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Diffstat (limited to 'dvb-spec/dvbapi/demux.tex')
| -rw-r--r-- | dvb-spec/dvbapi/demux.tex | 392 |
1 files changed, 0 insertions, 392 deletions
diff --git a/dvb-spec/dvbapi/demux.tex b/dvb-spec/dvbapi/demux.tex deleted file mode 100644 index 541ee633a..000000000 --- a/dvb-spec/dvbapi/demux.tex +++ /dev/null @@ -1,392 +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/ost/demux}. - -\devsubsec{Demux Data Types} - -\begin{verbatim} -typedef uint16_t dvb_pid_t; -\end{verbatim} - - -\devsubsubsec{dmxOutput\_t} -\label{dmxoutput} - -\begin{verbatim} -typedef enum -{ - DMX_OUT_DECODER, - DMX_OUT_TAP, - DMX_OUT_TS_TAP -} dmxOutput_t; -\end{verbatim} -/* Output multiplexed into a new TS */ -/* (to be retrieved by reading from the */ -/* logical DVR device). */ - - -\devsubsubsec{dmxInput\_t} -\label{dmxinput} - -\begin{verbatim} -typedef enum -{ - DMX_IN_FRONTEND, /* Input from a front-end device. */ - DMX_IN_DVR /* Input from the logical DVR device. */ -} dmxInput_t; -\end{verbatim} - - -\devsubsubsec{dmxPesType\_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 -} dmxPesType_t; -\end{verbatim} - - -\devsubsubsec{dmxEvent\_t} -\label{dmxeventt} - -\begin{verbatim} -typedef enum -{ - DMX_SCRAMBLING_EV, - DMX_FRONTEND_EV -} dmxEvent_t; -\end{verbatim} - - -\devsubsubsec{dmxScramblingStatus\_t} -\label{dmxscramblingstatus} - -\begin{verbatim} -typedef enum -{ - DMX_SCRAMBLING_OFF, - DMX_SCRAMBLING_ON -} dmxScramblingStatus_t; -\end{verbatim} - - -\devsubsubsec{dmxFilter\_t} -\label{dmxfilter} - -\begin{verbatim} -typedef struct dmxFilter -{ - uint8_t filter[DMX_FILTER_SIZE]; - uint8_t mask[DMX_FILTER_SIZE]; -} dmxFilter_t; -\end{verbatim} - - -\devsubsubsec{dmxSctFilterParams} -\label{dmxsctfilterparams} - -\begin{verbatim} -struct dmxSctFilterParams -{ - dvb_pid_t pid; - dmxFilter_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{dmxPesFilterParams} -\label{dmxpesfilterparams} - -\begin{verbatim} -struct dmxPesFilterParams -{ - dvb_pid_t pid; - dmxInput_t input; - dmxOutput_t output; - dmxPesType_t pesType; - uint32_t flags; -}; -\end{verbatim} - - -\devsubsubsec{dmxEvent} -\label{dmxevent} - -\begin{verbatim} -struct dmxEvent -{ - dmxEvent_t event; - time_t timeStamp; - union - { - dmxScramblingStatus_t scrambling; - } u; -}; -\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/ost/demuxn, where n - denotes the specific demux device to be opened, 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/ost/dvrn is a logical device to be used for retrieving Transport - Streams for digital video recording. n identifies the physical demux - device that provides the actual DVR functionality. When reading from - this device a transport stream containing the packets from all PES - filters set in the corresponding demux device (/dev/ost/demuxn) - 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 EBUFFEROVERFLOW 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/ost/demuxn 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.\\ - EBUFFEROVERFLOW & \\ -& 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/ost/dvrn, - where n identifies 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/ost/demuxn. - 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 dmxSctFilterParams *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 dmxSctFilterParams *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 dmxPesFilterParams *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 dmxPesFilterParams *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 dmxEvent *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 dmxEvent *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.\\ -} - -%%% Local Variables: -%%% mode: latex -%%% TeX-master: "dvbapi" -%%% End: |