3.1. Demux Data Types¶
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enum dmx_output¶
Output for the demux.
Constants
DMX_OUT_DECODER
Streaming directly to decoder.
DMX_OUT_TAP
Output going to a memory buffer (to be retrieved via the read command). Delivers the stream output to the demux device on which the ioctl is called.
DMX_OUT_TS_TAP
Output multiplexed into a new TS (to be retrieved by reading from the logical DVR device). Routes output to the logical DVR device
/dev/dvb/adapter?/dvr?, which delivers a TS multiplexed from all filters for which DMX_OUT_TS_TAP was specified.
DMX_OUT_TSDEMUX_TAP
Like DMX_OUT_TS_TAP but retrieved from the DMX device.
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enum dmx_input¶
Input from the demux.
Constants
DMX_IN_FRONTENDInput from a front-end device.
DMX_IN_DVRInput from the logical DVR device.
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enum dmx_ts_pes¶
type of the PES filter.
Constants
DMX_PES_AUDIO0first audio PID. Also referred as DMX_PES_AUDIO.
DMX_PES_VIDEO0first video PID. Also referred as DMX_PES_VIDEO.
DMX_PES_TELETEXT0first teletext PID. Also referred as DMX_PES_TELETEXT.
DMX_PES_SUBTITLE0first subtitle PID. Also referred as DMX_PES_SUBTITLE.
DMX_PES_PCR0first Program Clock Reference PID. Also referred as DMX_PES_PCR.
DMX_PES_AUDIO1second audio PID.
DMX_PES_VIDEO1second video PID.
DMX_PES_TELETEXT1second teletext PID.
DMX_PES_SUBTITLE1second subtitle PID.
DMX_PES_PCR1second Program Clock Reference PID.
DMX_PES_AUDIO2third audio PID.
DMX_PES_VIDEO2third video PID.
DMX_PES_TELETEXT2third teletext PID.
DMX_PES_SUBTITLE2third subtitle PID.
DMX_PES_PCR2third Program Clock Reference PID.
DMX_PES_AUDIO3fourth audio PID.
DMX_PES_VIDEO3fourth video PID.
DMX_PES_TELETEXT3fourth teletext PID.
DMX_PES_SUBTITLE3fourth subtitle PID.
DMX_PES_PCR3fourth Program Clock Reference PID.
DMX_PES_OTHERany other PID.
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struct dmx_filter¶
Specifies a section header filter.
Definition:
struct dmx_filter {
__u8 filter[DMX_FILTER_SIZE];
__u8 mask[DMX_FILTER_SIZE];
__u8 mode[DMX_FILTER_SIZE];
};
Members
filterbit array with bits to be matched at the section header.
maskbits that are valid at the filter bit array.
modemode of match: if bit is zero, it will match if equal (positive match); if bit is one, it will match if the bit is negated.
Note
All arrays in this struct have a size of DMX_FILTER_SIZE (16 bytes).
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struct dmx_sct_filter_params¶
Specifies a section filter.
Definition:
struct dmx_sct_filter_params {
__u16 pid;
struct dmx_filter filter;
__u32 timeout;
__u32 flags;
#define DMX_CHECK_CRC 1;
#define DMX_ONESHOT 2;
#define DMX_IMMEDIATE_START 4;
};
Members
pidPID to be filtered.
filtersection header filter, as defined by
struct dmx_filter.timeoutmaximum time to filter, in milliseconds.
flagsextra flags for the section filter.
Description
Carries the configuration for a MPEG-TS section filter.
The flags can be:
DMX_CHECK_CRC- only deliver sections where the CRC check succeeded;
DMX_ONESHOT- disable the section filter after one section has been delivered;
DMX_IMMEDIATE_START- Start filter immediately without requiring a DMX_START.
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struct dmx_pes_filter_params¶
Specifies Packetized Elementary Stream (PES) filter parameters.
Definition:
struct dmx_pes_filter_params {
__u16 pid;
enum dmx_input input;
enum dmx_output output;
enum dmx_ts_pes pes_type;
__u32 flags;
};
Members
pidPID to be filtered.
inputDemux input, as specified by
enum dmx_input.outputDemux output, as specified by
enum dmx_output.pes_typeType of the pes filter, as specified by
enum dmx_pes_type.flagsDemux PES flags.
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struct dmx_stc¶
Stores System Time Counter (STC) information.
Definition:
struct dmx_stc {
unsigned int num;
unsigned int base;
__u64 stc;
};
Members
numinput data: number of the STC, from 0 to N.
baseoutput: divisor for STC to get 90 kHz clock.
stcoutput: stc in base * 90 kHz units.
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enum dmx_buffer_flags¶
DMX memory-mapped buffer flags
Constants
DMX_BUFFER_FLAG_HAD_CRC32_DISCARD
Indicates that the Kernel discarded one or more frames due to wrong CRC32 checksum.
DMX_BUFFER_FLAG_TEI
Indicates that the Kernel has detected a Transport Error indicator (TEI) on a filtered pid.
DMX_BUFFER_PKT_COUNTER_MISMATCH
Indicates that the Kernel has detected a packet counter mismatch on a filtered pid.
DMX_BUFFER_FLAG_DISCONTINUITY_DETECTED
Indicates that the Kernel has detected one or more frame discontinuity.
DMX_BUFFER_FLAG_DISCONTINUITY_INDICATOR
Received at least one packet with a frame discontinuity indicator.
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struct dmx_buffer¶
dmx buffer info
Definition:
struct dmx_buffer {
__u32 index;
__u32 bytesused;
__u32 offset;
__u32 length;
__u32 flags;
__u32 count;
};
Members
indexid number of the buffer
bytesusednumber of bytes occupied by data in the buffer (payload);
offsetfor buffers with memory == DMX_MEMORY_MMAP; offset from the start of the device memory for this plane, (or a “cookie” that should be passed to mmap() as offset)
lengthsize in bytes of the buffer
flagsbit array of buffer flags as defined by
enum dmx_buffer_flags. Filled only atDMX_DQBUF.countmonotonic counter for filled buffers. Helps to identify data stream loses. Filled only at
DMX_DQBUF.
Description
Contains data exchanged by application and driver using one of the streaming I/O methods.
Please notice that, for DMX_QBUF, only index should be filled.
On DMX_DQBUF calls, all fields will be filled by the Kernel.
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struct dmx_requestbuffers¶
request dmx buffer information
Definition:
struct dmx_requestbuffers {
__u32 count;
__u32 size;
};
Members
countnumber of requested buffers,
sizesize in bytes of the requested buffer
Description
Contains data used for requesting a dmx buffer. All reserved fields must be set to zero.
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struct dmx_exportbuffer¶
export of dmx buffer as DMABUF file descriptor
Definition:
struct dmx_exportbuffer {
__u32 index;
__u32 flags;
__s32 fd;
};
Members
indexid number of the buffer
flagsflags for newly created file, currently only O_CLOEXEC is supported, refer to manual of open syscall for more details
fdfile descriptor associated with DMABUF (set by driver)
Description
Contains data used for exporting a dmx buffer as DMABUF file descriptor. The buffer is identified by a ‘cookie’ returned by DMX_QUERYBUF (identical to the cookie used to mmap() the buffer to userspace). All reserved fields must be set to zero. The field reserved0 is expected to become a structure ‘type’ allowing an alternative layout of the structure content. Therefore this field should not be used for any other extensions.