On Sun, Mar 6, 2011 at 6:59 PM, Tom Hendrick <sdtom...@yahoo.com> wrote:
> 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 Tom, Look how piping to fifo files is handled in the gr-atsc. That might help get you going. Tom
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