8e080c2e6c
The V4L and DVB API's are there for a long time. however, up to now, no efforts were done to merge them to kernel DocBook. This patch adds the current versions of the specs as an unique compendium. Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>
973 lines
26 KiB
XML
973 lines
26 KiB
XML
<title>DVB Demux Device</title>
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<para>The DVB demux device controls the filters of the DVB hardware/software. It can be
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accessed through <emphasis role="tt">/dev/adapter0/demux0</emphasis>. Data types and and ioctl definitions can be
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accessed by including <emphasis role="tt">linux/dvb/dmx.h</emphasis> in your application.
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</para>
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<section id="dmx_types">
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<title>Demux Data Types</title>
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<section id="dmx_output_t">
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<title>dmx_output_t</title>
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<programlisting>
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typedef enum
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{
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DMX_OUT_DECODER,
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DMX_OUT_TAP,
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DMX_OUT_TS_TAP
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} dmx_output_t;
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</programlisting>
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<para><emphasis role="tt">DMX_OUT_TAP</emphasis> delivers the stream output to the demux device on which the ioctl is
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called.
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</para>
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<para><emphasis role="tt">DMX_OUT_TS_TAP</emphasis> routes output to the logical DVR device <emphasis role="tt">/dev/dvb/adapter0/dvr0</emphasis>,
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which delivers a TS multiplexed from all filters for which <emphasis role="tt">DMX_OUT_TS_TAP</emphasis> was
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specified.
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</para>
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</section>
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<section id="dmx_input_t">
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<title>dmx_input_t</title>
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<programlisting>
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typedef enum
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{
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DMX_IN_FRONTEND,
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DMX_IN_DVR
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} dmx_input_t;
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</programlisting>
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</section>
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<section id="dmx_pes_type_t">
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<title>dmx_pes_type_t</title>
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<programlisting>
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typedef enum
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{
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DMX_PES_AUDIO,
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DMX_PES_VIDEO,
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DMX_PES_TELETEXT,
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DMX_PES_SUBTITLE,
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DMX_PES_PCR,
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DMX_PES_OTHER
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} dmx_pes_type_t;
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</programlisting>
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</section>
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<section id="dmx_event_t">
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<title>dmx_event_t</title>
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<programlisting>
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typedef enum
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{
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DMX_SCRAMBLING_EV,
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DMX_FRONTEND_EV
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} dmx_event_t;
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</programlisting>
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</section>
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<section id="dmx_scrambling_status_t">
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<title>dmx_scrambling_status_t</title>
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<programlisting>
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typedef enum
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{
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DMX_SCRAMBLING_OFF,
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DMX_SCRAMBLING_ON
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} dmx_scrambling_status_t;
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</programlisting>
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</section>
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<section id="dmx_filter">
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<title>struct dmx_filter</title>
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<programlisting>
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typedef struct dmx_filter
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{
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uint8_t filter[DMX_FILTER_SIZE];
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uint8_t mask[DMX_FILTER_SIZE];
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} dmx_filter_t;
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</programlisting>
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</section>
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<section id="dmx_sct_filter_params">
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<title>struct dmx_sct_filter_params</title>
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<programlisting>
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struct dmx_sct_filter_params
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{
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uint16_t pid;
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dmx_filter_t filter;
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uint32_t timeout;
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uint32_t flags;
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#define DMX_CHECK_CRC 1
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#define DMX_ONESHOT 2
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#define DMX_IMMEDIATE_START 4
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};
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</programlisting>
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</section>
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<section id="dmx_pes_filter_params">
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<title>struct dmx_pes_filter_params</title>
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<programlisting>
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struct dmx_pes_filter_params
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{
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uint16_t pid;
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dmx_input_t input;
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dmx_output_t output;
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dmx_pes_type_t pes_type;
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uint32_t flags;
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};
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</programlisting>
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</section>
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<section id="dmx_event">
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<title>struct dmx_event</title>
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<programlisting>
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struct dmx_event
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{
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dmx_event_t event;
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time_t timeStamp;
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union
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{
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dmx_scrambling_status_t scrambling;
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} u;
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};
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</programlisting>
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</section>
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<section id="dmx_stc">
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<title>struct dmx_stc</title>
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<programlisting>
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struct dmx_stc {
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unsigned int num; /⋆ input : which STC? 0..N ⋆/
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unsigned int base; /⋆ output: divisor for stc to get 90 kHz clock ⋆/
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uint64_t stc; /⋆ output: stc in 'base'⋆90 kHz units ⋆/
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};
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</programlisting>
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</section>
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</section>
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<section id="dmx_fcalls">
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<title>Demux Function Calls</title>
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<section id="dmx_fopen">
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<title>open()</title>
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<para>DESCRIPTION
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</para>
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<informaltable><tgroup cols="1"><tbody><row><entry
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align="char">
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<para>This system call, used with a device name of /dev/dvb/adapter0/demux0,
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allocates a new filter and returns a handle which can be used for subsequent
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control of that filter. This call has to be made for each filter to be used, i.e. every
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returned file descriptor is a reference to a single filter. /dev/dvb/adapter0/dvr0
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is a logical device to be used for retrieving Transport Streams for digital
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video recording. When reading from this device a transport stream containing
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the packets from all PES filters set in the corresponding demux device
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(/dev/dvb/adapter0/demux0) having the output set to DMX_OUT_TS_TAP. A
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recorded Transport Stream is replayed by writing to this device. </para>
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<para>The significance of blocking or non-blocking mode is described in the
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documentation for functions where there is a difference. It does not affect the
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semantics of the open() call itself. A device opened in blocking mode can later
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be put into non-blocking mode (and vice versa) using the F_SETFL command
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of the fcntl system call.</para>
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</entry>
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</row></tbody></tgroup></informaltable>
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<para>SYNOPSIS
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</para>
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<informaltable><tgroup cols="1"><tbody><row><entry
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align="char">
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<para>int open(const char ⋆deviceName, int flags);</para>
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</entry>
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</row></tbody></tgroup></informaltable>
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<para>PARAMETERS
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</para>
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<informaltable><tgroup cols="2"><tbody><row><entry
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align="char">
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<para>const char
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*deviceName</para>
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</entry><entry
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align="char">
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<para>Name of demux device.</para>
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</entry>
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</row><row><entry
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align="char">
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<para>int flags</para>
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</entry><entry
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align="char">
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<para>A bit-wise OR of the following flags:</para>
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</entry>
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</row><row><entry
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align="char">
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</entry><entry
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align="char">
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<para>O_RDWR read/write access</para>
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</entry>
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</row><row><entry
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align="char">
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</entry><entry
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align="char">
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<para>O_NONBLOCK open in non-blocking mode</para>
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</entry>
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</row><row><entry
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align="char">
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</entry><entry
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align="char">
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<para>(blocking mode is the default)</para>
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</entry>
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</row></tbody></tgroup></informaltable>
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<para>ERRORS
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</para>
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<informaltable><tgroup cols="2"><tbody><row><entry
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align="char">
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<para>ENODEV</para>
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</entry><entry
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align="char">
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<para>Device driver not loaded/available.</para>
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</entry>
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</row><row><entry
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align="char">
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<para>EINVAL</para>
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</entry><entry
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align="char">
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<para>Invalid argument.</para>
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</entry>
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</row><row><entry
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align="char">
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<para>EMFILE</para>
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</entry><entry
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align="char">
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<para>“Too many open files”, i.e. no more filters available.</para>
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</entry>
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</row><row><entry
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align="char">
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<para>ENOMEM</para>
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</entry><entry
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align="char">
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<para>The driver failed to allocate enough memory.</para>
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</entry>
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</row></tbody></tgroup></informaltable>
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</section>
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<section id="dmx_fclose">
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<title>close()</title>
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<para>DESCRIPTION
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</para>
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<informaltable><tgroup cols="1"><tbody><row><entry
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align="char">
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<para>This system call deactivates and deallocates a filter that was previously
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allocated via the open() call.</para>
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</entry>
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</row></tbody></tgroup></informaltable>
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<para>SYNOPSIS
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</para>
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<informaltable><tgroup cols="1"><tbody><row><entry
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align="char">
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<para>int close(int fd);</para>
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</entry>
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</row></tbody></tgroup></informaltable>
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<para>PARAMETERS
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</para>
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<informaltable><tgroup cols="2"><tbody><row><entry
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align="char">
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<para>int fd</para>
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</entry><entry
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align="char">
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<para>File descriptor returned by a previous call to open().</para>
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</entry>
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</row></tbody></tgroup></informaltable>
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<para>ERRORS
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</para>
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<informaltable><tgroup cols="2"><tbody><row><entry
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align="char">
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<para>EBADF</para>
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</entry><entry
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align="char">
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<para>fd is not a valid open file descriptor.</para>
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</entry>
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</row></tbody></tgroup></informaltable>
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</section>
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<section id="dmx_fread">
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<title>read()</title>
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<para>DESCRIPTION
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</para>
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<informaltable><tgroup cols="1"><tbody><row><entry
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align="char">
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<para>This system call returns filtered data, which might be section or PES data. The
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filtered data is transferred from the driver’s internal circular buffer to buf. The
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maximum amount of data to be transferred is implied by count.</para>
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</entry>
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</row><row><entry
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align="char">
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<para>When returning section data the driver always tries to return a complete single
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section (even though buf would provide buffer space for more data). If the size
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of the buffer is smaller than the section as much as possible will be returned,
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and the remaining data will be provided in subsequent calls.</para>
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</entry>
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</row><row><entry
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align="char">
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<para>The size of the internal buffer is 2 * 4096 bytes (the size of two maximum
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sized sections) by default. The size of this buffer may be changed by using the
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DMX_SET_BUFFER_SIZE function. If the buffer is not large enough, or if
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the read operations are not performed fast enough, this may result in a buffer
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overflow error. In this case EOVERFLOW will be returned, and the circular
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buffer will be emptied. This call is blocking if there is no data to return, i.e. the
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process will be put to sleep waiting for data, unless the O_NONBLOCK flag
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is specified.</para>
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</entry>
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</row><row><entry
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align="char">
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<para>Note that in order to be able to read, the filtering process has to be started
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by defining either a section or a PES filter by means of the ioctl functions,
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and then starting the filtering process via the DMX_START ioctl function
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or by setting the DMX_IMMEDIATE_START flag. If the reading is done
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from a logical DVR demux device, the data will constitute a Transport Stream
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including the packets from all PES filters in the corresponding demux device
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/dev/dvb/adapter0/demux0 having the output set to DMX_OUT_TS_TAP.</para>
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</entry>
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</row></tbody></tgroup></informaltable>
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<para>SYNOPSIS
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</para>
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<informaltable><tgroup cols="1"><tbody><row><entry
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align="char">
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<para>size_t read(int fd, void ⋆buf, size_t count);</para>
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</entry>
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</row></tbody></tgroup></informaltable>
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<para>PARAMETERS
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</para>
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<informaltable><tgroup cols="2"><tbody><row><entry
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align="char">
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<para>int fd</para>
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</entry><entry
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align="char">
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<para>File descriptor returned by a previous call to open().</para>
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</entry>
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</row><row><entry
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align="char">
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<para>void *buf</para>
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</entry><entry
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align="char">
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<para>Pointer to the buffer to be used for returned filtered data.</para>
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</entry>
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</row><row><entry
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align="char">
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<para>size_t count</para>
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</entry><entry
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align="char">
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<para>Size of buf.</para>
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</entry>
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</row></tbody></tgroup></informaltable>
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<para>ERRORS
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</para>
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<informaltable><tgroup cols="2"><tbody><row><entry
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align="char">
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<para>EWOULDBLOCK</para>
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</entry><entry
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align="char">
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<para>No data to return and O_NONBLOCK was specified.</para>
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</entry>
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</row><row><entry
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align="char">
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<para>EBADF</para>
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</entry><entry
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align="char">
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<para>fd is not a valid open file descriptor.</para>
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</entry>
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</row><row><entry
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align="char">
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<para>ECRC</para>
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</entry><entry
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align="char">
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<para>Last section had a CRC error - no data returned. The
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buffer is flushed.</para>
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</entry>
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</row><row><entry
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align="char">
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<para>EOVERFLOW</para>
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</entry><entry
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align="char">
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</entry>
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</row><row><entry
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align="char">
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</entry><entry
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align="char">
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<para>The filtered data was not read from the buffer in due
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time, resulting in non-read data being lost. The buffer is
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flushed.</para>
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</entry>
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</row><row><entry
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align="char">
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<para>ETIMEDOUT</para>
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</entry><entry
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align="char">
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<para>The section was not loaded within the stated timeout
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period. See ioctl DMX_SET_FILTER for how to set a
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timeout.</para>
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</entry>
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</row><row><entry
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align="char">
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<para>EFAULT</para>
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</entry><entry
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align="char">
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<para>The driver failed to write to the callers buffer due to an
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invalid *buf pointer.</para>
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</entry>
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</row></tbody></tgroup></informaltable>
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</section>
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<section id="dmx_fwrite">
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<title>write()</title>
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<para>DESCRIPTION
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</para>
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<informaltable><tgroup cols="1"><tbody><row><entry
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align="char">
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<para>This system call is only provided by the logical device /dev/dvb/adapter0/dvr0,
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associated with the physical demux device that provides the actual DVR
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functionality. It is used for replay of a digitally recorded Transport Stream.
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Matching filters have to be defined in the corresponding physical demux
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device, /dev/dvb/adapter0/demux0. The amount of data to be transferred is
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implied by count.</para>
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</entry>
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</row></tbody></tgroup></informaltable>
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<para>SYNOPSIS
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</para>
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<informaltable><tgroup cols="1"><tbody><row><entry
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align="char">
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<para>ssize_t write(int fd, const void ⋆buf, size_t
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count);</para>
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</entry>
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</row></tbody></tgroup></informaltable>
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<para>PARAMETERS
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</para>
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<informaltable><tgroup cols="2"><tbody><row><entry
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align="char">
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<para>int fd</para>
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</entry><entry
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align="char">
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<para>File descriptor returned by a previous call to open().</para>
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</entry>
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</row><row><entry
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align="char">
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<para>void *buf</para>
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</entry><entry
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align="char">
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<para>Pointer to the buffer containing the Transport Stream.</para>
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</entry>
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</row><row><entry
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align="char">
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<para>size_t count</para>
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</entry><entry
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align="char">
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<para>Size of buf.</para>
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</entry>
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</row></tbody></tgroup></informaltable>
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<para>ERRORS
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</para>
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<informaltable><tgroup cols="2"><tbody><row><entry
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align="char">
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<para>EWOULDBLOCK</para>
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</entry><entry
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align="char">
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<para>No data was written. This
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might happen if O_NONBLOCK was specified and there
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is no more buffer space available (if O_NONBLOCK is
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not specified the function will block until buffer space is
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available).</para>
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</entry>
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</row><row><entry
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align="char">
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<para>EBUSY</para>
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</entry><entry
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align="char">
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<para>This error code indicates that there are conflicting
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requests. The corresponding demux device is setup to
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receive data from the front- end. Make sure that these
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filters are stopped and that the filters with input set to
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DMX_IN_DVR are started.</para>
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</entry>
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</row><row><entry
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align="char">
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<para>EBADF</para>
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</entry><entry
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align="char">
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<para>fd is not a valid open file descriptor.</para>
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</entry>
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</row></tbody></tgroup></informaltable>
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</section>
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|
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<section id="dmx_start">
|
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<title>DMX_START</title>
|
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<para>DESCRIPTION
|
|
</para>
|
|
<informaltable><tgroup cols="1"><tbody><row><entry
|
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align="char">
|
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<para>This ioctl call is used to start the actual filtering operation defined via the ioctl
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calls DMX_SET_FILTER or DMX_SET_PES_FILTER.</para>
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</entry>
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</row></tbody></tgroup></informaltable>
|
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<para>SYNOPSIS
|
|
</para>
|
|
<informaltable><tgroup cols="1"><tbody><row><entry
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align="char">
|
|
<para>int ioctl( int fd, int request = DMX_START);</para>
|
|
</entry>
|
|
</row></tbody></tgroup></informaltable>
|
|
<para>PARAMETERS
|
|
</para>
|
|
<informaltable><tgroup cols="2"><tbody><row><entry
|
|
align="char">
|
|
<para>int fd</para>
|
|
</entry><entry
|
|
align="char">
|
|
<para>File descriptor returned by a previous call to open().</para>
|
|
</entry>
|
|
</row><row><entry
|
|
align="char">
|
|
<para>int request</para>
|
|
</entry><entry
|
|
align="char">
|
|
<para>Equals DMX_START for this command.</para>
|
|
</entry>
|
|
</row></tbody></tgroup></informaltable>
|
|
<para>ERRORS
|
|
</para>
|
|
<informaltable><tgroup cols="2"><tbody><row><entry
|
|
align="char">
|
|
<para>EBADF</para>
|
|
</entry><entry
|
|
align="char">
|
|
<para>fd is not a valid file descriptor.</para>
|
|
</entry>
|
|
</row><row><entry
|
|
align="char">
|
|
<para>EINVAL</para>
|
|
</entry><entry
|
|
align="char">
|
|
<para>Invalid argument, i.e. no filtering parameters provided via
|
|
the DMX_SET_FILTER or DMX_SET_PES_FILTER
|
|
functions.</para>
|
|
</entry>
|
|
</row><row><entry
|
|
align="char">
|
|
<para>EBUSY</para>
|
|
</entry><entry
|
|
align="char">
|
|
<para>This error code indicates that there are conflicting
|
|
requests. There are active filters filtering data from
|
|
another input source. Make sure that these filters are
|
|
stopped before starting this filter.</para>
|
|
</entry>
|
|
</row></tbody></tgroup></informaltable>
|
|
</section>
|
|
|
|
<section id="dmx_stop">
|
|
<title>DMX_STOP</title>
|
|
<para>DESCRIPTION
|
|
</para>
|
|
<informaltable><tgroup cols="1"><tbody><row><entry
|
|
align="char">
|
|
<para>This ioctl call is used to stop the actual filtering operation defined via the
|
|
ioctl calls DMX_SET_FILTER or DMX_SET_PES_FILTER and started via
|
|
the DMX_START command.</para>
|
|
</entry>
|
|
</row></tbody></tgroup></informaltable>
|
|
<para>SYNOPSIS
|
|
</para>
|
|
<informaltable><tgroup cols="1"><tbody><row><entry
|
|
align="char">
|
|
<para>int ioctl( int fd, int request = DMX_STOP);</para>
|
|
</entry>
|
|
</row></tbody></tgroup></informaltable>
|
|
<para>PARAMETERS
|
|
</para>
|
|
<informaltable><tgroup cols="2"><tbody><row><entry
|
|
align="char">
|
|
<para>int fd</para>
|
|
</entry><entry
|
|
align="char">
|
|
<para>File descriptor returned by a previous call to open().</para>
|
|
</entry>
|
|
</row><row><entry
|
|
align="char">
|
|
<para>int request</para>
|
|
</entry><entry
|
|
align="char">
|
|
<para>Equals DMX_STOP for this command.</para>
|
|
</entry>
|
|
</row></tbody></tgroup></informaltable>
|
|
<para>ERRORS
|
|
</para>
|
|
<informaltable><tgroup cols="2"><tbody><row><entry
|
|
align="char">
|
|
<para>EBADF</para>
|
|
</entry><entry
|
|
align="char">
|
|
<para>fd is not a valid file descriptor.</para>
|
|
</entry>
|
|
</row></tbody></tgroup></informaltable>
|
|
</section>
|
|
|
|
<section id="dmx_set_filter">
|
|
<title>DMX_SET_FILTER</title>
|
|
<para>DESCRIPTION
|
|
</para>
|
|
<informaltable><tgroup cols="1"><tbody><row><entry
|
|
align="char">
|
|
<para>This ioctl call sets up a filter according to the filter and mask parameters
|
|
provided. A timeout may be defined stating number of seconds to wait for a
|
|
section to be loaded. A value of 0 means that no timeout should be applied.
|
|
Finally there is a flag field where it is possible to state whether a section should
|
|
be CRC-checked, whether the filter should be a ”one-shot” filter, i.e. if the
|
|
filtering operation should be stopped after the first section is received, and
|
|
whether the filtering operation should be started immediately (without waiting
|
|
for a DMX_START ioctl call). If a filter was previously set-up, this filter will
|
|
be canceled, and the receive buffer will be flushed.</para>
|
|
</entry>
|
|
</row></tbody></tgroup></informaltable>
|
|
<para>SYNOPSIS
|
|
</para>
|
|
<informaltable><tgroup cols="1"><tbody><row><entry
|
|
align="char">
|
|
<para>int ioctl( int fd, int request = DMX_SET_FILTER,
|
|
struct dmx_sct_filter_params ⋆params);</para>
|
|
</entry>
|
|
</row></tbody></tgroup></informaltable>
|
|
<para>PARAMETERS
|
|
</para>
|
|
<informaltable><tgroup cols="2"><tbody><row><entry
|
|
align="char">
|
|
<para>int fd</para>
|
|
</entry><entry
|
|
align="char">
|
|
<para>File descriptor returned by a previous call to open().</para>
|
|
</entry>
|
|
</row><row><entry
|
|
align="char">
|
|
<para>int request</para>
|
|
</entry><entry
|
|
align="char">
|
|
<para>Equals DMX_SET_FILTER for this command.</para>
|
|
</entry>
|
|
</row><row><entry
|
|
align="char">
|
|
<para>struct
|
|
dmx_sct_filter_params
|
|
*params</para>
|
|
</entry><entry
|
|
align="char">
|
|
<para>Pointer to structure containing filter parameters.</para>
|
|
</entry>
|
|
</row></tbody></tgroup></informaltable>
|
|
<para>ERRORS
|
|
</para>
|
|
<informaltable><tgroup cols="2"><tbody><row><entry
|
|
align="char">
|
|
<para>EBADF</para>
|
|
</entry><entry
|
|
align="char">
|
|
<para>fd is not a valid file descriptor.</para>
|
|
</entry>
|
|
</row><row><entry
|
|
align="char">
|
|
<para>EINVAL</para>
|
|
</entry><entry
|
|
align="char">
|
|
<para>Invalid argument.</para>
|
|
</entry>
|
|
</row></tbody></tgroup></informaltable>
|
|
</section>
|
|
|
|
<section id="dmx_set_pes_filter">
|
|
<title>DMX_SET_PES_FILTER</title>
|
|
<para>DESCRIPTION
|
|
</para>
|
|
<informaltable><tgroup cols="1"><tbody><row><entry
|
|
align="char">
|
|
<para>This ioctl call sets up a PES filter according to the parameters provided. By a
|
|
PES filter is meant a filter that is based just on the packet identifier (PID), i.e.
|
|
no PES header or payload filtering capability is supported.</para>
|
|
</entry>
|
|
</row><row><entry
|
|
align="char">
|
|
<para>The transport stream destination for the filtered output may be set. Also the
|
|
PES type may be stated in order to be able to e.g. direct a video stream directly
|
|
to the video decoder. Finally there is a flag field where it is possible to state
|
|
whether the filtering operation should be started immediately (without waiting
|
|
for a DMX_START ioctl call). If a filter was previously set-up, this filter will
|
|
be cancelled, and the receive buffer will be flushed.</para>
|
|
</entry>
|
|
</row></tbody></tgroup></informaltable>
|
|
<para>SYNOPSIS
|
|
</para>
|
|
<informaltable><tgroup cols="1"><tbody><row><entry
|
|
align="char">
|
|
<para>int ioctl( int fd, int request = DMX_SET_PES_FILTER,
|
|
struct dmx_pes_filter_params ⋆params);</para>
|
|
</entry>
|
|
</row></tbody></tgroup></informaltable>
|
|
<para>PARAMETERS
|
|
</para>
|
|
<informaltable><tgroup cols="2"><tbody><row><entry
|
|
align="char">
|
|
<para>int fd</para>
|
|
</entry><entry
|
|
align="char">
|
|
<para>File descriptor returned by a previous call to open().</para>
|
|
</entry>
|
|
</row><row><entry
|
|
align="char">
|
|
<para>int request</para>
|
|
</entry><entry
|
|
align="char">
|
|
<para>Equals DMX_SET_PES_FILTER for this command.</para>
|
|
</entry>
|
|
</row><row><entry
|
|
align="char">
|
|
<para>struct
|
|
dmx_pes_filter_params
|
|
*params</para>
|
|
</entry><entry
|
|
align="char">
|
|
<para>Pointer to structure containing filter parameters.</para>
|
|
</entry>
|
|
</row></tbody></tgroup></informaltable>
|
|
<para>ERRORS
|
|
</para>
|
|
<informaltable><tgroup cols="2"><tbody><row><entry
|
|
align="char">
|
|
<para>EBADF</para>
|
|
</entry><entry
|
|
align="char">
|
|
<para>fd is not a valid file descriptor.</para>
|
|
</entry>
|
|
</row><row><entry
|
|
align="char">
|
|
<para>EINVAL</para>
|
|
</entry><entry
|
|
align="char">
|
|
<para>Invalid argument.</para>
|
|
</entry>
|
|
</row><row><entry
|
|
align="char">
|
|
<para>EBUSY</para>
|
|
</entry><entry
|
|
align="char">
|
|
<para>This error code indicates that there are conflicting
|
|
requests. There are active filters filtering data from
|
|
another input source. Make sure that these filters are
|
|
stopped before starting this filter.</para>
|
|
</entry>
|
|
</row></tbody></tgroup></informaltable>
|
|
</section>
|
|
|
|
<section id="dms_set_buffer_size">
|
|
<title>DMX_SET_BUFFER_SIZE</title>
|
|
<para>DESCRIPTION
|
|
</para>
|
|
<informaltable><tgroup cols="1"><tbody><row><entry
|
|
align="char">
|
|
<para>This ioctl call is used to set the size of the circular buffer used for filtered data.
|
|
The default size is two maximum sized sections, i.e. if this function is not called
|
|
a buffer size of 2 * 4096 bytes will be used.</para>
|
|
</entry>
|
|
</row></tbody></tgroup></informaltable>
|
|
<para>SYNOPSIS
|
|
</para>
|
|
<informaltable><tgroup cols="1"><tbody><row><entry
|
|
align="char">
|
|
<para>int ioctl( int fd, int request =
|
|
DMX_SET_BUFFER_SIZE, unsigned long size);</para>
|
|
</entry>
|
|
</row></tbody></tgroup></informaltable>
|
|
<para>PARAMETERS
|
|
</para>
|
|
<informaltable><tgroup cols="2"><tbody><row><entry
|
|
align="char">
|
|
<para>int fd</para>
|
|
</entry><entry
|
|
align="char">
|
|
<para>File descriptor returned by a previous call to open().</para>
|
|
</entry>
|
|
</row><row><entry
|
|
align="char">
|
|
<para>int request</para>
|
|
</entry><entry
|
|
align="char">
|
|
<para>Equals DMX_SET_BUFFER_SIZE for this command.</para>
|
|
</entry>
|
|
</row><row><entry
|
|
align="char">
|
|
<para>unsigned long size</para>
|
|
</entry><entry
|
|
align="char">
|
|
<para>Size of circular buffer.</para>
|
|
</entry>
|
|
</row></tbody></tgroup></informaltable>
|
|
<para>ERRORS
|
|
</para>
|
|
<informaltable><tgroup cols="2"><tbody><row><entry
|
|
align="char">
|
|
<para>EBADF</para>
|
|
</entry><entry
|
|
align="char">
|
|
<para>fd is not a valid file descriptor.</para>
|
|
</entry>
|
|
</row><row><entry
|
|
align="char">
|
|
<para>ENOMEM</para>
|
|
</entry><entry
|
|
align="char">
|
|
<para>The driver was not able to allocate a buffer of the
|
|
requested size.</para>
|
|
</entry>
|
|
</row></tbody></tgroup></informaltable>
|
|
</section>
|
|
|
|
<section id="dmx_get_event">
|
|
<title>DMX_GET_EVENT</title>
|
|
<para>DESCRIPTION
|
|
</para>
|
|
<informaltable><tgroup cols="1"><tbody><row><entry
|
|
align="char">
|
|
<para>This ioctl call returns an event if available. If an event is not available,
|
|
the behavior depends on whether the device is in blocking or non-blocking
|
|
mode. In the latter case, the call fails immediately with errno set to
|
|
EWOULDBLOCK. In the former case, the call blocks until an event becomes
|
|
available.</para>
|
|
</entry>
|
|
</row><row><entry
|
|
align="char">
|
|
<para>The standard Linux poll() and/or select() system calls can be used with the
|
|
device file descriptor to watch for new events. For select(), the file descriptor
|
|
should be included in the exceptfds argument, and for poll(), POLLPRI should
|
|
be specified as the wake-up condition. Only the latest event for each filter is
|
|
saved.</para>
|
|
</entry>
|
|
</row></tbody></tgroup></informaltable>
|
|
<para>SYNOPSIS
|
|
</para>
|
|
<informaltable><tgroup cols="1"><tbody><row><entry
|
|
align="char">
|
|
<para>int ioctl( int fd, int request = DMX_GET_EVENT,
|
|
struct dmx_event ⋆ev);</para>
|
|
</entry>
|
|
</row></tbody></tgroup></informaltable>
|
|
<para>PARAMETERS
|
|
</para>
|
|
<informaltable><tgroup cols="2"><tbody><row><entry
|
|
align="char">
|
|
<para>int fd</para>
|
|
</entry><entry
|
|
align="char">
|
|
<para>File descriptor returned by a previous call to open().</para>
|
|
</entry>
|
|
</row><row><entry
|
|
align="char">
|
|
<para>int request</para>
|
|
</entry><entry
|
|
align="char">
|
|
<para>Equals DMX_GET_EVENT for this command.</para>
|
|
</entry>
|
|
</row><row><entry
|
|
align="char">
|
|
<para>struct dmx_event *ev</para>
|
|
</entry><entry
|
|
align="char">
|
|
<para>Pointer to the location where the event is to be stored.</para>
|
|
</entry>
|
|
</row></tbody></tgroup></informaltable>
|
|
<para>ERRORS
|
|
</para>
|
|
<informaltable><tgroup cols="2"><tbody><row><entry
|
|
align="char">
|
|
<para>EBADF</para>
|
|
</entry><entry
|
|
align="char">
|
|
<para>fd is not a valid file descriptor.</para>
|
|
</entry>
|
|
</row><row><entry
|
|
align="char">
|
|
<para>EFAULT</para>
|
|
</entry><entry
|
|
align="char">
|
|
<para>ev points to an invalid address.</para>
|
|
</entry>
|
|
</row><row><entry
|
|
align="char">
|
|
<para>EWOULDBLOCK</para>
|
|
</entry><entry
|
|
align="char">
|
|
<para>There is no event pending, and the device is in
|
|
non-blocking mode.</para>
|
|
</entry>
|
|
</row></tbody></tgroup></informaltable>
|
|
</section>
|
|
|
|
<section id="dmx_get_stc">
|
|
<title>DMX_GET_STC</title>
|
|
<para>DESCRIPTION
|
|
</para>
|
|
<informaltable><tgroup cols="1"><tbody><row><entry
|
|
align="char">
|
|
<para>This ioctl call returns the current value of the system time counter (which is driven
|
|
by a PES filter of type DMX_PES_PCR). Some hardware supports more than one
|
|
STC, so you must specify which one by setting the num field of stc before the ioctl
|
|
(range 0...n). The result is returned in form of a ratio with a 64 bit numerator
|
|
and a 32 bit denominator, so the real 90kHz STC value is stc->stc /
|
|
stc->base
|
|
.</para>
|
|
</entry>
|
|
</row></tbody></tgroup></informaltable>
|
|
<para>SYNOPSIS
|
|
</para>
|
|
<informaltable><tgroup cols="1"><tbody><row><entry
|
|
align="char">
|
|
<para>int ioctl( int fd, int request = DMX_GET_STC, struct
|
|
dmx_stc ⋆stc);</para>
|
|
</entry>
|
|
</row></tbody></tgroup></informaltable>
|
|
<para>PARAMETERS
|
|
</para>
|
|
<informaltable><tgroup cols="2"><tbody><row><entry
|
|
align="char">
|
|
<para>int fd</para>
|
|
</entry><entry
|
|
align="char">
|
|
<para>File descriptor returned by a previous call to open().</para>
|
|
</entry>
|
|
</row><row><entry
|
|
align="char">
|
|
<para>int request</para>
|
|
</entry><entry
|
|
align="char">
|
|
<para>Equals DMX_GET_STC for this command.</para>
|
|
</entry>
|
|
</row><row><entry
|
|
align="char">
|
|
<para>struct dmx_stc *stc</para>
|
|
</entry><entry
|
|
align="char">
|
|
<para>Pointer to the location where the stc is to be stored.</para>
|
|
</entry>
|
|
</row></tbody></tgroup></informaltable>
|
|
<para>ERRORS
|
|
</para>
|
|
<informaltable><tgroup cols="2"><tbody><row><entry
|
|
align="char">
|
|
<para>EBADF</para>
|
|
</entry><entry
|
|
align="char">
|
|
<para>fd is not a valid file descriptor.</para>
|
|
</entry>
|
|
</row><row><entry
|
|
align="char">
|
|
<para>EFAULT</para>
|
|
</entry><entry
|
|
align="char">
|
|
<para>stc points to an invalid address.</para>
|
|
</entry>
|
|
</row><row><entry
|
|
align="char">
|
|
<para>EINVAL</para>
|
|
</entry><entry
|
|
align="char">
|
|
<para>Invalid stc number.</para>
|
|
</entry>
|
|
</row></tbody></tgroup></informaltable>
|
|
</section></section>
|