is it possible to route jackd through roc?

[jave]

I tried setting up a server with roc using pulseaudio. I can play sound using pulseaudio fine, and receive it on a client machine.

But is it possible to use jackd as well?

I tried this unsucessfully:

• starting jackd with qjackctl, with a dummy driver
• loading module-jack-sink into the pulseaudio
• starting hydrogen, routing through the jackd

this didnt give me any audio on the client though.

[gavv]

Hi,

I've no experience with JACK so far, and Roc currently has no direct JACK support. Adding it would be great, but for now nobody is working on it. Pull requests are welcome :)

Theoretically, if you want JACK on the receiver side, using module-jack-sink should work, except that it will cost you additional latency introduced by PulseAudio. You should do the following:

• load module-jack-sink
• ensure that it works; for example, you can run something like paplay -d <sink_name> test.wav, where sink_name is the name of the sink created by module-jack-sink (find it using pactl list sinks)
• load module-roc-sink-input
• connect Roc sink-input to JACK sink, like: pactl move-sink-input <sink_input_index> <sink_index>, where sink_input_index is the numeric index of the sink-input created by module-roc-sink-input (find it using pactl list sink-inputs) and sink_index is the numeric index of the sink created by module-jack-sink (find it using pactl list sinks)

The last can be also done via pavucontrol GUI.

If it does not work, it is probably a bug in Roc sink-input because theoretically JACK sink is a usual sink, Roc sink-input is a usual sink-input, and everything should just work.

You can also try to use roc-recv command-line tool instead of module-roc-sink-input PulseAudio module. You can run it like this:

roc-recv -vv -s rtp+rs8m::10001 -r rs8m::10002 -d pulseaudio -o <sink_name>

...where sink_name is the name of the sink created by module-jack-sink (find it using pactl list sinks).

[jave]

Thanks.

In my case I want jack on the sender, and roc on the receiver.

for instance like:

on the sender
hydrogen -> jack -> pulse -> roc

on the receiver
roc -> pulse -> speakers

I tried settnig something up on the server using module-jack-sink/source, but it didnt seem to work very well.

[gavv]

Ah, so you need jack + roc on the sender side.

I guess module-jack-sink will not help you because it allows PA to output to JACK, and you need the opposite.

Not sure about module-jack-source. I guess in this case, if you want to use module-roc-sink, you'll also need module-loopback that will transfer sound from module-jack-source to module-roc-sink because it's not possible to connect a source to a sink directly (see here: 1, 2). Or, alternatively, you can use roc-send tool instead of module-roc-sink. The tool can grab sound directly from PulseAudio source, which you can specify using -i option.

You can also try to do it without PulseAudio at all. You can try to create an ALSA loopback device (snd-aloop), configure JACK to use it as an output, and configure roc-send to use it as an input.

So the chain will be: hydrogen -> jack -> alsa loopback -> roc-send

Here you can find instructions how to create the loopback device and use it with roc-send tool. You can follow them and test that everything works without JACK. Then you'll have to register this loopback device as a JACK output (I guess using alsa_out tool) and connect hydrogen to this JACK output.

[gavv]

I've created #254.

[jave]

I finally got around to test your suggestion to use the alsa loopback device. I used qjacktctl to connect jackd with the alsa device. This worked well, thanks!

[ejeschke]

Stumbled across this wishing to do the same thing: stream audio out of JACK on server to simple network clients using pulse. FWIW, I managed to get something working somewhat reasonably (time will tell) with:

jack-stdout -e float <jack-port-out1> <jack-port-out2> \
| sox -t raw -r 44100 -e float -b 32 -c 2 - -t wav - \
| roc-send -vv -s rtp+rs8m:<recv-ip>:10001 -r rs8m:<recv-ip>:10002 -d wav -i -

I'm wondering if I can get rid of the middle sox conversion to WAV (looks like roc-send is linking to the sox library to do the input conversions anyway). Is there a "raw" stdin option to roc-send where I can specify the rate (e.g. 48000), bit depth (e.g. 16, 32), encoding (e.g. float, signed int), and number of channels? Seems like if you are using libsox to do the conversions it would already have the machinery in place to do this...

[gavv]

@ejeschke

Thanks for sharing!

Is there a "raw" stdin option to roc-send where I can specify the rate (e.g. 48000), bit depth (e.g. 16, 32), encoding (e.g. float, signed int), and number of channels?

There is an option to force specific sample rate (--rate). It's also possible to force specific file/sample format, e.g. s16 for signed 16-bit integers (--driver in master, --input-format in develop). In develop, you can also list supported formats using --list-supported options). These formats are actually the same as supported by sox (you can use them instead of raw in -t option).

However, so far there is no option to force specific number of channels. I think I'll add it in 0.3.