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+<title>DVB Demux Device</title>
+
+<para>The DVB demux device controls the filters of the DVB hardware/software. It can be
+accessed through <emphasis role="tt">/dev/adapter0/demux0</emphasis>. Data types and and ioctl definitions can be
+accessed by including <emphasis role="tt">linux/dvb/dmx.h</emphasis> in your application.
+</para>
+<section id="dmx_types">
+<title>Demux Data Types</title>
+
+<section id="dmx_output_t">
+<title>dmx_output_t</title>
+ <programlisting>
+ typedef enum
+ {
+ DMX_OUT_DECODER,
+ DMX_OUT_TAP,
+ DMX_OUT_TS_TAP
+ } dmx_output_t;
+</programlisting>
+<para><emphasis role="tt">DMX_OUT_TAP</emphasis> delivers the stream output to the demux device on which the ioctl is
+called.
+</para>
+<para><emphasis role="tt">DMX_OUT_TS_TAP</emphasis> routes output to the logical DVR device <emphasis role="tt">/dev/dvb/adapter0/dvr0</emphasis>,
+which delivers a TS multiplexed from all filters for which <emphasis role="tt">DMX_OUT_TS_TAP</emphasis> was
+specified.
+</para>
+</section>
+
+<section id="dmx_input_t">
+<title>dmx_input_t</title>
+ <programlisting>
+ typedef enum
+ {
+ DMX_IN_FRONTEND,
+ DMX_IN_DVR
+ } dmx_input_t;
+</programlisting>
+</section>
+
+<section id="dmx_pes_type_t">
+<title>dmx_pes_type_t</title>
+ <programlisting>
+ typedef enum
+ {
+ DMX_PES_AUDIO,
+ DMX_PES_VIDEO,
+ DMX_PES_TELETEXT,
+ DMX_PES_SUBTITLE,
+ DMX_PES_PCR,
+ DMX_PES_OTHER
+ } dmx_pes_type_t;
+</programlisting>
+</section>
+
+<section id="dmx_event_t">
+<title>dmx_event_t</title>
+ <programlisting>
+ typedef enum
+ {
+ DMX_SCRAMBLING_EV,
+ DMX_FRONTEND_EV
+ } dmx_event_t;
+</programlisting>
+</section>
+
+<section id="dmx_scrambling_status_t">
+<title>dmx_scrambling_status_t</title>
+ <programlisting>
+ typedef enum
+ {
+ DMX_SCRAMBLING_OFF,
+ DMX_SCRAMBLING_ON
+ } dmx_scrambling_status_t;
+</programlisting>
+</section>
+
+<section id="dmx_filter">
+<title>struct dmx_filter</title>
+ <programlisting>
+ typedef struct dmx_filter
+ {
+ uint8_t filter[DMX_FILTER_SIZE];
+ uint8_t mask[DMX_FILTER_SIZE];
+ } dmx_filter_t;
+</programlisting>
+</section>
+
+<section id="dmx_sct_filter_params">
+<title>struct dmx_sct_filter_params</title>
+ <programlisting>
+ struct dmx_sct_filter_params
+ {
+ uint16_t pid;
+ dmx_filter_t filter;
+ uint32_t timeout;
+ uint32_t flags;
+ #define DMX_CHECK_CRC 1
+ #define DMX_ONESHOT 2
+ #define DMX_IMMEDIATE_START 4
+ };
+</programlisting>
+</section>
+
+<section id="dmx_pes_filter_params">
+<title>struct dmx_pes_filter_params</title>
+ <programlisting>
+ struct dmx_pes_filter_params
+ {
+ uint16_t pid;
+ dmx_input_t input;
+ dmx_output_t output;
+ dmx_pes_type_t pes_type;
+ uint32_t flags;
+ };
+</programlisting>
+</section>
+
+<section id="dmx_event">
+<title>struct dmx_event</title>
+ <programlisting>
+ struct dmx_event
+ {
+ dmx_event_t event;
+ time_t timeStamp;
+ union
+ {
+ dmx_scrambling_status_t scrambling;
+ } u;
+ };
+</programlisting>
+</section>
+
+<section id="dmx_stc">
+<title>struct dmx_stc</title>
+ <programlisting>
+ struct dmx_stc {
+ unsigned int num; /&#x22C6; input : which STC? 0..N &#x22C6;/
+ unsigned int base; /&#x22C6; output: divisor for stc to get 90 kHz clock &#x22C6;/
+ uint64_t stc; /&#x22C6; output: stc in 'base'&#x22C6;90 kHz units &#x22C6;/
+ };
+</programlisting>
+ </section>
+
+</section>
+
+<section id="dmx_fcalls">
+<title>Demux Function Calls</title>
+
+<section id="dmx_fopen">
+<title>open()</title>
+<para>DESCRIPTION
+</para>
+<informaltable><tgroup cols="1"><tbody><row><entry
+ align="char">
+<para>This system call, used with a device name of /dev/dvb/adapter0/demux0,
+ allocates a new filter and returns a handle which can be used for subsequent
+ control of that filter. This call has to be made for each filter to be used, i.e. every
+ returned file descriptor is a reference to a single filter. /dev/dvb/adapter0/dvr0
+ is a logical device to be used for retrieving Transport Streams for digital
+ video recording. When reading from this device a transport stream containing
+ the packets from all PES filters set in the corresponding demux device
+ (/dev/dvb/adapter0/demux0) having the output set to DMX_OUT_TS_TAP. A
+ recorded Transport Stream is replayed by writing to this device. </para>
+<para>The significance of blocking or non-blocking mode is described in the
+ documentation for functions where there is a difference. It does not affect the
+ semantics of the open() call itself. A device opened in blocking mode can later
+ be put into non-blocking mode (and vice versa) using the F_SETFL command
+ of the fcntl system call.</para>
+</entry>
+ </row></tbody></tgroup></informaltable>
+<para>SYNOPSIS
+</para>
+<informaltable><tgroup cols="1"><tbody><row><entry
+ align="char">
+<para>int open(const char &#x22C6;deviceName, int flags);</para>
+</entry>
+ </row></tbody></tgroup></informaltable>
+<para>PARAMETERS
+</para>
+<informaltable><tgroup cols="2"><tbody><row><entry
+ align="char">
+<para>const char
+ *deviceName</para>
+</entry><entry
+ align="char">
+<para>Name of demux device.</para>
+</entry>
+ </row><row><entry
+ align="char">
+<para>int flags</para>
+</entry><entry
+ align="char">
+<para>A bit-wise OR of the following flags:</para>
+</entry>
+ </row><row><entry
+ align="char">
+</entry><entry
+ align="char">
+<para>O_RDWR read/write access</para>
+</entry>
+ </row><row><entry
+ align="char">
+</entry><entry
+ align="char">
+<para>O_NONBLOCK open in non-blocking mode</para>
+</entry>
+ </row><row><entry
+ align="char">
+</entry><entry
+ align="char">
+<para>(blocking mode is the default)</para>
+</entry>
+ </row></tbody></tgroup></informaltable>
+<para>ERRORS
+</para>
+<informaltable><tgroup cols="2"><tbody><row><entry
+ align="char">
+<para>ENODEV</para>
+</entry><entry
+ align="char">
+<para>Device driver not loaded/available.</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>EMFILE</para>
+</entry><entry
+ align="char">
+<para>&#8220;Too many open files&#8221;, i.e. no more filters available.</para>
+</entry>
+ </row><row><entry
+ align="char">
+<para>ENOMEM</para>
+</entry><entry
+ align="char">
+<para>The driver failed to allocate enough memory.</para>
+</entry>
+ </row></tbody></tgroup></informaltable>
+</section>
+
+<section id="dmx_fclose">
+<title>close()</title>
+<para>DESCRIPTION
+</para>
+<informaltable><tgroup cols="1"><tbody><row><entry
+ align="char">
+<para>This system call deactivates and deallocates a filter that was previously
+ allocated via the open() call.</para>
+</entry>
+ </row></tbody></tgroup></informaltable>
+<para>SYNOPSIS
+</para>
+<informaltable><tgroup cols="1"><tbody><row><entry
+ align="char">
+<para>int close(int fd);</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></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 open file descriptor.</para>
+</entry>
+ </row></tbody></tgroup></informaltable>
+</section>
+
+<section id="dmx_fread">
+<title>read()</title>
+<para>DESCRIPTION
+</para>
+<informaltable><tgroup cols="1"><tbody><row><entry
+ align="char">
+<para>This system call returns filtered data, which might be section or PES data. The
+ filtered data is transferred from the driver&#8217;s internal circular buffer to buf. The
+ maximum amount of data to be transferred is implied by count.</para>
+</entry>
+ </row><row><entry
+ align="char">
+<para>When returning section data the driver always tries to return a complete single
+ section (even though buf would provide buffer space for more data). If the size
+ of the buffer is smaller than the section as much as possible will be returned,
+ and the remaining data will be provided in subsequent calls.</para>
+</entry>
+ </row><row><entry
+ align="char">
+<para>The size of the internal buffer is 2 * 4096 bytes (the size of two maximum
+ sized sections) by default. The size of this buffer may be changed by using the
+ DMX_SET_BUFFER_SIZE function. If the buffer is not large enough, or if
+ the read operations are not performed fast enough, this may result in a buffer
+ overflow error. In this case EOVERFLOW will be returned, and the circular
+ buffer will be emptied. This call is blocking if there is no data to return, i.e. the
+ process will be put to sleep waiting for data, unless the O_NONBLOCK flag
+ is specified.</para>
+</entry>
+ </row><row><entry
+ align="char">
+<para>Note that in order to be able to read, the filtering process has to be started
+ by defining either a section or a PES filter by means of the ioctl functions,
+ and then starting the filtering process via the DMX_START ioctl function
+ or by setting the DMX_IMMEDIATE_START flag. If the reading is done
+ from a logical DVR demux device, the data will constitute a Transport Stream
+ including the packets from all PES filters in the corresponding demux device
+ /dev/dvb/adapter0/demux0 having the output set to DMX_OUT_TS_TAP.</para>
+</entry>
+ </row></tbody></tgroup></informaltable>
+<para>SYNOPSIS
+</para>
+<informaltable><tgroup cols="1"><tbody><row><entry
+ align="char">
+<para>size_t read(int fd, void &#x22C6;buf, size_t count);</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>void *buf</para>
+</entry><entry
+ align="char">
+<para>Pointer to the buffer to be used for returned filtered data.</para>
+</entry>
+ </row><row><entry
+ align="char">
+<para>size_t count</para>
+</entry><entry
+ align="char">
+<para>Size of buf.</para>
+</entry>
+ </row></tbody></tgroup></informaltable>
+<para>ERRORS
+</para>
+<informaltable><tgroup cols="2"><tbody><row><entry
+ align="char">
+<para>EWOULDBLOCK</para>
+</entry><entry
+ align="char">
+<para>No data to return and O_NONBLOCK was specified.</para>
+</entry>
+ </row><row><entry
+ align="char">
+<para>EBADF</para>
+</entry><entry
+ align="char">
+<para>fd is not a valid open file descriptor.</para>
+</entry>
+ </row><row><entry
+ align="char">
+<para>ECRC</para>
+</entry><entry
+ align="char">
+<para>Last section had a CRC error - no data returned. The
+ buffer is flushed.</para>
+</entry>
+ </row><row><entry
+ align="char">
+<para>EOVERFLOW</para>
+</entry><entry
+ align="char">
+</entry>
+ </row><row><entry
+ align="char">
+</entry><entry
+ align="char">
+<para>The filtered data was not read from the buffer in due
+ time, resulting in non-read data being lost. The buffer is
+ flushed.</para>
+</entry>
+ </row><row><entry
+ align="char">
+<para>ETIMEDOUT</para>
+</entry><entry
+ align="char">
+<para>The section was not loaded within the stated timeout
+ period. See ioctl DMX_SET_FILTER for how to set a
+ timeout.</para>
+</entry>
+ </row><row><entry
+ align="char">
+<para>EFAULT</para>
+</entry><entry
+ align="char">
+<para>The driver failed to write to the callers buffer due to an
+ invalid *buf pointer.</para>
+</entry>
+ </row></tbody></tgroup></informaltable>
+</section>
+
+<section id="dmx_fwrite">
+<title>write()</title>
+<para>DESCRIPTION
+</para>
+<informaltable><tgroup cols="1"><tbody><row><entry
+ align="char">
+<para>This system call is only provided by the logical device /dev/dvb/adapter0/dvr0,
+ associated with the physical demux device that provides the actual DVR
+ functionality. It is used for replay of a digitally recorded Transport Stream.
+ Matching filters have to be defined in the corresponding physical demux
+ device, /dev/dvb/adapter0/demux0. The amount of data to be transferred is
+ implied by count.</para>
+</entry>
+ </row></tbody></tgroup></informaltable>
+<para>SYNOPSIS
+</para>
+<informaltable><tgroup cols="1"><tbody><row><entry
+ align="char">
+<para>ssize_t write(int fd, const void &#x22C6;buf, size_t
+ count);</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>void *buf</para>
+</entry><entry
+ align="char">
+<para>Pointer to the buffer containing the Transport Stream.</para>
+</entry>
+ </row><row><entry
+ align="char">
+<para>size_t count</para>
+</entry><entry
+ align="char">
+<para>Size of buf.</para>
+</entry>
+ </row></tbody></tgroup></informaltable>
+<para>ERRORS
+</para>
+<informaltable><tgroup cols="2"><tbody><row><entry
+ align="char">
+<para>EWOULDBLOCK</para>
+</entry><entry
+ align="char">
+<para>No data was written. This
+ might happen if O_NONBLOCK was specified and there
+ is no more buffer space available (if O_NONBLOCK is
+ not specified the function will block until buffer space is
+ available).</para>
+</entry>
+ </row><row><entry
+ align="char">
+<para>EBUSY</para>
+</entry><entry
+ align="char">
+<para>This error code indicates that there are conflicting
+ requests. The corresponding demux device is setup to
+ receive data from the front- end. Make sure that these
+ filters are stopped and that the filters with input set to
+ DMX_IN_DVR are started.</para>
+</entry>
+ </row><row><entry
+ align="char">
+<para>EBADF</para>
+</entry><entry
+ align="char">
+<para>fd is not a valid open file descriptor.</para>
+</entry>
+ </row></tbody></tgroup></informaltable>
+</section>
+
+<section id="dmx_start">
+<title>DMX_START</title>
+<para>DESCRIPTION
+</para>
+<informaltable><tgroup cols="1"><tbody><row><entry
+ align="char">
+<para>This ioctl call is used to start the actual filtering operation defined via the ioctl
+ calls DMX_SET_FILTER or DMX_SET_PES_FILTER.</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_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 &#8221;one-shot&#8221; 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 &#x22C6;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 &#x22C6;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 &#x22C6;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-&#x003E;stc /
+ stc-&#x003E;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 &#x22C6;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>