Hello everyone!

I am very new to PD, but I know several people who use it for exactly what I am interested in.

I've been working on a FOSS project called LaserBoy for more than 21 years. It is a very comprehensive platform independent app with lots of associated technology for making full color animated 3D vector art that can be exported as multichannel wav files for directly controlling a laser projector, using a DC modified multichannel sound device.

Recently, I have developed a device I call the LaserBoy piDAC. It is a pi based network addressable DAC that becomes part of the laser projector, making it possible to connect many of them together on a private, wired gigabit network. Each one can be controlled independently and simultaneously.

The method I'm using to stream multichannel audio from a workstation to the piDAC is gstreamer. It works from Linux, Windows and presumably MacOS.

Without having to compile any code whatsoever, I am able to setup the piDAC to listen for UDP connections and, from the workstation end, I am able call a command that opens a local wav file and streams it to the piDAC address in near real-time -- all via gstreamer! (gst-launch-1.0)

So my question is, how do I make an object appear on my PD canvas that is some part of the gstreamer pipeline? Both ends would be ideal, as that would allow me to do in-stream audio processing on both ends.

I have looked at PdGst, but it seems like it is outdated and it does not compile on my current Ubuntu 24.10 workstation.

Ultimately, I would love to be able to place objects on the PD canvas that represent (multiple) piDAC sinks.

Thank you in advance.

James.

@James_LaserBoy You could ask at https://github.com/umlaeute/pdgst but although umlaeute is still very active a request from 2015 remains unanswered.
You could look at https://forum.pdpatchrepo.info/topic/14900/aoo-2-0-pre4-released which has objects for Pd available for all platforms, and for which you can host a server to which gstreamer can maybe connect.
David.

Thank you for your response. I will look at that. I think I might be able to do what I want the old fashioned way by creating a named pipe (fifo) and using PD to write to it while gstreamer is reading the other end.

Maybe someone has already written an OSC plugin for gstreamer, that might be a good thing for such a case.

Well, it doesn't work at all with a named pipe (fifo). But it kinda works with a real file. If I use readsf~ to open a file and writesf~ to save it, I can get that going in PD and in a shell, issue the gst-launch command that udp streams the file from the beginning. If I stop it in pd, it won't start again. I have to start all over. So that's not going to work.

@James_LaserBoy I wonder whether [udpsend~] and [udpreceive~] from the MrPeach library will work for this.
Channel count and buffer size would have to be set as I don't think the objects will negotiate the stream.
There are other objects, e,g, [ffplay~] .... there is a gstreamer ffmpeg library..... but they are mostly one way.

I wonder whether you can run pd extended..... the old 32-bit pd.... on your system and then use the old pdgst objects? Pd extended will run in 64-bit windows, but maybe not in Linux?
You might need a Ubuntu 32-bit virtual system installed to get Pd extended running.
You would then be able to use Pd extended just as an interface.... and then use [uspsend~] and [udpreceive~] to communicate with a 64-bit Pd vanilla open at the same time, unless you decide to do your audio processing entirely in Pd extended...... I cannot think of a good reason why you should not....
David.

Well I have ventured into the wild world of trying to write my own pd external.

It all looks good according to every bit of documentation I can find.

I'm using the pure-data/pd-lib-builder Makefile from github.

It builds ok, but when I try to make the object on the pd canvas, it fails.

/home/james/pd-externals/laserboy_pidac~.pd_linux: undefined symbol: gst_bin_add_many

It seems like the pd external isn't linking with the gstreamer libs.

I don't know how to address this.

Thanks.
James.