The VideoLAN Forums

I am experimenting with VLC's support for Chromecast and Chromecast Audio devices using VLC 3.0.3 64 bit on Windows 10 1803.
My attempt to play a file to a Chromecast Audio via command line is not working.
The Chromecast Audio device in question has an IP address of 192.168.0.169, so the command line I issued was:
"C:\Program Files\VideoLAN\VLC\vlc.exe" "C:\Windows\media\Alarm01.wav" --sout="#chromecast{ip=192.168.0.169}"
This opens VLC, and I hear the connection tone on the speaker attached to the Chromecast Audio, however the file does not play.
If I remove the -sout option completely, then VLC opens and plays the file to my default audio device as expected.
Am I doing something incorrectly, or should I file a bug report?
Also, I was going to create another thread about a related issue, but I think I've started enough threads already, so I'll add this related question here.
Is there a way to specify a Chromecast Group instead of an individual Chromecast device?
I want to play to a group of speakers, not just one.
I can do this in the UI, which scans and detects the groups I've created and allows them to be selected as a Playback/Renderer (very nice), but I see no way to do this via command line.

Thanks so much for your work to date on Chromecast support!

--UPDATE--

It occurred to me that I should turn on logging, so I did, and this was the result (sorry for the length):

-- logger module started --
main debug: VLC media player - 3.0.3 Vetinari
main debug: Copyright © 1996-2018 the VideoLAN team
main debug: revision 3.0.3-1-0-gc2bb759264
main debug: configured with ../extras/package/win32/../../../configure '--enable-update-check' '--enable-lua' '--enable-faad' '--enable-flac' '--enable-theora' '--enable-twolame' '--enable-avcodec' '--enable-merge-ffmpeg' '--enable-dca' '--enable-mpc' '--enable-libass' '--enable-x264' '--enable-schroedinger' '--enable-realrtsp' '--enable-live555' '--enable-dvdread' '--enable-shout' '--enable-goom' '--enable-caca' '--enable-qt' '--enable-skins2' '--enable-sse' '--enable-mmx' '--enable-libcddb' '--enable-zvbi' '--disable-telx' '--enable-nls' '--host=x86_64-w64-mingw32' '--with-breakpad=https://win.crashes.videolan.org' 'host_alias=x86_64-w64-mingw32' 'PKG_CONFIG_LIBDIR=/home/jenkins/workspace/vlc-release/windows/vlc-release-win32-x64/contrib/x86_64-w64-mingw32/lib/pkgconfig'
main debug: using multimedia timers as clock source
main debug: min period: 1 ms, max period: 1000000 ms
main debug: searching plug-in modules
main debug: loading plugins cache file C:\Program Files\VideoLAN\VLC\plugins\plugins.dat
main debug: recursively browsing `C:\Program Files\VideoLAN\VLC\plugins'
main debug: plug-ins loaded: 490 modules
main debug: opening config file (C:\Users\Scott\AppData\Roaming\vlc\vlcrc)
main debug: looking for logger module matching "any": 2 candidates
file debug: opening logfile `D:\temp\vlc-log.txt'
main debug: using logger module "file"
main debug: translation test: code is "C"
main debug: looking for keystore module matching "memory": 3 candidates
main debug: using keystore module "memory"
main debug: CPU has capabilities MMX MMXEXT SSE SSE2 SSE3 SSSE3 SSE4.1 SSE4.2 FPU
main debug: Creating an input for 'Media Library'
main debug: Input is a meta file: disabling unneeded options
main debug: using timeshift granularity of 50 MiB
main debug: using timeshift path: C:\Users\Scott\AppData\Local\Temp
main debug: `file/directory:///C:/Users/Scott/AppData/Roaming/vlc/ml.xspf' gives access `file' demux `directory' path `/C:/Users/Scott/AppData/Roaming/vlc/ml.xspf'
main debug: creating demux: access='file' demux='directory' location='/C:/Users/Scott/AppData/Roaming/vlc/ml.xspf' file='C:\Users\Scott\AppData\Roaming\vlc\ml.xspf'
main debug: looking for access_demux module matching "file": 15 candidates
main debug: no access_demux modules matched
main debug: creating access: file:///C:/Users/Scott/AppData/Roaming/vlc/ml.xspf
main debug: (path: C:\Users\Scott\AppData\Roaming\vlc\ml.xspf)
main debug: looking for access module matching "file": 26 candidates
main debug: using access module "filesystem"
main debug: looking for stream_filter module matching "prefetch,cache_read": 24 candidates
cache_read debug: Using stream method for AStream*
cache_read debug: starting pre-buffering
cache_read debug: received first data after 0 ms
cache_read debug: pre-buffering done 304 bytes in 0s - 296875 KiB/s
main debug: using stream_filter module "cache_read"
main debug: looking for stream_filter module matching "any": 24 candidates
playlist debug: using XSPF playlist reader
main debug: using stream_filter module "playlist"
main debug: stream filter added to 0000000002b6b970
main debug: looking for stream_filter module matching "any": 24 candidates
main debug: no stream_filter modules matched
main debug: looking for stream_directory module matching "any": 1 candidates
main debug: no stream_directory modules matched
main debug: attachment of directory-extractor failed for file:///C:/Users/Scott/AppData/Roaming/vlc/ml.xspf
main debug: looking for stream_filter module matching "record": 24 candidates
main debug: using stream_filter module "record"
main debug: creating demux: access='file' demux='directory' location='/C:/Users/Scott/AppData/Roaming/vlc/ml.xspf' file='C:\Users\Scott\AppData\Roaming\vlc\ml.xspf'
main debug: looking for demux module matching "directory": 55 candidates
main debug: using demux module "directory"
main debug: looking for meta reader module matching "any": 2 candidates
lua debug: Trying Lua scripts in C:\Users\Scott\AppData\Roaming\vlc\lua\meta\reader
lua debug: Trying Lua scripts in C:\Program Files\VideoLAN\VLC\lua\meta\reader
lua debug: Trying Lua playlist script C:\Program Files\VideoLAN\VLC\lua\meta\reader\filename.luac
main debug: no meta reader modules matched
main debug: `file/directory:///C:/Users/Scott/AppData/Roaming/vlc/ml.xspf' successfully opened
main debug: looking for xml reader module matching "any": 1 candidates
main debug: using xml reader module "xml"
main debug: EOF reached
main debug: removing module "directory"
main debug: removing module "record"
main debug: removing module "playlist"
main debug: removing module "cache_read"
main debug: removing module "filesystem"
main debug: creating audio output
main debug: looking for audio output module matching "any": 6 candidates
mmdevice debug: using default device
mmdevice debug: display name changed: VLC media player (LibVLC 3.0.3)
mmdevice debug: version 2 session control unavailable
mmdevice debug: volume from -64.000000 dB to +0.000000 dB with 1.000000 dB increments
main debug: using audio output module "mmdevice"
main debug: keeping audio output
main debug: looking for interface module matching "hotkeys,none": 16 candidates
main debug: using interface module "hotkeys"
main debug: looking for interface module matching "globalhotkeys,none": 16 candidates
main debug: using interface module "win32"
main: Running vlc with the default interface. Use 'cvlc' to use vlc without interface.
main debug: looking for interface module matching "any": 16 candidates
main debug: looking for extension module matching "any": 1 candidates
lua debug: Opening Lua Extension module
lua debug: Trying Lua scripts in C:\Users\Scott\AppData\Roaming\vlc\lua\extensions
lua debug: Trying Lua scripts in C:\Program Files\VideoLAN\VLC\lua\extensions
lua debug: Trying Lua playlist script C:\Program Files\VideoLAN\VLC\lua\extensions\VLSub.luac
lua debug: Scanning Lua script C:\Program Files\VideoLAN\VLC\lua\extensions\VLSub.luac
lua debug: Script C:\Program Files\VideoLAN\VLC\lua\extensions\VLSub.luac has the following capability flags: 0x5
main debug: using extension module "lua"
main debug: looking for services probe module matching "any": 7 candidates
main debug: no services probe modules matched
qt debug: Sorting by column -1, order 0
qt debug: Sorting by column -1, order 0
main debug: using interface module "qt"
main debug: processing request item: null, node: Playlist, skip: 0
main debug: rebuilding array of current - root Playlist
main debug: rebuild done - 1 items, index -1
main debug: starting playback of new item
main debug: resyncing on Alarm01.wav
main debug: Alarm01.wav is at 0
main debug: creating new input thread
main debug: Creating an input for 'Alarm01.wav'
main debug: requesting art for new input thread
main debug: looking for meta fetcher module matching "any": 1 candidates
lua debug: Trying Lua scripts in C:\Users\Scott\AppData\Roaming\vlc\lua\meta\fetcher
lua debug: Trying Lua scripts in C:\Program Files\VideoLAN\VLC\lua\meta\fetcher
main debug: no meta fetcher modules matched
main debug: looking for art finder module matching "any": 2 candidates
main debug: using sout chain=`chromecast{ip=192.168.0.169}'
main debug: stream=`chromecast'
main debug: looking for sout stream module matching "chromecast": 23 candidates
lua debug: Trying Lua scripts in C:\Users\Scott\AppData\Roaming\vlc\lua\meta\art
lua debug: Trying Lua scripts in C:\Program Files\VideoLAN\VLC\lua\meta\art
lua debug: Trying Lua playlist script C:\Program Files\VideoLAN\VLC\lua\meta\art\00_musicbrainz.luac
lua debug: skipping script (unmatched scope) C:\Program Files\VideoLAN\VLC\lua\meta\art\00_musicbrainz.luac
lua debug: Trying Lua playlist script C:\Program Files\VideoLAN\VLC\lua\meta\art\01_googleimage.luac
main debug: set config option: sout-chromecast-ip to 192.168.0.169
main debug: net: listening to * port 8010
lua debug: skipping script (unmatched scope) C:\Program Files\VideoLAN\VLC\lua\meta\art\01_googleimage.luac
lua debug: Trying Lua playlist script C:\Program Files\VideoLAN\VLC\lua\meta\art\02_frenchtv.luac
main debug: looking for tls client module matching "any": 1 candidates
lua debug: skipping script (unmatched scope) C:\Program Files\VideoLAN\VLC\lua\meta\art\02_frenchtv.luac
lua debug: Trying Lua playlist script C:\Program Files\VideoLAN\VLC\lua\meta\art\03_lastfm.luac
lua debug: skipping script (unmatched scope) C:\Program Files\VideoLAN\VLC\lua\meta\art\03_lastfm.luac
main debug: no art finder modules matched
gnutls debug: using GnuTLS version 3.5.18
gnutls debug: loaded 68 trusted CAs from system
main debug: using tls client module "gnutls"
main debug: resolving 192.168.0.169 ...
gnutls debug: TLS handshake: Resource temporarily unavailable, try again.
gnutls debug: TLS handshake: Success.
gnutls debug: - safe renegotiation (RFC5746) enabled
gnutls debug: - extended master secret (RFC7627) enabled
gnutls debug: - false start (RFC7918) enabled
gnutls error: Certificate verification failure: The certificate is NOT trusted. The certificate issuer is unknown. The name in the certificate does not match the expected.
gnutls: Accepting self-signed/untrusted CA certificate.
main debug: stream=`http'
main debug: looking for sout stream module matching "http": 23 candidates
main debug: set config option: sout-standard-mux to avformat{mux=matroska,options={live=1}}
main debug: looking for sout access module matching "http": 10 candidates
main debug: net: listening to * port 8080
main debug: using sout access module "http"
main debug: looking for sout mux module matching "avformat": 11 candidates
avcodec debug: using ffmpeg Lavf58.3.100
avcodec debug: CPU flags: 0x000853db
main debug: set config option: sout-avformat-mux to matroska
main debug: set config option: sout-avformat-options to live=1
main debug: using sout mux module "avcodec"
stream_out_standard debug: using `http/avformat{mux=matroska,options={live=1}}://(null)'
main debug: using sout stream module "stream_out_standard"
main debug: destroying chain... (name=http)
main debug: removing module "stream_out_standard"
main debug: removing module "avcodec"
main debug: removing module "http"
main debug: HTTP host removed
http debug: Close
main debug: destroying chain done
main debug: using sout stream module "stream_out_chromecast"
main debug: using timeshift granularity of 50 MiB
main debug: using timeshift path: C:\Users\Scott\AppData\Local\Temp
main debug: `file:///C:/Windows/media/Alarm01.wav' gives access `file' demux `any' path `/C:/Windows/media/Alarm01.wav'
main debug: creating demux: access='file' demux='any' location='/C:/Windows/media/Alarm01.wav' file='C:\Windows\media\Alarm01.wav'
main debug: looking for access_demux module matching "file": 15 candidates
main debug: no access_demux modules matched
main debug: creating access: file:///C:/Windows/media/Alarm01.wav
main debug: (path: C:\Windows\media\Alarm01.wav)
main debug: looking for access module matching "file": 26 candidates
main debug: using access module "filesystem"
main debug: looking for stream_filter module matching "prefetch,cache_read": 24 candidates
cache_read debug: Using stream method for AStream*
cache_read debug: starting pre-buffering
cache_read debug: received first data after 0 ms
cache_read debug: pre-buffering done 1024 bytes in 0s - 1000000 KiB/s
main debug: using stream_filter module "cache_read"
main debug: looking for stream_filter module matching "any": 24 candidates
lua debug: Trying Lua scripts in C:\Users\Scott\AppData\Roaming\vlc\lua\playlist
lua debug: Trying Lua scripts in C:\Program Files\VideoLAN\VLC\lua\playlist
lua debug: Trying Lua playlist script C:\Program Files\VideoLAN\VLC\lua\playlist\anevia_streams.luac
lua debug: Trying Lua playlist script C:\Program Files\VideoLAN\VLC\lua\playlist\anevia_xml.luac
lua debug: Trying Lua playlist script C:\Program Files\VideoLAN\VLC\lua\playlist\appletrailers.luac
lua debug: Trying Lua playlist script C:\Program Files\VideoLAN\VLC\lua\playlist\bbc_co_uk.luac
lua debug: Trying Lua playlist script C:\Program Files\VideoLAN\VLC\lua\playlist\cue.luac
lua debug: Trying Lua playlist script C:\Program Files\VideoLAN\VLC\lua\playlist\dailymotion.luac
lua debug: Trying Lua playlist script C:\Program Files\VideoLAN\VLC\lua\playlist\jamendo.luac
lua debug: Trying Lua playlist script C:\Program Files\VideoLAN\VLC\lua\playlist\koreus.luac
lua debug: Trying Lua playlist script C:\Program Files\VideoLAN\VLC\lua\playlist\liveleak.luac
lua debug: Trying Lua playlist script C:\Program Files\VideoLAN\VLC\lua\playlist\newgrounds.luac
lua debug: Trying Lua playlist script C:\Program Files\VideoLAN\VLC\lua\playlist\rockbox_fm_presets.luac
lua debug: Trying Lua playlist script C:\Program Files\VideoLAN\VLC\lua\playlist\soundcloud.luac
lua debug: Trying Lua playlist script C:\Program Files\VideoLAN\VLC\lua\playlist\twitch.luac
stream_out_chromecast debug: Media receiver application was already running
lua debug: Trying Lua playlist script C:\Program Files\VideoLAN\VLC\lua\playlist\vimeo.luac
lua debug: Trying Lua playlist script C:\Program Files\VideoLAN\VLC\lua\playlist\vocaroo.luac
lua debug: Trying Lua playlist script C:\Program Files\VideoLAN\VLC\lua\playlist\youtube.luac
main debug: no stream_filter modules matched
main debug: looking for stream_directory module matching "any": 1 candidates
main debug: no stream_directory modules matched
main debug: attachment of directory-extractor failed for file:///C:/Windows/media/Alarm01.wav
main debug: looking for stream_filter module matching "record": 24 candidates
main debug: using stream_filter module "record"
main debug: creating demux: access='file' demux='any' location='/C:/Windows/media/Alarm01.wav' file='C:\Windows\media\Alarm01.wav'
main debug: looking for demux module matching "any": 55 candidates
wav debug: chunk: fcc=`fmt ` size=16
wav debug: format: 0x0001, fourcc: araw, channels: 2, freq: 22050 Hz, bitrate: 86Ko/s, blockalign: 4, bits/samples: 16, extra size: 0
wav debug: found Raw audio audio format
wav debug: chunk: fcc=`data` size=491472
main debug: selecting program id=0
main debug: using demux module "wav"
main debug: looking for a subtitle file in C:\Windows\media\
main debug: looking for packetizer module matching "any": 24 candidates
qt debug: IM: Setting an input
main debug: using packetizer module "copy"
main debug: starting in sync mode
main debug: looking for meta reader module matching "any": 2 candidates
lua debug: Trying Lua scripts in C:\Users\Scott\AppData\Roaming\vlc\lua\meta\reader
lua debug: Trying Lua scripts in C:\Program Files\VideoLAN\VLC\lua\meta\reader
lua debug: Trying Lua playlist script C:\Program Files\VideoLAN\VLC\lua\meta\reader\filename.luac
main debug: no meta reader modules matched
main debug: `file:///C:/Windows/media/Alarm01.wav' successfully opened
main debug: Buffering 0%
main debug: switching to async mode
main debug: Buffering 16%
main debug: Buffering 33%
main debug: adding a new sout input for `s16l` (sout_input: 00000000048b4d60)
main debug: Buffering 49%
main debug: Buffering 66%
main debug: Buffering 83%
main debug: Buffering 99%
main debug: Stream buffering done (349 ms in 0 ms)
main debug: Decoder wait done in 0 ms
stream_out_chromecast debug: can't remux audio track 0 codec s16l
stream_out_chromecast debug: Converting audio to mp3
stream_out_chromecast debug: Creating chain transcode{acodec=mp3 ,}:chromecast-proxy:std{mux=avformat{mux=matroska,options={live=1}},access=chromecast-http}
main debug: stream=`std'
main debug: looking for sout stream module matching "std": 23 candidates
main debug: set config option: sout-standard-mux to avformat{mux=matroska,options={live=1}}
main debug: set config option: sout-standard-access to chromecast-http
main debug: looking for sout access module matching "chromecast-http": 10 candidates
main debug: using sout access module "stream_out_chromecast"
main debug: looking for sout mux module matching "avformat": 11 candidates
avcodec debug: using ffmpeg Lavf58.3.100
avcodec debug: CPU flags: 0x000853db
main debug: set config option: sout-avformat-mux to matroska
main debug: set config option: sout-avformat-options to live=1
main debug: using sout mux module "avcodec"
stream_out_standard debug: using `chromecast-http/avformat{mux=matroska,options={live=1}}://(null)'
main debug: using sout stream module "stream_out_standard"
main debug: stream=`chromecast-proxy'
main debug: looking for sout stream module matching "chromecast-proxy": 23 candidates
main debug: using sout stream module "stream_out_chromecast"
main debug: stream=`transcode'
main debug: looking for sout stream module matching "transcode": 23 candidates
main debug: set config option: sout-transcode-acodec to mp3
stream_out_transcode debug: Checking codec mapping for mp3 got mp3
stream_out_transcode debug: codec audio=mp3 0Hz 0 channels 96Kb/s
main debug: using sout stream module "stream_out_transcode"
stream_out_transcode debug: creating audio transcoding from fcc=`s16l' to fcc=`mp3 '
main debug: looking for audio decoder module matching "any": 23 candidates
araw debug: samplerate:22050Hz channels:2 bits/sample:16
main debug: using audio decoder module "araw"
main debug: looking for encoder module matching "any": 23 candidates
avcodec debug: using ffmpeg Lavc58.6.103
avcodec debug: CPU flags: 0x000853db
avcodec debug: Trying to find more suitable sample format instead of s32p
avcodec debug: Using s16p as new sample format
avcodec debug: Trying to find packet sample format instead of planar s16p
avcodec debug: Ended up using s16p as sample format
avcodec debug: Creating channel order for reordering
avcodec debug: 0 1 mapped to 2
avcodec debug: 1 2 mapped to 4
avcodec debug: found encoder MPEG Audio layer 3
main debug: using encoder module "avcodec"
main debug: input 's16l' 22050 Hz Stereo frame=1 samples/4 bytes
main debug: conversion: 's16l'->'s16l' 22050 Hz->22050 Hz Stereo->Stereo
main debug: conversion pipeline complete
main debug: looking for audio resampler module matching "any": 3 candidates
main debug: using audio resampler module "ugly"
main debug: removing module "avcodec"
main debug: removing module "ugly"
main debug: looking for encoder module matching "any": 23 candidates
avcodec debug: using ffmpeg Lavc58.6.103
avcodec debug: CPU flags: 0x000853db
avcodec debug: Trying to find more suitable sample format instead of s32p
avcodec debug: Using s16p as new sample format
avcodec debug: Trying to find packet sample format instead of planar s16p
avcodec debug: Ended up using s16p as sample format
avcodec debug: Creating channel order for reordering
avcodec debug: 0 1 mapped to 2
avcodec debug: 1 2 mapped to 4
avcodec debug: found encoder MPEG Audio layer 3
main debug: using encoder module "avcodec"
main debug: input 's16l' 22050 Hz Stereo frame=1 samples/4 bytes
main debug: conversion: 's16l'->'s16l' 22050 Hz->22050 Hz Stereo->Stereo
main debug: conversion pipeline complete
main debug: looking for audio resampler module matching "any": 3 candidates
main debug: using audio resampler module "ugly"
main debug: adding a new input
avcodec debug: adding input
avcodec debug: writing header
stream_out_chromecast debug: Loading content
stream_out_chromecast debug: s_chromecast_url: http://192.168.0.141:8010/stream
main debug: EOF reached
main debug: waiting decoder fifos to empty
main debug: killing decoder fourcc `s16l'
main debug: removing module "copy"
main debug: removing a sout input (sout_input: 00000000048b4d60)
avcodec debug: Flushing..
avcodec warning: cannot encode one frame
avcodec debug: Flushing..
avcodec warning: cannot encode one frame
main debug: removing module "araw"
main debug: removing module "avcodec"
main debug: removing module "ugly"
avcodec debug: removing input
main warning: no more input streams for this mux
main debug: destroying chain... (name=transcode)
main debug: removing module "stream_out_transcode"
main debug: destroying chain done
main debug: destroying chain... (name=chromecast-proxy)
main debug: removing module "stream_out_chromecast"
main debug: destroying chain done
main debug: destroying chain... (name=std)
main debug: removing module "stream_out_standard"
main debug: removing module "avcodec"
main debug: removing module "stream_out_chromecast"
main debug: destroying chain done
main debug: removing module "wav"
main debug: removing module "record"
main debug: removing module "cache_read"
main debug: removing module "filesystem"
main debug: Program doesn't contain anymore ES
main debug: dead input
main debug: destroying useless sout
main debug: destroying chain... (name=chromecast)
main debug: removing module "stream_out_chromecast"
main debug: attempt to destroy nonexistent variable "sout-chromecast-sout-mux-caching"
main warning: force closing connections
main debug: HTTP host removed
main debug: destroying chain done
main debug: changing item without a request (current 0/1)
main debug: nothing to play
main: end of playlist, exiting
main debug: exiting
main debug: exiting
main debug: no exit handler
main debug: removing all interfaces
main debug: removing module "qt"
main debug: deactivating the playlist
main debug: removing module "mmdevice"
qt debug: IM: Deleting the input
qt debug: requesting exit...
qt debug: waiting for UI thread...
main debug: exiting
main debug: no exit handler
qt debug: QApp exec() finished
qt debug: Video is not needed anymore
qt debug: Playlist Destroyed
qt debug: Killing extension dialog provider
qt debug: ExtensionsDialogProvider is quitting...
main debug: removing module "lua"
main debug: removing module "win32"
main debug: removing module "hotkeys"
main debug: destroying
main debug: saving media library to file C:\Users\Scott\AppData\Roaming\vlc\ml.xspf.tmp5256
main debug: looking for playlist export module matching "export-xspf": 4 candidates
main debug: using playlist export module "export"
main debug: removing module "export"
main debug: deleting item `Media Library'
main debug: deleting item `Alarm01.wav'
main debug: deleting item `Playlist'
main debug: removing module "memory"
-- logger module stopped --

It's a bug. I have the same problem with chromecast audio.

It's a bug. I have the same problem with chromecast audio.

Thanks for sharing your experience.

I tried the VLC 4 BETA just to see if that worked but the same thing happened.

I also tried a much larger MP3 file and that didn't work either although it did play the first tenth of a second of it (estimating). It also plays the first 1/10 second of the alarm file now that I notice. I didn't notice before because the first 1/10 second of that sound file is not very loud.

So it looks like VLC STARTS to play the input and then gets unceremoniously cut off for some reason.

My hopes to use VLC to play sound bites to Chomecasted speakers via Windows Scheduled Tasks, anytime soon, are dimming.

SOLVED

I needed to add another parameter.

This is what worked:

"C:\Program Files\VideoLAN\VLC\vlc.exe" "C:\Windows\media\Alarm01.wav" --sout="#chromecast{ip=192.168.0.169}" --demux-filter=demux_chromecast

I was leaving off that last parameter. But who can really tell this, even after reading ALL the -H HELP there was, it still wasn't enough.

Now if I could only figure out how to play to a speaker group...

It worked! thank you!!!

Glad to have helped you Epsteyn.
VLC is a marvellous program, but unless you are a propellerhead, getting it to do the more arcane things it can do can be challenging.
I was googling for the better part of a day before I found someone talking about the --demux-filter option as it pertains to chromecasting.
No luck finding anything about casting to a speaker group via command line though.

I managed to cast to a group by casting to a different port on one of the devices, see my reply here
https://forum.videolan.org/viewtopic.php?t=143114

Thank you!
I will try this as I also was using that python program you mention.
I did manage to work around the problem of not being able to cast to the group by just spawning multiple cmd processes, each one casting to a separate chromecast.
But I would much rather just cast once to the group.