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Diffstat (limited to 'dvb-spec/dvbapi/demux.tex')
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diff --git a/dvb-spec/dvbapi/demux.tex b/dvb-spec/dvbapi/demux.tex deleted file mode 100644 index 882463090..000000000 --- a/dvb-spec/dvbapi/demux.tex +++ /dev/null @@ -1,423 +0,0 @@ -\devsec{DVB Demux Device} - -The DVB demux device controls the filters of the DVB hardware/software. -It can be accessed through \texttt{/dev/adapter0/demux0}. -Data types and and ioctl definitions can be accessed by including -\texttt{linux/dvb/dmx.h} in your application. - -\devsubsec{Demux Data Types} - - -\devsubsubsec{dmx\_output\_t} -\label{dmxoutput} - -\begin{verbatim} -typedef enum -{ - DMX_OUT_DECODER, - DMX_OUT_TAP, - DMX_OUT_TS_TAP -} dmx_output_t; -\end{verbatim} - -\noindent\texttt{DMX\_OUT\_TAP} delivers the stream output to the demux device -on which the ioctl is called. - -\noindent\texttt{DMX\_OUT\_TS\_TAP} routes output to the logical DVR device -\texttt{/dev/dvb/adapter0/dvr0}, which delivers a TS multiplexed from -all filters for which \texttt{DMX\_OUT\_TS\_TAP} was specified. - - -\devsubsubsec{dmx\_input\_t} -\label{dmxinput} - -\begin{verbatim} -typedef enum -{ - DMX_IN_FRONTEND, - DMX_IN_DVR -} dmx_input_t; -\end{verbatim} - - -\devsubsubsec{dmx\_pes\_type\_t} -\label{dmxpestype} - -\begin{verbatim} -typedef enum -{ - DMX_PES_AUDIO, - DMX_PES_VIDEO, - DMX_PES_TELETEXT, - DMX_PES_SUBTITLE, - DMX_PES_PCR, - DMX_PES_OTHER -} dmx_pes_type_t; -\end{verbatim} - - -\devsubsubsec{dmx\_event\_t} -\label{dmxeventt} - -\begin{verbatim} -typedef enum -{ - DMX_SCRAMBLING_EV, - DMX_FRONTEND_EV -} dmx_event_t; -\end{verbatim} - - -\devsubsubsec{dmx\_scrambling\_status\_t} -\label{dmxscramblingstatus} - -\begin{verbatim} -typedef enum -{ - DMX_SCRAMBLING_OFF, - DMX_SCRAMBLING_ON -} dmx_scrambling_status_t; -\end{verbatim} - - -\devsubsubsec{struct dmx\_filter} -\label{dmxfilter} - -\begin{verbatim} -typedef struct dmx_filter -{ - uint8_t filter[DMX_FILTER_SIZE]; - uint8_t mask[DMX_FILTER_SIZE]; -} dmx_filter_t; -\end{verbatim} - - -\devsubsubsec{struct dmx\_sct\_filter\_params} -\label{dmxsctfilterparams} - -\begin{verbatim} -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 -}; -\end{verbatim} - - -\devsubsubsec{struct dmx\_pes\_filter\_params} -\label{dmxpesfilterparams} - -\begin{verbatim} -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; -}; -\end{verbatim} - - -\devsubsubsec{struct dmx\_event} -\label{dmxevent} - -\begin{verbatim} -struct dmx_event -{ - dmx_event_t event; - time_t timeStamp; - union - { - dmx_scrambling_status_t scrambling; - } u; -}; -\end{verbatim} - -\devsubsubsec{struct dmx\_stc} -\label{dmxstc} - -\begin{verbatim} -struct dmx_stc { - unsigned int num; /* input : which STC? 0..N */ - unsigned int base; /* output: divisor for stc to get 90 kHz clock */ - uint64_t stc; /* output: stc in 'base'*90 kHz units */ -}; -\end{verbatim} - -\clearpage - -\devsubsec{Demux Function Calls} -\function{open()}{ - int open(const char *deviceName, int flags);}{ - 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. -% This device can only be opened in read-write mode. - - 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. - }{ - const char *deviceName & Name of demux device.\\ - int flags & A bit-wise OR of the following flags:\\ - & \hspace{1em} O\_RDWR read/write access\\ - & \hspace{1em} O\_NONBLOCK open in non-blocking mode \\ - & \hspace{1em} (blocking mode is the default)\\ - }{ - ENODEV & Device driver not loaded/available.\\ - EINVAL & Invalid argument.\\ - EMFILE & ``Too many open files'', i.e. no more filters available.\\ - ENOMEM & The driver failed to allocate enough memory.\\ -} - -\function{close()}{ - int close(int fd);}{ - This system call deactivates and deallocates a filter that was previously - allocated via the open() call. - }{ - int fd & File descriptor returned by a previous call to open().\\ - }{ - EBADF & fd is not a valid open file descriptor.\\ -} - -\function{read()}{ - size\_t read(int fd, void *buf, size\_t count); - }{ - This system call returns filtered data, which might be section or PES - data. The filtered data is transferred from the driver's internal circular - buffer to buf. The maximum amount of data to be transferred is implied by - count.\\ - 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.\\ - 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.\\ - 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. - }{ - int fd & File descriptor returned by a previous call to open().\\ - void *buf & Pointer to the buffer to be used for returned filtered data.\\ - size\_t count & Size of buf.\\ - }{ - EWOULDBLOCK & No data to return and O\_NONBLOCK was specified.\\ - EBADF & fd is not a valid open file descriptor.\\ - ECRC & Last section had a CRC error - no data returned. - The buffer is flushed.\\ - EOVERFLOW & \\ -& The filtered data was not read from the buffer in - due time, resulting in non-read data being lost. - The buffer is flushed.\\ - ETIMEDOUT & The section was not loaded within the stated - timeout period. See ioctl DMX\_SET\_FILTER for - how to set a timeout.\\ - EFAULT & The driver failed to write to the callers buffer - due to an invalid *buf pointer.\\ -} - -\function{write()}{ - ssize\_t write(int fd, const void *buf, size\_t count); - }{ - 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. - }{ - int fd & File descriptor returned by a previous call to open().\\ - void *buf & Pointer to the buffer containing the Transport Stream.\\ - size\_t count & Size of buf.\\ - }{ - EWOULDBLOCK & 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).\\ - EBUSY & 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.\\ - EBADF & fd is not a valid open file descriptor.\\ -} - -\ifunction{DMX\_START}{ - int ioctl( int fd, int request = DMX\_START); - }{ - This ioctl call is used to start the actual filtering operation - defined via the ioctl calls DMX\_SET\_FILTER or DMX\_SET\_PES\_FILTER. - }{ - int fd & File descriptor returned by a previous call to open().\\ - int request & Equals DMX\_START for this command.\\ - }{ - EBADF & fd is not a valid file descriptor.\\ - EINVAL & Invalid argument, i.e. no filtering parameters - provided via the DMX\_SET\_FILTER or - DMX\_SET\_PES\_FILTER functions.\\ - EBUSY & 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.\\ -} - -\ifunction{DMX\_STOP}{ - int ioctl( int fd, int request = DMX\_STOP); - }{ - 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. - }{ - int fd & File descriptor returned by a previous call to open().\\ - int request & Equals DMX\_STOP for this command.\\ - }{ - EBADF & fd is not a valid file descriptor.\\ -} - -\ifunction{DMX\_SET\_FILTER}{ - int ioctl( int fd, int request = DMX\_SET\_FILTER, struct dmx\_sct\_filter\_params *params); - }{ - 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. - }{ - int fd & File descriptor returned by a previous call to open().\\ - int request & Equals DMX\_SET\_FILTER for this command.\\ - struct dmx\_sct\_filter\_params *params - & Pointer to structure containing filter parameters.\\ - }{ - EBADF & fd is not a valid file descriptor.\\ - EINVAL & Invalid argument.\\ -} - -\ifunction{DMX\_SET\_PES\_FILTER}{ - int ioctl( int fd, int request = DMX\_SET\_PES\_FILTER, - struct dmx\_pes\_filter\_params *params); - }{ - 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.\\ - 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. - }{ - int fd & File descriptor returned by a previous call to open().\\ - int request & Equals DMX\_SET\_PES\_FILTER for this command.\\ - struct dmx\_pes\_filter\_params *params - & Pointer to structure containing filter parameters.\\ - }{ - EBADF & fd is not a valid file descriptor.\\ - EINVAL & Invalid argument.\\ - EBUSY & 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.\\ -} - -\ifunction{DMX\_SET\_BUFFER\_SIZE}{ - int ioctl( int fd, int request = DMX\_SET\_BUFFER\_SIZE, unsigned long size); - }{ - 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. - }{ - int fd & File descriptor returned by a previous call to open().\\ - int request & Equals DMX\_SET\_BUFFER\_SIZE for this command.\\ - unsigned long size & Size of circular buffer.\\ - }{ - EBADF & fd is not a valid file descriptor.\\ - ENOMEM & The driver was not able to allocate a buffer of the requested size.\\ -} - -\ifunction{DMX\_GET\_EVENT}{ - int ioctl( int fd, int request = DMX\_GET\_EVENT, struct dmx\_event *ev); - }{ - 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.\\ - 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. - }{ - int fd & File descriptor returned by a previous call to open().\\ - int request & Equals DMX\_GET\_EVENT for this command.\\ - struct dmx\_event *ev & Pointer to the location where the event is to be stored.\\ - }{ - EBADF & fd is not a valid file descriptor.\\ - EFAULT & ev points to an invalid address.\\ - EWOULDBLOCK & There is no event pending, and the device is in non-blocking mode.\\ -} - -\ifunction{DMX\_GET\_STC}{ - int ioctl( int fd, int request = DMX\_GET\_STC, struct dmx\_stc *stc); - }{ - 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 \begin{ttfamily}stc->stc / stc->base\end{ttfamily}. - }{ - int fd & File descriptor returned by a previous call to open().\\ - int request & Equals DMX\_GET\_STC for this command.\\ - struct dmx\_stc *stc & Pointer to the location where the stc is to be stored.\\ - }{ - EBADF & fd is not a valid file descriptor.\\ - EFAULT & stc points to an invalid address.\\ - EINVAL & Invalid stc number.\\ -} - -%%% Local Variables: -%%% mode: latex -%%% TeX-master: "dvbapi" -%%% End: |