dl", which suggests versions prior. ↩︎
-
In the digital media world, muxing is process of combining two or more files into one. This might be a video track, multiple audio tracks, and/or subtitle tracks. ↩︎
-
A shebang is a sequence of characters that tell your program loader what interpreter to use.
#!/bin/bash
is what you would use if it's a bash script. To use a Python interpreter,#!/usr/bin/env python
will use the program search path to find the appropriate executable. ↩︎