| .. -*- coding: utf-8; mode: rst -*- |
| |
| .. _dvb_examples: |
| |
| ******** |
| Examples |
| ******** |
| |
| In this section we would like to present some examples for using the Digital |
| TV API. |
| |
| .. note:: |
| |
| This section is out of date, and the code below won't even |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; |
| } |