|
From: | Tom Hendrick |
Subject: | [Discuss-gnuradio] Piping to the USRP - mkfifo issue |
Date: | Sun, 6 Mar 2011 15:59:58 -0800 (PST) |
Hi 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 file). 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! -Tom |
[Prev in Thread] | Current Thread | [Next in Thread] |