aler9 / gst-namedpipe

GStreamer element that allows to write/read data to/from named pipes

gst-namedpipe

GStreamer elements that allow to read/write incoming data to/from named pipes:

• namedpipesrc location=/path/to/namedpipe
• namedpipesink location=/path/to/namedpipe

These have a couple of advantages with respect to udpsrc and udpsink:

• named pipes are more efficient than UDP
• frame size is unlimited, while in UDP there's a limit of 65536 bytes

Frames are prefixed with their size, in order to allow readers to correctly split them.

Installation

Install build dependencies:

sudo apt install -y --no-install-recommends \
gcc \
meson \
libgstreamer-plugins-base1.0-dev

Compile and install:

meson --prefix=/usr build \
&& cd build \
&& ninja \
&& sudo ninja install

Usage

1. Create a named pipe

   mkfifo /tmp/testing
   

2. Write a reader, for instance this is a reader written in C

   #include <stdlib.h>
   #include <stdint.h>
   #include <fcntl.h>
   #include <unistd.h>
   
   int main() {
       int fd = open("/tmp/testing", O_RDWR);
       if (fd < 0) {
           printf("unable to open named pipe\n");
           return 1;
       }
   
       uint8_t buf[1024*1024];
   
       while (1) {
           uint32_t size = 0;
           size_t n = read(fd, &size, sizeof(uint32_t));
           if (n != sizeof(uint32_t)) {
               break;
           }
   
           n = read(fd, buf, size);
           if (n != size) {
               break;
           }
   
           printf("received %d\n", size);
       }
   
       return 0;
   }

   Compile and launch the reader

   gcc -o reader reader.c
   /reader &
   

3. Launch a pipeline

   gst-launch-1.0 \
   videotestsrc \
   ! video/x-raw,width=640,height=320,framerate=20/1 \
   ! namedpipesink location=/tmp/testing sync=1
   

   Data is now available to the reader.