diff options
Diffstat (limited to 'dvb-spec/dvbapi/demux.tex')
| -rw-r--r-- | dvb-spec/dvbapi/demux.tex | 151 |
1 files changed, 91 insertions, 60 deletions
diff --git a/dvb-spec/dvbapi/demux.tex b/dvb-spec/dvbapi/demux.tex index 541ee633a..882463090 100644 --- a/dvb-spec/dvbapi/demux.tex +++ b/dvb-spec/dvbapi/demux.tex @@ -1,16 +1,14 @@ \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}. +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} -\begin{verbatim} -typedef uint16_t dvb_pid_t; -\end{verbatim} - -\devsubsubsec{dmxOutput\_t} +\devsubsubsec{dmx\_output\_t} \label{dmxoutput} \begin{verbatim} @@ -19,26 +17,30 @@ typedef enum DMX_OUT_DECODER, DMX_OUT_TAP, DMX_OUT_TS_TAP -} dmxOutput_t; +} dmx_output_t; \end{verbatim} -/* Output multiplexed into a new TS */ -/* (to be retrieved by reading from the */ -/* logical DVR device). */ + +\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{dmxInput\_t} +\devsubsubsec{dmx\_input\_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; + DMX_IN_FRONTEND, + DMX_IN_DVR +} dmx_input_t; \end{verbatim} -\devsubsubsec{dmxPesType\_t} +\devsubsubsec{dmx\_pes\_type\_t} \label{dmxpestype} \begin{verbatim} @@ -50,11 +52,11 @@ typedef enum DMX_PES_SUBTITLE, DMX_PES_PCR, DMX_PES_OTHER -} dmxPesType_t; +} dmx_pes_type_t; \end{verbatim} -\devsubsubsec{dmxEvent\_t} +\devsubsubsec{dmx\_event\_t} \label{dmxeventt} \begin{verbatim} @@ -62,11 +64,11 @@ typedef enum { DMX_SCRAMBLING_EV, DMX_FRONTEND_EV -} dmxEvent_t; +} dmx_event_t; \end{verbatim} -\devsubsubsec{dmxScramblingStatus\_t} +\devsubsubsec{dmx\_scrambling\_status\_t} \label{dmxscramblingstatus} \begin{verbatim} @@ -74,32 +76,32 @@ typedef enum { DMX_SCRAMBLING_OFF, DMX_SCRAMBLING_ON -} dmxScramblingStatus_t; +} dmx_scrambling_status_t; \end{verbatim} -\devsubsubsec{dmxFilter\_t} +\devsubsubsec{struct dmx\_filter} \label{dmxfilter} \begin{verbatim} -typedef struct dmxFilter +typedef struct dmx_filter { uint8_t filter[DMX_FILTER_SIZE]; uint8_t mask[DMX_FILTER_SIZE]; -} dmxFilter_t; +} dmx_filter_t; \end{verbatim} -\devsubsubsec{dmxSctFilterParams} +\devsubsubsec{struct dmx\_sct\_filter\_params} \label{dmxsctfilterparams} \begin{verbatim} -struct dmxSctFilterParams +struct dmx_sct_filter_params { - dvb_pid_t pid; - dmxFilter_t filter; - uint32_t timeout; - uint32_t flags; + 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 @@ -107,51 +109,61 @@ struct dmxSctFilterParams \end{verbatim} -\devsubsubsec{dmxPesFilterParams} +\devsubsubsec{struct dmx\_pes\_filter\_params} \label{dmxpesfilterparams} \begin{verbatim} -struct dmxPesFilterParams +struct dmx_pes_filter_params { - dvb_pid_t pid; - dmxInput_t input; - dmxOutput_t output; - dmxPesType_t pesType; - uint32_t flags; + uint16_t pid; + dmx_input_t input; + dmx_output_t output; + dmx_pes_type_t pes_type; + uint32_t flags; }; \end{verbatim} -\devsubsubsec{dmxEvent} +\devsubsubsec{struct dmx\_event} \label{dmxevent} \begin{verbatim} -struct dmxEvent +struct dmx_event { - dmxEvent_t event; - time_t timeStamp; + dmx_event_t event; + time_t timeStamp; union { - dmxScramblingStatus_t scrambling; + 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/ost/demuxn, where n - denotes the specific demux device to be opened, allocates a new filter + 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/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 + /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/ost/demuxn) + 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. @@ -200,7 +212,7 @@ struct dmxEvent 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, + 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 @@ -211,7 +223,7 @@ struct dmxEvent 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 + 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().\\ @@ -222,7 +234,7 @@ struct dmxEvent EBADF & fd is not a valid open file descriptor.\\ ECRC & Last section had a CRC error - no data returned. The buffer is flushed.\\ - EBUFFEROVERFLOW & \\ + EOVERFLOW & \\ & The filtered data was not read from the buffer in due time, resulting in non-read data being lost. The buffer is flushed.\\ @@ -236,11 +248,11 @@ struct dmxEvent \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 + 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/ost/demuxn. + 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().\\ @@ -295,7 +307,7 @@ struct dmxEvent } \ifunction{DMX\_SET\_FILTER}{ - int ioctl( int fd, int request = DMX\_SET\_FILTER, struct dmxSctFilterParams *params); + 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 @@ -310,7 +322,7 @@ struct dmxEvent }{ int fd & File descriptor returned by a previous call to open().\\ int request & Equals DMX\_SET\_FILTER for this command.\\ - struct dmxSctFilterParams *params + struct dmx\_sct\_filter\_params *params & Pointer to structure containing filter parameters.\\ }{ EBADF & fd is not a valid file descriptor.\\ @@ -319,7 +331,7 @@ struct dmxEvent \ifunction{DMX\_SET\_PES\_FILTER}{ int ioctl( int fd, int request = DMX\_SET\_PES\_FILTER, - struct dmxPesFilterParams *params); + 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 @@ -335,7 +347,7 @@ struct dmxEvent }{ int fd & File descriptor returned by a previous call to open().\\ int request & Equals DMX\_SET\_PES\_FILTER for this command.\\ - struct dmxPesFilterParams *params + struct dmx\_pes\_filter\_params *params & Pointer to structure containing filter parameters.\\ }{ EBADF & fd is not a valid file descriptor.\\ @@ -364,9 +376,9 @@ struct dmxEvent } \ifunction{DMX\_GET\_EVENT}{ - int ioctl( int fd, int request = DMX\_GET\_EVENT, struct dmxEvent *ev); + 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 + 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 @@ -379,13 +391,32 @@ struct dmxEvent }{ 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.\\ + 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" |