Awesome
ytcast
cast YouTube videos to your smart TV from command-line.
this program does roughly the same thing as the "Play on TV" button that appears on the player bar when you visit youtube.com with Chrome or when you use the YouTube smartphone app:
(the feature is also described here).
I don't use Chrome as my daily driver because of reasons and I tend to use my
smartphone the least as possible when I'm at home... but still I want the "Play
on TV" functionality to watch videos on the big television screen without having
to search them with the remote! this is why I wrote this tool. also my computing
workflow is "command-line centric" and ytcast
fits well in my toolbox (see
other tools).
(video demo on YouTube if above doesn't play).
contents
usage
- the computer running
ytcast
and the target device must be on the same network. - the target device must support the DIAL protocol (see how it works).
- the target device must have the YouTube on TV app already installed.
run ytcast -h
for the full usage, here I'll show the basic options.
the -d
(device) option selects the target device matching by name, hostname
(ip), or unique service name:
$ ytcast -d fire https://www.youtube.com/watch?v=dQw4w9WgXcQ
to see the already discovered (cached) devices use the -l
(list) option:
$ ytcast -l
28bc7426 192.168.1.35 "FireTVStick di Marco" cached lastused
d0881fbe 192.168.1.227 "[LG] webOS TV UM7100PLB" cached
to update the devices cache use the -s
(search) option (it's implicit when the
cache is empty or when -d
doesn't match anything in the cache):
$ ytcast -s
28bc7426 192.168.1.35 "FireTVStick di Marco" lastused
d0881fbe 192.168.1.227 "[LG] webOS TV UM7100PLB" cached
if your target device doesn't show up, you can try increasing the search timeout
with the -t
(timeout) option to give the device more time to respond to the
query:
$ ytcast -s -t 10s
28bc7426 192.168.1.35 "FireTVStick di Marco" lastused
d0881fbe 192.168.1.227 "[LG] webOS TV UM7100PLB" cached
remember that the computer and the target device must be on the same network.
if it doesn't show up after several tries, you may consider using the -pair
option to skip the discovery process altogether. this adds some limitations
though, see workarounds.
to cast to the last used device use the -p
option:
$ ytcast -p https://www.youtube.com/watch?v=dQw4w9WgXcQ
when no url is passed in the arguments, ytcast
reads video urls (or ids) from
stdin
one per line:
$ ytcast -d lg < watchlist
this makes it easy to combine ytcast
with other tools like ytfzf
or my
ytfzf
clone ytsearch
.
to see what's going on under the hood use the -verbose
option:
$ ytsearch fireplace 10 hours | ytcast -d lg -verbose
21:13:08 ytcast.go:82: ytcast v0.1.0-6-g8e6daeb
21:13:08 ytcast.go:168: mkdir -p /home/marco/.cache/ytcast
21:13:08 ytcast.go:177: loading cache /home/marco/.cache/ytcast/ytcast.json
21:13:08 ytcast.go:319: reading videos from stdin
21:13:15 dial.go:153: GET http://192.168.1.227:1754/
21:13:15 dial.go:153: GET http://192.168.1.227:36866/apps/YouTube
21:13:15 ytcast.go:293: "YouTube" is stopped on "[LG] webOS TV UM7100PLB"
21:13:15 ytcast.go:306: launching "YouTube" on "[LG] webOS TV UM7100PLB"
21:13:15 dial.go:153: POST http://192.168.1.227:36866/apps/YouTube
21:13:18 dial.go:153: GET http://192.168.1.227:36866/apps/YouTube
21:13:18 ytcast.go:293: "YouTube" is running on "[LG] webOS TV UM7100PLB"
21:13:18 ytcast.go:358: requesting YouTube Lounge to play [cdKop6aixVE] on "[LG] webOS TV UM7100PLB"
21:13:18 remote.go:233: POST https://www.youtube.com/api/lounge/bc/bind
21:13:18 remote.go:233: POST https://www.youtube.com/api/lounge/bc/bind
21:13:18 ytcast.go:197: saving cache /home/marco/.cache/ytcast/ytcast.json
(please run with -verbose
and attach the log when reporting an issue).
install
you can get a pre-compiled binary from the latest release assets and copy
it somewhere in your $PATH
.
here a quick and dirty one-liner script to do it fast on unix-like systems
(adjust target
and dir
to your needs, lookup available targets in the
latest release assets):
(target="linux-amd64"; dir="$HOME/bin"; \
wget -O - https://api.github.com/repos/MarcoLucidi01/ytcast/releases/latest \
| jq -r --arg target "$target" '.assets[] | select(.name | match("checksums|"+$target)) | .browser_download_url' \
| wget -i - \
&& sha256sum -c --ignore-missing ytcast-v*-checksums.txt \
&& tar -vxf ytcast-v*"$target.tar.gz" \
&& install -m 755 ytcast-v*"$target/ytcast" "$dir")
if you run Arch Linux (btw I don't) you can get ytcast-bin
from the AUR
(many thanks to the maintainer)!
if your os or architecture are not available, or you want to get the latest
changes from master
, you can compile from source. a go
compiler and make
are required for building and installing:
$ git clone https://github.com/MarcoLucidi01/ytcast.git
...
$ cd ytcast
$ make install
...
make install
installs in /usr/local/bin
by default, you can change PREFIX
if you want, for example I like to keep my binaries inside $HOME/bin
so I
usually install with:
$ make install PREFIX=$HOME
...
go build -trimpath -tags netgo,osusergo -ldflags="-w -s -X main.progVersion=v0.5.0-3-gd513b8e" -o ytcast
mkdir -p /home/marco/bin
install -m 755 ytcast /home/marco/bin
to uninstall run make uninstall
(with the same PREFIX
used for install
).
how it works
I've always been curious to know how my phone can find my TV on my home network and instruct it to start the YouTube on TV app and play a video right away without basically any manual pairing.
I did some research and found about this nice little protocol called DIAL (DIscovery And Launch) developed by Netflix and Google which does the initial part i.e. allows second-screen devices (phone, laptop, etc..) to discover and launch apps on first-screen devices (TV, set-top, blu-ray, etc..). there is a 40 pages specification and a reference implementation for this protocol.
the discovery part of DIAL is actually performed using another protocol, SSDP (Simple Service Discovery Protocol), which in turn is part of UPnP.
all this is not enough to play videos. once the YouTube on TV app is started by DIAL, we need some other way to "tell" the app which video we want to play (actually DIAL allows to pass parameters to an app you want to launch, but this mechanism is not used by the YouTube on TV app anymore).
after a little more research, I found about the YouTube Lounge api which is used
by Chrome and the YouTube smartphone app to remotely control the YouTube on TV
app. it allows to start playing videos, pause, unpause, skip, add videos to the
queue and more. the api is not documented and understanding how it works
it's not an easy and fun job. luckily lots of people have already reverse
engineered the thing (see THANKS) so all I had to do was taking the bits I
needed to build ytcast
.
the bridge between DIAL and YouTube Lounge api is the screenId
which as you
can imagine is an identifier for your "screen" (TV app). DIAL allows to get
information about the current "state" of an app on a particular device. some
fields of this state are required by DIAL, other fields are app specific (called
additional data). screenId
is a YouTube specific field that can be used to get
a token from the YouTube Lounge api: with that token we can control the YouTube
on TV app via api calls.
putting all together, what ytcast
does is:
- search DIAL enabled devices on the local network (SSDP)
- get the state of the YouTube on TV app on the target device (DIAL)
- if the app is stopped, start it (DIAL)
- get the
screenId
of the app (DIAL) - get a token for that
screenId
(Lounge) - call the api's "play video endpoint" passing the token and the video urls to play (Lounge)
(there is a "devices cache" involved so ytcast
won't necessarily do all these
steps every time, also if the target device is turned off, ytcast
tries to
wake it up with Wake-on-Lan).
as you may have already guessed, all this can stop working at any time! the
weakest point is the YouTube Lounge api since it's not documented and
ytcast
depends heavily on it. moreover, ytcast
may not work at all on your
setup! I use and test ytcast
with 2 devices:
- Amazon Fire TV Stick
- LG Smart TV running WebOS
that's all I have. ytcast
works great with both these devices but I don't know
if it will work well on setups different than mine (it should, but I don't know
for sure). if it doesn't work on your setup please open an issue
describing your setup and attach a -verbose
log so we can investigate what's
wrong and hopefully fix it.
also Chromecast. I don't own a Chromecast and you'll probably need to use
the -pair
option (see workarounds) to make ytcast
work with Chromecast
because it doesn't use the DIAL protocol anymore, but switched to mDNS for
discovery.
BUGS
-
sometimes the playing queue gets "messed up" i.e. some videos are added between others, some videos don't get added at all or even an old queue might be "reused" so you could see videos from an old session after the ones you requested to play. unfortunately, using (or misusing) an undocumented api may lead to these kinds of problems and I haven't bothered too much trying to fix them.
-
the
-a
(add) option is slower because it does an api call for each video you want to add and adds a random "sleep delay" before each call. without this delay, the queue gets messed up more easily and videos get lost i.e. they don't get added to the queue. -
playing a video from a specific starting time (
t
parameter in urls) works only for the first video and only if you are not using the-a
(add) option. -
ytcast
doesn't appear inSettings > Linked devices
menu. it used to show up there and there was a button to "unlink all devices" which caused thescreenId
to change, but a YouTube update "broke" this feature.
workarounds
-
some devices don't support the DIAL protocol (notably Chromecast) so they can't be discovered by
ytcast
. the YouTube on TV app has a "link with code" functionality which can be used as workaround to pairytcast
with these devices. the pairing code can be found inSettings > Link with TV code
and then you can use the-pair
option to do the pairing:$ ytcast -pair 123456789101 8a59f138 unknown "YouTube on TV"
once paired you can cast videos in the usual way:
$ ytcast -d 8a59 https://www.youtube.com/watch?v=t0Q2otsqC4I
when using this method,
ytcast
and the target device do not need to be on the same network, but it adds many manual steps i.e. the YouTube on TV app must be already open becauseytcast
won't be able to start it nor to Wake-On-Lan the TV and it won't automatically "re-pair" when thescreenId
changes (I don't know how often that happens). -
playlist urls don't work with
ytcast
, I haven't found a reliable way to pass playlist ids to the api.youtube-dl
comes to the rescue (see also other tools) since it can extract all video urls of YouTube playlists:$ youtube-dl -j --flat-playlist https://www.youtube.com/playlist?list=PLrOv9FMX8xJHqMvSGB_9G9nZZ_4IgteYf | jq -r '.url' | ytcast -p
you can of course filter the pipeline as you like and this makes it so flexible that I actually don't feel the need for
ytcast
to support playlist urls: less is more! -
this might sound obvious, but if you are tired of typing the device name (even a substring of it) every time you want to cast something or if you have multiple devices with the same name, you can define shell aliases and benefit from shell tab-completion feature:
$ alias ytcbed="ytcast -d 'LG 32'" $ ytcbed https://www.youtube.com/watch?v=dQw4w9WgXcQ
(see your shell documentation to make aliases persistent, usually you have to add them in the shell's
rc
file).
THANKS
I would like to thank all the people whose work has helped me tremendously in
building ytcast
, especially the following projects/posts:
- https://0x41.cf/automation/2021/03/02/google-assistant-youtube-smart-tvs.html
- https://github.com/thedroidgeek/youtube-cast-automation-api
- https://github.com/mutantmonkey/youtube-remote
- https://bugs.xdavidhu.me/google/2021/04/05/i-built-a-tv-that-plays-all-of-your-private-youtube-videos
- https://github.com/aykevl/plaincast
- https://github.com/ur1katz/casttube
other tools
as I said earlier, my computing environment is very command-line centric and I'd like to showcase the other tools I use to enjoy a "no frills" YouTube experience from the terminal!
-
youtube-dl
(actuallyyt-dlp
these days) doesn't need introduction, it's an awesome tool and it's well integrated withmpv
so I can watch videos with my favorite player without having my laptop fan spin like an airplane engine thanks to thismpv
config:ytdl-format=bestvideo[height<=?1080][vcodec!=?vp9]+bestaudio/best
-
ytsearch
is my clone of the initial version ofytfzf
. it allows to search and select video urls from the command-line using the wonderfulfzf
(fun fact: it's implemented basically as a single big pipe ahah). you have already seen it in action inytcast
examples, but it works great withmpv
too:$ ytsearch matrix 4 | xargs mpv $ ytsearch 9 symphony | xargs mpv --no-video
-
ytxrss
allows to extract the rss feed url of a YouTube channel starting from a video or channel url. I use rss feeds (newsboat
) to keep up-to-date with things and I'm really glad YouTube still supports them for channel uploads. if I'm interested in a channel's future uploads, what I usually do is:$ ytxrss https://www.youtube.com/user/Computerphile >> ~/.newsboat/urls
see license file for copyright and license details.