Examples
********
-In this section we would like to present some examples for using the Digital
-TV API.
+In the past, we used to have a set of examples here. However, those
+examples got out of date and doesn't even compile nowadays.
-.. note::
+Also, nowadays, the best is to use the libdvbv5 DVB API nowadays,
+with is fully documented.
- This section is out of date, and the code below won't even
- compile. Please refer to the
- `libdvbv5 <https://linuxtv.org/docs/libdvbv5/index.html>`__ for
- updated/recommended examples.
-
-
-.. _tuning:
-
-Example: Tuning
-===============
-
-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.
-
-
-.. code-block:: c
-
- #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);
- }
-
-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.
-
-
-.. _the_dvr_device:
-
-Example: The DVR device
-========================
-
-The following program code shows how to use the DVR device for
-recording.
-
-
-.. code-block:: c
-
- #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/video.h>
- #include <sys/poll.h>
- #define DVR "/dev/dvb/adapter0/dvr1"
- #define AUDIO "/dev/dvb/adapter0/audio1"
- #define VIDEO "/dev/dvb/adapter0/video1"
-
- #define BUFFY (188*20)
- #define MAX_LENGTH (1024*1024*5) /* record 5MB */
-
-
- /* switch the demuxes to recording, assuming the transponder is tuned */
-
- /* demux1, demux2: file descriptor of video and audio filters */
- /* vpid, apid: PIDs of video and audio channels */
-
- int switch_to_record(int demux1, int demux2, uint16_t vpid, uint16_t apid)
- {
- struct dmx_pes_filter_params pesFilterParams;
-
- 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;
- }
- }
-
- pesFilterParams.pid = vpid;
- pesFilterParams.input = DMX_IN_FRONTEND;
- pesFilterParams.output = DMX_OUT_TS_TAP;
- pesFilterParams.pes_type = DMX_PES_VIDEO;
- pesFilterParams.flags = DMX_IMMEDIATE_START;
- if (ioctl(demux1, DMX_SET_PES_FILTER, &pesFilterParams) < 0){
- perror("DEMUX DEVICE");
- return -1;
- }
- pesFilterParams.pid = apid;
- pesFilterParams.input = DMX_IN_FRONTEND;
- pesFilterParams.output = DMX_OUT_TS_TAP;
- pesFilterParams.pes_type = DMX_PES_AUDIO;
- pesFilterParams.flags = DMX_IMMEDIATE_START;
- if (ioctl(demux2, DMX_SET_PES_FILTER, &pesFilterParams) < 0){
- perror("DEMUX DEVICE");
- return -1;
- }
- return 0;
- }
-
- /* start recording MAX_LENGTH , assuming the transponder is tuned */
-
- /* demux1, demux2: file descriptor of video and audio filters */
- /* vpid, apid: PIDs of video and audio channels */
- int record_dvr(int demux1, int demux2, uint16_t vpid, uint16_t apid)
- {
- int i;
- int len;
- int written;
- uint8_t buf[BUFFY];
- uint64_t length;
- struct pollfd pfd[1];
- int dvr, dvr_out;
-
- /* open dvr device */
- if ((dvr = open(DVR, O_RDONLY|O_NONBLOCK)) < 0){
- perror("DVR DEVICE");
- return -1;
- }
-
- /* switch video and audio demuxes to dvr */
- printf ("Switching dvr on\\n");
- i = switch_to_record(demux1, demux2, vpid, apid);
- printf("finished: ");
-
- printf("Recording %2.0f MB of test file in TS format\\n",
- MAX_LENGTH/(1024.0*1024.0));
- length = 0;
-
- /* open output file */
- if ((dvr_out = open(DVR_FILE,O_WRONLY|O_CREAT
- |O_TRUNC, S_IRUSR|S_IWUSR
- |S_IRGRP|S_IWGRP|S_IROTH|
- S_IWOTH)) < 0){
- perror("Can't open file for dvr test");
- return -1;
- }
-
- pfd[0].fd = dvr;
- pfd[0].events = POLLIN;
-
- /* poll for dvr data and write to file */
- while (length < MAX_LENGTH ) {
- if (poll(pfd,1,1)){
- if (pfd[0].revents & POLLIN){
- len = read(dvr, buf, BUFFY);
- if (len < 0){
- perror("recording");
- return -1;
- }
- if (len > 0){
- written = 0;
- while (written < len)
- written +=
- write (dvr_out,
- buf, len);
- length += len;
- printf("written %2.0f MB\\r",
- length/1024./1024.);
- }
- }
- }
- }
- return 0;
- }
+Please refer to the `libdvbv5 <https://linuxtv.org/docs/libdvbv5/index.html>`__
+for updated/recommended examples.
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