Looking for a way to forward the audio of a PC to a tablet. So far I could
not find a direct way having ALSA make it (I refuse to install Pulse Audio
or any other sound server). Or is there a way?

Then I got the idea to stream it. I already have icecast2 along with
liquidsoap installed to have a "web radio" working. Can liquidsoap (or
better, icecast itself) stream audio from the PC to the web (well to the
tablet then)? My working config for liquidsoap currently looks like

liquidsoap 'output.icecast(%vorbis, host = "localhost", port = 10000,
password = "my_password", mount = "/stream", playlist.safe("playlist.pls"))'

I suppose I must replace

playlist.safe("playlist.pls")

with something. But what?
--
Andreas

https://news-commentaries.blogspot.com/

Andreas Kohlbach <...@spamfence.net> [AK]:
AK> Looking for a way to forward the audio of a PC to a tablet.

Is it gonna be one-way only (i.e. no microphone input sent back
to the PC) ?

If the answer is yes and you have console access to the tablet, then
you might achieve what you 're after by setting a fifo as alsa's sink
device and running a couple of netcat/nc/socat processes (one on
each device).

Andreas Kohlbach <ank@spamfence.net> wrote:
> Looking for a way to forward the audio of a PC to a tablet. So far I could
> not find a direct way having ALSA make it (I refuse to install Pulse Audio
> or any other sound server). Or is there a way?
>
> Then I got the idea to stream it. I already have icecast2 along with
> liquidsoap installed to have a "web radio" working. Can liquidsoap (or
> better, icecast itself) stream audio from the PC to the web (well to the
> tablet then)? My working config for liquidsoap currently looks like

About streaming audio I know nothing, but it sounds like this will
involve recording the output from the sound card which I have
attempted before. On that aspect, you need to check whether your
sound card has a loop-back device available. If not, then you'll
need to physically insert an audio cable from the audio output
socket to the line-in socket, and record from that, using a
splitter cable/block if you still want that audio output to go
to some speakers as well.

--
__ __
#_ < |\| |< _#

On 2021-06-05, Computer Nerd Kev <not@telling.you.invalid> wrote:
> Andreas Kohlbach <ank@spamfence.net> wrote:
>> Looking for a way to forward the audio of a PC to a tablet. So far I could
>> not find a direct way having ALSA make it (I refuse to install Pulse Audio
>> or any other sound server). Or is there a way?
>>
>> Then I got the idea to stream it. I already have icecast2 along with
>> liquidsoap installed to have a "web radio" working. Can liquidsoap (or
>> better, icecast itself) stream audio from the PC to the web (well to the
>> tablet then)? My working config for liquidsoap currently looks like
>
> About streaming audio I know nothing, but it sounds like this will
> involve recording the output from the sound card which I have
> attempted before. On that aspect, you need to check whether your
> sound card has a loop-back device available. If not, then you'll
> need to physically insert an audio cable from the audio output
> socket to the line-in socket, and record from that, using a
> splitter cable/block if you still want that audio output to go
> to some speakers as well.

In case it might be applicable, there is a way to tell plain ALSA
to write the output of a soundcard to a file.

Put something similar to this in your ~/.asoundrc file, adjusting
for whatever sound devices your machine has:

vvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvv cut here vvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvv
pcm.Intel { type hw; card Intel; }
ctl.Intel { type hw; card Intel; }
pcm.NVidia { type hw; card NVidia; }
ctl.NVidia { type hw; card NVidia; }

pcm.rate48000Hz {
type rate
slave {
pcm writeFile # Direct to the plugin which will write to a file
format S16_LE
# channels 2
rate 48000
}
#route_policy copy
}

pcm.writeFile {
type file
slave {
pcm "Intel" # Now write to the actual sound card
}
file "aplay-D_card0-t_raw-f_S16_LE-r48000-c_2.raw"
format "raw"
}

pcm.!default {
type plug
slave.pcm "rate48000Hz"
} ctl.!default ctl.Intel
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ cut here ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^

Play something to test it out.

Remove the file and run the real program. Some programs
(Musescore, for example) require a specific rate of 48000.

Convert it to WAV:

sox -r 48k -e signed -b 16 -c 2 \
aplay-D_card0-t_raw-f_S16_LE-r48000-c_2.raw \
-r 44100 something.wav

Crop it as needed.

Optional: Convert it to MP3:

ffmpeg -i something.wav something.mp3

HTH

--
Robert Riches
spamtrap42@jacob21819.net
(Yes, that is one of my email addresses.)

On Sat, 5 Jun 2021 00:27:29 +0000 (UTC), Computer Nerd Kev wrote:
>
> Andreas Kohlbach <ank@spamfence.net> wrote:
>> Looking for a way to forward the audio of a PC to a tablet. So far I could
>> not find a direct way having ALSA make it (I refuse to install Pulse Audio
>> or any other sound server). Or is there a way?
>>
>> Then I got the idea to stream it. I already have icecast2 along with
>> liquidsoap installed to have a "web radio" working. Can liquidsoap (or
>> better, icecast itself) stream audio from the PC to the web (well to the
>> tablet then)? My working config for liquidsoap currently looks like
>
> About streaming audio I know nothing, but it sounds like this will
> involve recording the output from the sound card which I have
> attempted before. On that aspect, you need to check whether your
> sound card has a loop-back device available. If not, then you'll
> need to physically insert an audio cable from the audio output
> socket to the line-in socket, and record from that, using a
> splitter cable/block if you still want that audio output to go
> to some speakers as well.

Having dead speakers in the notebook and no cables I hoped to forward the
audio of it to the tablet (until I get new speakers). And because
streaming of prerecorded files works, I hoped I could direct the audio
output to liquidsoap.

Saving a file is not what I want, unless liquidsoap can use it as input
to feed icecast with it in real time (or close to).
--
Andreas

Andreas Kohlbach <ank@spamfence.net> wrote:
>
> Having dead speakers in the notebook and no cables I hoped to forward the
> audio of it to the tablet (until I get new speakers). And because
> streaming of prerecorded files works, I hoped I could direct the audio
> output to liquidsoap.
>
> Saving a file is not what I want, unless liquidsoap can use it as input
> to feed icecast with it in real time (or close to).

A web search brought up this result very quickly:

https://tldp.org/HOWTO/MP3-HOWTO-11.html
Under heading "LiveIce":
"LiveIce can work in 2 modes, it can pass a playlist to Icecast or
can pass live audio from the soundcard."

http://liveice.sourceforge.net/

--
__ __
#_ < |\| |< _#

On Sun, 6 Jun 2021 01:57:57 +0000 (UTC), Computer Nerd Kev wrote:
>
> Andreas Kohlbach <ank@spamfence.net> wrote:
>>
>> Having dead speakers in the notebook and no cables I hoped to forward the
>> audio of it to the tablet (until I get new speakers). And because
>> streaming of prerecorded files works, I hoped I could direct the audio
>> output to liquidsoap.
>>
>> Saving a file is not what I want, unless liquidsoap can use it as input
>> to feed icecast with it in real time (or close to).
>
> A web search brought up this result very quickly:
>
> https://tldp.org/HOWTO/MP3-HOWTO-11.html
> Under heading "LiveIce":
> "LiveIce can work in 2 modes, it can pass a playlist to Icecast or
> can pass live audio from the soundcard."
>
> http://liveice.sourceforge.net/

Thanks, will have a look at this.

But I assumed liquidsoap can do this too. And since already working I
just needed the right term to search for (which was "cast") and for

| Input from the soundcard
| | If you’re lucky and have a working ALSA support, try one of these… but
| beware that ALSA may not work out of the box.
| | liquidsoap 'output.alsa(input.alsa())'

No luck yet, getting

| 2021/06/06 06:14:17 [alsa_out(default):2] Underrun!

but I suppose I have to put that into the call I usually use...
--
Andreas

PGP fingerprint 952B0A9F12C2FD6C9F7E68DAA9C2EA89D1A370E0