I'm a beginner still with linux/GNURadio so I couldn't really find any information that makes sense as to how gr-atsc handles the fifo piping.
I had seen an example online of someone that had done a transmission using the USRP and piping. They had piped the output of gstreamer using mkfifo like I had tried but I can't get any output on the USRP when I read from the file created by mkfifo.
--- On Mon, 3/7/11, Tom Rondeau <address@hidden> wrote:
From: Tom Rondeau <address@hidden>
Subject: Re: [Discuss-gnuradio] Piping to the USRP - mkfifo issue
To: "Tom Hendrick"
Date: Monday, March 7, 2011, 12:53 AM
On Sun, Mar 6, 2011 at 6:59 PM, Tom Hendrick <address@hidden>
I am using a web
camera to get an MPEG-4 rtsp stream that is set to a constant bitrate. I
have a script which pipes the rtsp stream to a code in C++. The C++
code modulates the signal and writes a .WAV file to the hard disk.
I have a python script which interfaces with GNURadio/USRP which I
created using GRC. This takes a file stored on the hard disk and
outputs the analog waveform on the output of the USRP and I run this in a
second terminal window.
Everything works on the transmitter side, except that I have a file that
is constantly increasing in size, and the USRP script starts from the
beginning of the file and plays for a certain time before stopping. If I
restart, it does it longer and longer each time as expected since the
file is increasing in size. I verified I have gotten an output on the
USRP using an oscilloscope and it looked fine.
I wanted to try and use piping with mkfifo.
When I erase the file that is written/read from with the couple of
scripts I have, I then use mkfifo temp.wav (where temp.wav is my .wav
Then I start my scripts that pipe the camera output to the temp.wav
file. In a second terminal window I then run my USRP script and it
seems to open the file but I don't get any output on the USRP.
Has anyone encountered this problem? I'm not sure what could be wrong, but
it works with a normal file as I described above. Any suggestions?
Thanks for your help!
Look how piping to fifo files is handled in the gr-atsc. That might help get you going.