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| -rw-r--r-- | Documentation/DocBook/media/dvb/dvbproperty.xml | 40 |
1 files changed, 40 insertions, 0 deletions
diff --git a/Documentation/DocBook/media/dvb/dvbproperty.xml b/Documentation/DocBook/media/dvb/dvbproperty.xml index b91210d646cf..00ba1a9e314c 100644 --- a/Documentation/DocBook/media/dvb/dvbproperty.xml +++ b/Documentation/DocBook/media/dvb/dvbproperty.xml @@ -15,11 +15,13 @@ approach, in favor of a properties set approach.</para> <para>By using a properties set, it is now possible to extend and support any digital TV without needing to redesign the API</para> + <para>Example: with the properties based approach, in order to set the tuner to a DVB-C channel at 651 kHz, modulated with 256-QAM, FEC 3/4 and symbol rate of 5.217 Mbauds, those properties should be sent to <link linkend="FE_GET_PROPERTY"><constant>FE_SET_PROPERTY</constant></link> ioctl:</para> <itemizedlist> + <listitem>&DTV-DELIVERY-SYSTEM; = SYS_DVBC_ANNEX_A</listitem> <listitem>&DTV-FREQUENCY; = 651000000</listitem> <listitem>&DTV-MODULATION; = QAM_256</listitem> <listitem>&DTV-INVERSION; = INVERSION_AUTO</listitem> @@ -27,6 +29,44 @@ <listitem>&DTV-INNER-FEC; = FEC_3_4</listitem> <listitem>&DTV-TUNE;</listitem> </itemizedlist> + +<para>The code that would do the above is:</para> +<programlisting> +#include <stdio.h> +#include <fcntl.h> +#include <sys/ioctl.h> +#include <linux/dvb/frontend.h> + +static struct dtv_property props[] = { + { .cmd = DTV_DELIVERY_SYSTEM, .u.data = SYS_DVBC_ANNEX_A }, + { .cmd = DTV_FREQUENCY, .u.data = 651000000 }, + { .cmd = DTV_MODULATION, .u.data = QAM_256 }, + { .cmd = DTV_INVERSION, .u.data = INVERSION_AUTO }, + { .cmd = DTV_SYMBOL_RATE, .u.data = 5217000 }, + { .cmd = DTV_INNER_FEC, .u.data = FEC_3_4 }, + { .cmd = DTV_TUNE } +}; + +static struct dtv_properties dtv_prop = { + .num = 6, .props = props +}; + +int main(void) +{ + int fd = open("/dev/dvb/adapter0/frontend0", O_RDWR); + + if (!fd) { + perror ("open"); + return -1; + } + if (ioctl(fd, FE_SET_PROPERTY, &dtv_prop) == -1) { + perror("ioctl"); + return -1; + } + printf("Frontend set\n"); + return 0; +} +</programlisting> <para>NOTE: This section describes the DVB version 5 extension of the DVB-API, also called "S2API", as this API were added to provide support for DVB-S2. It was designed to be able to replace the old frontend API. Yet, the DISEQC and |