<?xml version="1.0" encoding="ANSI_X3.4-1968" standalone="no"?>
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
<html xmlns="http://www.w3.org/1999/xhtml"><head><meta http-equiv="Content-Type" content="text/html; charset=ANSI_X3.4-1968" /><title>Chapter 16. Examples</title><meta name="generator" content="DocBook XSL Stylesheets V1.75.2" /><link rel="home" href="index.html" title="LINUX MEDIA INFRASTRUCTURE API" /><link rel="up" href="pt02.html" title="Part II. LINUX DVB API" /><link rel="prev" href="ch15s11.html" title="stop_filtering()" /><link rel="next" href="ch16s02.html" title="The DVR device" /></head><body><div class="navheader"><table width="100%" summary="Navigation header"><tr><th colspan="3" align="center">Chapter 16. Examples</th></tr><tr><td width="20%" align="left"><a accesskey="p" href="ch15s11.html">Prev</a> </td><th width="60%" align="center">Part II. LINUX DVB API</th><td width="20%" align="right"> <a accesskey="n" href="ch16s02.html">Next</a></td></tr></table><hr /></div><div class="chapter" title="Chapter 16. Examples"><div class="titlepage"><div><div><h2 class="title"><a id="dvb_examples"></a>Chapter 16. Examples</h2></div></div></div><div class="toc"><p><b>Table of Contents</b></p><dl><dt><span class="section"><a href="ch16.html#tuning">Tuning</a></span></dt><dt><span class="section"><a href="ch16s02.html">The DVR device</a></span></dt></dl></div><p>In this section we would like to present some examples for using the DVB API.
</p><p>Maintainer note: This section is out of date. Please refer to the sample programs packaged
with the driver distribution from <a class="ulink" href="http://linuxtv.org/hg/dvb-apps" target="_top">http://linuxtv.org/hg/dvb-apps</a>.
</p><div class="section" title="Tuning"><div class="titlepage"><div><div><h2 class="title" style="clear: both"><a id="tuning"></a>Tuning</h2></div></div></div><p>We will start with a generic tuning subroutine that uses the frontend and SEC, as well as
the demux devices. The example is given for QPSK tuners, but can easily be adjusted for
QAM.
</p><pre class="programlisting">
#include <sys/ioctl.h>
#include <stdio.h>
#include <stdint.h>
#include <sys/types.h>
#include <sys/stat.h>
#include <fcntl.h>
#include <time.h>
#include <unistd.h>
#include <linux/dvb/dmx.h>
#include <linux/dvb/frontend.h>
#include <linux/dvb/sec.h>
#include <sys/poll.h>
#define DMX "/dev/dvb/adapter0/demux1"
#define FRONT "/dev/dvb/adapter0/frontend1"
#define SEC "/dev/dvb/adapter0/sec1"
/⋆ routine for checking if we have a signal and other status information⋆/
int FEReadStatus(int fd, fe_status_t ⋆stat)
{
int ans;
if ( (ans = ioctl(fd,FE_READ_STATUS,stat) < 0)){
perror("FE READ STATUS: ");
return -1;
}
if (⋆stat & FE_HAS_POWER)
printf("FE HAS POWER\n");
if (⋆stat & FE_HAS_SIGNAL)
printf("FE HAS SIGNAL\n");
if (⋆stat & FE_SPECTRUM_INV)
printf("SPEKTRUM INV\n");
return 0;
}
/⋆ tune qpsk ⋆/
/⋆ freq: frequency of transponder ⋆/
/⋆ vpid, apid, tpid: PIDs of video, audio and teletext TS packets ⋆/
/⋆ diseqc: DiSEqC address of the used LNB ⋆/
/⋆ pol: Polarisation ⋆/
/⋆ srate: Symbol Rate ⋆/
/⋆ fec. FEC ⋆/
/⋆ lnb_lof1: local frequency of lower LNB band ⋆/
/⋆ lnb_lof2: local frequency of upper LNB band ⋆/
/⋆ lnb_slof: switch frequency of LNB ⋆/
int set_qpsk_channel(int freq, int vpid, int apid, int tpid,
int diseqc, int pol, int srate, int fec, int lnb_lof1,
int lnb_lof2, int lnb_slof)
{
struct secCommand scmd;
struct secCmdSequence scmds;
struct dmx_pes_filter_params pesFilterParams;
FrontendParameters frp;
struct pollfd pfd[1];
FrontendEvent event;
int demux1, demux2, demux3, front;
frequency = (uint32_t) freq;
symbolrate = (uint32_t) srate;
if((front = open(FRONT,O_RDWR)) < 0){
perror("FRONTEND DEVICE: ");
return -1;
}
if((sec = open(SEC,O_RDWR)) < 0){
perror("SEC DEVICE: ");
return -1;
}
if (demux1 < 0){
if ((demux1=open(DMX, O_RDWR|O_NONBLOCK))
< 0){
perror("DEMUX DEVICE: ");
return -1;
}
}
if (demux2 < 0){
if ((demux2=open(DMX, O_RDWR|O_NONBLOCK))
< 0){
perror("DEMUX DEVICE: ");
return -1;
}
}
if (demux3 < 0){
if ((demux3=open(DMX, O_RDWR|O_NONBLOCK))
< 0){
perror("DEMUX DEVICE: ");
return -1;
}
}
if (freq < lnb_slof) {
frp.Frequency = (freq - lnb_lof1);
scmds.continuousTone = SEC_TONE_OFF;
} else {
frp.Frequency = (freq - lnb_lof2);
scmds.continuousTone = SEC_TONE_ON;
}
frp.Inversion = INVERSION_AUTO;
if (pol) scmds.voltage = SEC_VOLTAGE_18;
else scmds.voltage = SEC_VOLTAGE_13;
scmd.type=0;
scmd.u.diseqc.addr=0x10;
scmd.u.diseqc.cmd=0x38;
scmd.u.diseqc.numParams=1;
scmd.u.diseqc.params[0] = 0xF0 | ((diseqc ⋆ 4) & 0x0F) |
(scmds.continuousTone == SEC_TONE_ON ? 1 : 0) |
(scmds.voltage==SEC_VOLTAGE_18 ? 2 : 0);
scmds.miniCommand=SEC_MINI_NONE;
scmds.numCommands=1;
scmds.commands=&scmd;
if (ioctl(sec, SEC_SEND_SEQUENCE, &scmds) < 0){
perror("SEC SEND: ");
return -1;
}
if (ioctl(sec, SEC_SEND_SEQUENCE, &scmds) < 0){
perror("SEC SEND: ");
return -1;
}
frp.u.qpsk.SymbolRate = srate;
frp.u.qpsk.FEC_inner = fec;
if (ioctl(front, FE_SET_FRONTEND, &frp) < 0){
perror("QPSK TUNE: ");
return -1;
}
pfd[0].fd = front;
pfd[0].events = POLLIN;
if (poll(pfd,1,3000)){
if (pfd[0].revents & POLLIN){
printf("Getting QPSK event\n");
if ( ioctl(front, FE_GET_EVENT, &event)
== -EOVERFLOW){
perror("qpsk get event");
return -1;
}
printf("Received ");
switch(event.type){
case FE_UNEXPECTED_EV:
printf("unexpected event\n");
return -1;
case FE_FAILURE_EV:
printf("failure event\n");
return -1;
case FE_COMPLETION_EV:
printf("completion event\n");
}
}
}
pesFilterParams.pid = vpid;
pesFilterParams.input = DMX_IN_FRONTEND;
pesFilterParams.output = DMX_OUT_DECODER;
pesFilterParams.pes_type = DMX_PES_VIDEO;
pesFilterParams.flags = DMX_IMMEDIATE_START;
if (ioctl(demux1, DMX_SET_PES_FILTER, &pesFilterParams) < 0){
perror("set_vpid");
return -1;
}
pesFilterParams.pid = apid;
pesFilterParams.input = DMX_IN_FRONTEND;
pesFilterParams.output = DMX_OUT_DECODER;
pesFilterParams.pes_type = DMX_PES_AUDIO;
pesFilterParams.flags = DMX_IMMEDIATE_START;
if (ioctl(demux2, DMX_SET_PES_FILTER, &pesFilterParams) < 0){
perror("set_apid");
return -1;
}
pesFilterParams.pid = tpid;
pesFilterParams.input = DMX_IN_FRONTEND;
pesFilterParams.output = DMX_OUT_DECODER;
pesFilterParams.pes_type = DMX_PES_TELETEXT;
pesFilterParams.flags = DMX_IMMEDIATE_START;
if (ioctl(demux3, DMX_SET_PES_FILTER, &pesFilterParams) < 0){
perror("set_tpid");
return -1;
}
return has_signal(fds);
}
</pre><p>The program assumes that you are using a universal LNB and a standard DiSEqC
switch with up to 4 addresses. Of course, you could build in some more checking if
tuning was successful and maybe try to repeat the tuning process. Depending on the
external hardware, i.e. LNB and DiSEqC switch, and weather conditions this may be
necessary.
</p></div></div><div class="navfooter"><hr /><table width="100%" summary="Navigation footer"><tr><td width="40%" align="left"><a accesskey="p" href="ch15s11.html">Prev</a> </td><td width="20%" align="center"><a accesskey="u" href="pt02.html">Up</a></td><td width="40%" align="right"> <a accesskey="n" href="ch16s02.html">Next</a></td></tr><tr><td width="40%" align="left" valign="top">stop_filtering() </td><td width="20%" align="center"><a accesskey="h" href="index.html">Home</a></td><td width="40%" align="right" valign="top"> The DVR device</td></tr></table></div></body></html>
