| <title>Examples</title> | |
| <para>In this section we would like to present some examples for using the DVB API. | |
| </para> | |
| <para>Maintainer note: This section is out of date. Please refer to the sample programs packaged | |
| with the driver distribution from <ulink url="http://linuxtv.org/hg/dvb-apps" />. | |
| </para> | |
| <section id="tuning"> | |
| <title>Tuning</title> | |
| <para>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. | |
| </para> | |
| <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); | |
| } | |
| </programlisting> | |
| <para>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. | |
| </para> | |
| </section> | |
| <section id="the_dvr_device"> | |
| <title>The DVR device</title> | |
| <para>The following program code shows how to use the DVR device for recording. | |
| </para> | |
| <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/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; | |
| } | |
| </programlisting> | |
| </section> |