Hi, I'm pretty new to pd but understand many of the concepts as I've been a written language programmer for quite some time.

I'm wondering if anyone knows a way to stream or grab video from other applications / programs running on a system for mixing with other videos in pd? I can mix videos, got those examples to work and have been playing with them.

However I want to mix in video from a program called IBNIZ (http://pelulamu.net/ibniz/), which is a live visual/audio coding lauguage. Any ideas?

I found this and it seems like it's up the right alley but not specifically to do with streaming / grabbing video from programs, right? http://puredata.info/community/conventions/convention09/zmolnig.pdf

Thanks for any help in this,
d3

Hi, in linux the only way to get or stream a video output from a program to another is by using videoloopback kernel module. In mac os X you can use syhon (if both program support it, and pd does)

cheers
husk

What about pipes? I'm a linux novice too, so now well up on this stuff. Asked a friend of mine a suggested I look into using pipes. Can pd take input from a pipe?

Do you have any more information about this videoloopback kernal module?

Thanks a lot husk

Hi,
here you can find debian package source of vloopback:
http://packages.debian.org/squeeze/vloopback-source

once you install it and you add module (trought terminal command "modprobe vloopback") a new /dev/video device will be created (something like /dev/video1).
Once you get it you need two programs: one to stream video output and another one to catch it.
Catch it is easy because is just a video4linux device (like a webcam). For example in pd/Gem you can use pix_video passing a message like:

| device /dev/video2(

In order to stream through vloopback instead the program you are using have to be "ready" for that.
In the case of puredata you will use pix_record object and a message like this:

| codec v4l2, file /dev/video1, record 1 (

where /dev/video depend on your vloopback device.

A practical example for that kind of use is creating video texture with puredata/gem and use lpmt (http://hv-a.com/lpmt/) for video mapping them.

I don't know if it is possible to stream video putput between programs using pipe. If you test it please report, I'm curious about that!

cheers
husk

Thanks for the ideas.

Tried them out and couldn't get every piece working together. I'm using Virtual Box to run linux so I've tried several different distros.

It seems vloopback 1.3 doesn't work with newer linux distros (I think it's the new kernal, 2.6, but I'm no expert) because vloopback.c includes /linux/videodev.h, which has been upgraded to videodev2.h Simply changing this doesn't work as the code also needs V4L1 to be supported, which it's not on new linux distros.

I was able to compile vloopback on Ubuntu 9.04 though and add the module. However I was unable to compile Ibniz (the program I want to generate the video signal) because I can't get SDL for it! Also couldn't find a PureData release to compile for it.

So it's a kind of catch 22. I was thinking though, even if I got it all working, Ibniz outputs video as such "Dump raw video to stdout and raw audio to stderr. 30 fps, non-realtime, yuv4mpeg2 and pcm_s16." So I wonder if puredata could even use it.

Any other ideas? Otherwise think I'm going to have to give up, maybe use Ibniz to create videos instead of doing live coding, or use a second laptop and send a video signal in if I purchased some extra hardware...

Thanks again
D3

@digithree said:

Hi, I'm pretty new to pd but understand many of the concepts as I've been a written language programmer for quite some time.

I'm wondering if anyone knows a way to stream or grab video from other applications / programs running on a system for mixing with other videos in pd? I can mix videos, got those examples to work and have been playing with them.

However I want to mix in video from a program called IBNIZ (http://pelulamu.net/ibniz/), which is a live visual/audio coding lauguage. Any ideas?

I found this and it seems like it's up the right alley but not specifically to do with streaming / grabbing video from programs, right? http://puredata.info/community/conventions/convention09/zmolnig.pdf

Thanks for any help in this,
d3

Hi d3,

It’s great to see you diving into video mixing with Pure Data! Grabbing or streaming video from another program like IBNIZ and mixing it in PD can indeed be tricky but is definitely possible with the right setup.

To grab video from external programs, you might consider the following approaches:

Screen Capture to Video Stream:
Use screen-capture software to stream the output from IBNIZ as a virtual webcam or a video feed. Tools like OBS Studio can help capture specific application windows and broadcast them as an RTMP stream or virtual camera. Then, you can bring that stream into PD using external libraries like GEM or Ofelia.

Direct Integration:
If IBNIZ has an option to output its visuals to a shared memory buffer or as a video stream, you could capture that directly in PD using plugins or extensions that handle video input.

External Tools:
Another possibility is using middleware like FFmpeg to convert the IBNIZ output into a format that PD can read. For example, you could use FFmpeg to stream the visuals to a local server and then access that stream from PD.

Feel free to share updates or questions—I'd love to hear how your project progresses!