FE_GET_PROPERTY/FE_SET_PROPERTYThis section describes the DVB version 5 extention of the DVB-API, also
called "S2API", as this API were added to provide support for DVB-S2. It was
designed to be able to replace the old frontend API. Yet, the DISEQC and
the capability ioctls weren't implemented yet via the new way.The typical usage for the FE_GET_PROPERTY/FE_SET_PROPERTY
API is to replace the ioctl's were the
struct dvb_frontend_parameters were used.DTV property type
/* Reserved fields should be set to 0 */
struct dtv_property {
__u32 cmd;
union {
__u32 data;
struct {
__u8 data[32];
__u32 len;
__u32 reserved1[3];
void *reserved2;
} buffer;
} u;
int result;
} __attribute__ ((packed));
/* num of properties cannot exceed DTV_IOCTL_MAX_MSGS per ioctl */
#define DTV_IOCTL_MAX_MSGS 64
DTV properties type
struct dtv_properties {
__u32 num;
struct dtv_property *props;
};
FE_GET_PROPERTYDESCRIPTION
This ioctl call returns one or more frontend properties. This call only
requires read-only access to the device.SYNOPSIS
int ioctl(int fd, int request = FE_GET_PROPERTY,
dtv_properties ⋆props);PARAMETERS
int fdFile descriptor returned by a previous call to open().int numEquals FE_GET_PROPERTY for this command.struct dtv_property *propsPoints to the location where the front-end property commands are stored.
&return-value-dvb;
EINVALInvalid parameter(s) received or number of parameters out of the range.ENOMEMOut of memory.EFAULTFailure while copying data from/to userspace.EOPNOTSUPPProperty type not supported.FE_SET_PROPERTYDESCRIPTION
This ioctl call sets one or more frontend properties. This call only
requires read-only access to the device.SYNOPSIS
int ioctl(int fd, int request = FE_SET_PROPERTY,
dtv_properties ⋆props);PARAMETERS
int fdFile descriptor returned by a previous call to open().int numEquals FE_SET_PROPERTY for this command.struct dtv_property *propsPoints to the location where the front-end property commands are stored.
&return-value-dvb;
EINVALInvalid parameter(s) received or number of parameters out of the range.ENOMEMOut of memory.EFAULTFailure while copying data from/to userspace.EOPNOTSUPPProperty type not supported.Property types
On FE_GET_PROPERTY/FE_SET_PROPERTY,
the actual action is determined by the dtv_property cmd/data pairs. With one single ioctl, is possible to
get/set up to 64 properties. The actual meaning of each property is described on the next sections.
The available frontend property types are shown on the next section.Digital TV property parametersDTV_UNDEFINEDUsed internally. A GET/SET operation for it won't change or return anything.DTV_TUNEInterpret the cache of data, build either a traditional frontend tunerequest so we can pass validation in the FE_SET_FRONTEND ioctl.DTV_CLEARReset a cache of data specific to the frontend here. This does not effect hardware.DTV_FREQUENCYCentral frequency of the channel, in HZ.Notes:1)For ISDB-T, the channels are usually transmitted with an offset of 143kHz.
E.g. a valid frequncy could be 474143 kHz. The stepping is bound to the bandwidth of
the channel which is 6MHz.2)As in ISDB-Tsb the channel consists of only one or three segments the
frequency step is 429kHz, 3*429 respectively. As for ISDB-T the
central frequency of the channel is expected.DTV_MODULATIONSpecifies the frontend modulation type for cable and satellite types. The modulation can be one of the types bellow:
typedef enum fe_modulation {
QPSK,
QAM_16,
QAM_32,
QAM_64,
QAM_128,
QAM_256,
QAM_AUTO,
VSB_8,
VSB_16,
PSK_8,
APSK_16,
APSK_32,
DQPSK,
} fe_modulation_t;
DTV_BANDWIDTH_HZBandwidth for the channel, in HZ.Possible values:
1712000,
5000000,
6000000,
7000000,
8000000,
10000000.
Notes:1) For ISDB-T it should be always 6000000Hz (6MHz)2) For ISDB-Tsb it can vary depending on the number of connected segments3) Bandwidth doesn't apply for DVB-C transmissions, as the bandwidth
for DVB-C depends on the symbol rate4) Bandwidth in ISDB-T is fixed (6MHz) or can be easily derived from
other parameters (DTV_ISDBT_SB_SEGMENT_IDX,
DTV_ISDBT_SB_SEGMENT_COUNT).5) DVB-T supports 6, 7 and 8MHz.6) In addition, DVB-T2 supports 1.172, 5 and 10MHz.DTV_INVERSIONThe Inversion field can take one of these values:
typedef enum fe_spectral_inversion {
INVERSION_OFF,
INVERSION_ON,
INVERSION_AUTO
} fe_spectral_inversion_t;
It indicates if spectral inversion should be presumed or not. In the automatic setting
(INVERSION_AUTO) the hardware will try to figure out the correct setting by
itself.
DTV_DISEQC_MASTERCurrently not implemented.DTV_SYMBOL_RATEDigital TV symbol rate, in bauds (symbols/second). Used on cable standards.DTV_INNER_FECUsed cable/satellite transmissions. The acceptable values are:
typedef enum fe_code_rate {
FEC_NONE = 0,
FEC_1_2,
FEC_2_3,
FEC_3_4,
FEC_4_5,
FEC_5_6,
FEC_6_7,
FEC_7_8,
FEC_8_9,
FEC_AUTO,
FEC_3_5,
FEC_9_10,
} fe_code_rate_t;
which correspond to error correction rates of 1/2, 2/3, etc.,
no error correction or auto detection.DTV_VOLTAGEThe voltage is usually used with non-DiSEqC capable LNBs to switch
the polarzation (horizontal/vertical). When using DiSEqC epuipment this
voltage has to be switched consistently to the DiSEqC commands as
described in the DiSEqC spec.
typedef enum fe_sec_voltage {
SEC_VOLTAGE_13,
SEC_VOLTAGE_18
} fe_sec_voltage_t;
DTV_TONECurrently not used.DTV_PILOTSets DVB-S2 pilotfe_pilot type
typedef enum fe_pilot {
PILOT_ON,
PILOT_OFF,
PILOT_AUTO,
} fe_pilot_t;
DTV_ROLLOFFSets DVB-S2 rollofffe_rolloff type
typedef enum fe_rolloff {
ROLLOFF_35, /* Implied value in DVB-S, default for DVB-S2 */
ROLLOFF_20,
ROLLOFF_25,
ROLLOFF_AUTO,
} fe_rolloff_t;
DTV_DISEQC_SLAVE_REPLYCurrently not implemented.DTV_FE_CAPABILITY_COUNTCurrently not implemented.DTV_FE_CAPABILITYCurrently not implemented.DTV_DELIVERY_SYSTEMSpecifies the type of Delivery systemfe_delivery_system typePossible values:
typedef enum fe_delivery_system {
SYS_UNDEFINED,
SYS_DVBC_ANNEX_AC,
SYS_DVBC_ANNEX_B,
SYS_DVBT,
SYS_DSS,
SYS_DVBS,
SYS_DVBS2,
SYS_DVBH,
SYS_ISDBT,
SYS_ISDBS,
SYS_ISDBC,
SYS_ATSC,
SYS_ATSCMH,
SYS_DMBTH,
SYS_CMMB,
SYS_DAB,
SYS_DVBT2,
} fe_delivery_system_t;
DTV_ISDBT_PARTIAL_RECEPTIONIf DTV_ISDBT_SOUND_BROADCASTING is '0' this bit-field represents whether
the channel is in partial reception mode or not.If '1' DTV_ISDBT_LAYERA_* values are assigned to the center segment and
DTV_ISDBT_LAYERA_SEGMENT_COUNT has to be '1'.If in addition DTV_ISDBT_SOUND_BROADCASTING is '1'
DTV_ISDBT_PARTIAL_RECEPTION represents whether this ISDB-Tsb channel
is consisting of one segment and layer or three segments and two layers.Possible values: 0, 1, -1 (AUTO)DTV_ISDBT_SOUND_BROADCASTINGThis field represents whether the other DTV_ISDBT_*-parameters are
referring to an ISDB-T and an ISDB-Tsb channel. (See also
DTV_ISDBT_PARTIAL_RECEPTION).Possible values: 0, 1, -1 (AUTO)DTV_ISDBT_SB_SUBCHANNEL_IDThis field only applies if DTV_ISDBT_SOUND_BROADCASTING is '1'.(Note of the author: This might not be the correct description of the
SUBCHANNEL-ID in all details, but it is my understanding of the technical
background needed to program a device)An ISDB-Tsb channel (1 or 3 segments) can be broadcasted alone or in a
set of connected ISDB-Tsb channels. In this set of channels every
channel can be received independently. The number of connected
ISDB-Tsb segment can vary, e.g. depending on the frequency spectrum
bandwidth available.Example: Assume 8 ISDB-Tsb connected segments are broadcasted. The
broadcaster has several possibilities to put those channels in the
air: Assuming a normal 13-segment ISDB-T spectrum he can align the 8
segments from position 1-8 to 5-13 or anything in between.The underlying layer of segments are subchannels: each segment is
consisting of several subchannels with a predefined IDs. A sub-channel
is used to help the demodulator to synchronize on the channel.An ISDB-T channel is always centered over all sub-channels. As for
the example above, in ISDB-Tsb it is no longer as simple as that.The DTV_ISDBT_SB_SUBCHANNEL_ID parameter is used to give the
sub-channel ID of the segment to be demodulated.Possible values: 0 .. 41, -1 (AUTO)DTV_ISDBT_SB_SEGMENT_IDXThis field only applies if DTV_ISDBT_SOUND_BROADCASTING is '1'.DTV_ISDBT_SB_SEGMENT_IDX gives the index of the segment to be
demodulated for an ISDB-Tsb channel where several of them are
transmitted in the connected manner.Possible values: 0 .. DTV_ISDBT_SB_SEGMENT_COUNT - 1Note: This value cannot be determined by an automatic channel search.DTV_ISDBT_SB_SEGMENT_COUNTThis field only applies if DTV_ISDBT_SOUND_BROADCASTING is '1'.DTV_ISDBT_SB_SEGMENT_COUNT gives the total count of connected ISDB-Tsb
channels.Possible values: 1 .. 13Note: This value cannot be determined by an automatic channel search.DTV-ISDBT-LAYER* parametersISDB-T channels can be coded hierarchically. As opposed to DVB-T in
ISDB-T hierarchical layers can be decoded simultaneously. For that
reason a ISDB-T demodulator has 3 viterbi and 3 reed-solomon-decoders.ISDB-T has 3 hierarchical layers which each can use a part of the
available segments. The total number of segments over all layers has
to 13 in ISDB-T.There are 3 parameter sets, for Layers A, B and C.DTV_ISDBT_LAYER_ENABLEDHierarchical reception in ISDB-T is achieved by enabling or disabling
layers in the decoding process. Setting all bits of
DTV_ISDBT_LAYER_ENABLED to '1' forces all layers (if applicable) to be
demodulated. This is the default.If the channel is in the partial reception mode
(DTV_ISDBT_PARTIAL_RECEPTION = 1) the central segment can be decoded
independently of the other 12 segments. In that mode layer A has to
have a SEGMENT_COUNT of 1.In ISDB-Tsb only layer A is used, it can be 1 or 3 in ISDB-Tsb
according to DTV_ISDBT_PARTIAL_RECEPTION. SEGMENT_COUNT must be filled
accordingly.Possible values: 0x1, 0x2, 0x4 (|-able)DTV_ISDBT_LAYER_ENABLED[0:0] - layer ADTV_ISDBT_LAYER_ENABLED[1:1] - layer BDTV_ISDBT_LAYER_ENABLED[2:2] - layer CDTV_ISDBT_LAYER_ENABLED[31:3] unusedDTV_ISDBT_LAYER*_FECPossible values: FEC_AUTO, FEC_1_2, FEC_2_3, FEC_3_4, FEC_5_6, FEC_7_8DTV_ISDBT_LAYER*_MODULATIONPossible values: QAM_AUTO, QPSK, QAM_16, QAM_64, DQPSKNote: If layer C is DQPSK layer B has to be DQPSK. If layer B is DQPSK
and DTV_ISDBT_PARTIAL_RECEPTION=0 layer has to be DQPSK.DTV_ISDBT_LAYER*_SEGMENT_COUNTPossible values: 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, -1 (AUTO)Note: Truth table for DTV_ISDBT_SOUND_BROADCASTING and
DTV_ISDBT_PARTIAL_RECEPTION and LAYER*_SEGMENT_COUNTPRSBLayer A widthLayer B widthLayer C widthtotal width001 .. 131 .. 131 .. 13131011 .. 131 .. 13130110011112013DTV_ISDBT_LAYER*_TIME_INTERLEAVINGPossible values: 0, 1, 2, 3, -1 (AUTO)Note: The real inter-leaver depth-names depend on the mode (fft-size); the values
here are referring to what can be found in the TMCC-structure -
independent of the mode.DTV_API_VERSIONReturns the major/minor version of the DVB APIDTV_CODE_RATE_HPUsed on terrestrial transmissions. The acceptable values are:
typedef enum fe_code_rate {
FEC_NONE = 0,
FEC_1_2,
FEC_2_3,
FEC_3_4,
FEC_4_5,
FEC_5_6,
FEC_6_7,
FEC_7_8,
FEC_8_9,
FEC_AUTO,
FEC_3_5,
FEC_9_10,
} fe_code_rate_t;
DTV_CODE_RATE_LPUsed on terrestrial transmissions. The acceptable values are:
typedef enum fe_code_rate {
FEC_NONE = 0,
FEC_1_2,
FEC_2_3,
FEC_3_4,
FEC_4_5,
FEC_5_6,
FEC_6_7,
FEC_7_8,
FEC_8_9,
FEC_AUTO,
FEC_3_5,
FEC_9_10,
} fe_code_rate_t;
DTV_GUARD_INTERVALPossible values are:
typedef enum fe_guard_interval {
GUARD_INTERVAL_1_32,
GUARD_INTERVAL_1_16,
GUARD_INTERVAL_1_8,
GUARD_INTERVAL_1_4,
GUARD_INTERVAL_AUTO,
GUARD_INTERVAL_1_128,
GUARD_INTERVAL_19_128,
GUARD_INTERVAL_19_256,
} fe_guard_interval_t;
Notes:1) If DTV_GUARD_INTERVAL is set the GUARD_INTERVAL_AUTO the hardware will
try to find the correct guard interval (if capable) and will use TMCC to fill
in the missing parameters.2) Intervals 1/128, 19/128 and 19/256 are used only for DVB-T2 at presentDTV_TRANSMISSION_MODESpecifies the number of carriers used by the standardPossible values are:
typedef enum fe_transmit_mode {
TRANSMISSION_MODE_2K,
TRANSMISSION_MODE_8K,
TRANSMISSION_MODE_AUTO,
TRANSMISSION_MODE_4K,
TRANSMISSION_MODE_1K,
TRANSMISSION_MODE_16K,
TRANSMISSION_MODE_32K,
} fe_transmit_mode_t;
Notes:1) ISDB-T supports three carrier/symbol-size: 8K, 4K, 2K. It is called
'mode' in the standard: Mode 1 is 2K, mode 2 is 4K, mode 3 is 8K2) If DTV_TRANSMISSION_MODE is set the TRANSMISSION_MODE_AUTO the
hardware will try to find the correct FFT-size (if capable) and will
use TMCC to fill in the missing parameters.3) DVB-T specifies 2K and 8K as valid sizes.4) DVB-T2 specifies 1K, 2K, 4K, 8K, 16K and 32K.DTV_HIERARCHYFrontend hierarchy
typedef enum fe_hierarchy {
HIERARCHY_NONE,
HIERARCHY_1,
HIERARCHY_2,
HIERARCHY_4,
HIERARCHY_AUTO
} fe_hierarchy_t;
DTV_ISDBS_TS_IDCurrently unused.DTV_DVBT2_PLP_IDDVB-T2 supports Physical Layer Pipes (PLP) to allow transmission of
many data types via a single multiplex. The API will soon support this
at which point this section will be expanded.Properties used on terrestrial delivery systemsDVB-T delivery systemThe following parameters are valid for DVB-T:DTV_API_VERSIONDTV_DELIVERY_SYSTEMDTV_TUNEDTV_CLEARDTV_FREQUENCYDTV_MODULATIONDTV_BANDWIDTH_HZDTV_INVERSIONDTV_CODE_RATE_HPDTV_CODE_RATE_LPDTV_GUARD_INTERVALDTV_TRANSMISSION_MODEDTV_HIERARCHYDVB-T2 delivery systemDVB-T2 support is currently in the early stages
of development, so expect that this section maygrow and become
more detailed with time.The following parameters are valid for DVB-T2:DTV_API_VERSIONDTV_DELIVERY_SYSTEMDTV_TUNEDTV_CLEARDTV_FREQUENCYDTV_MODULATIONDTV_BANDWIDTH_HZDTV_INVERSIONDTV_CODE_RATE_HPDTV_CODE_RATE_LPDTV_GUARD_INTERVALDTV_TRANSMISSION_MODEDTV_HIERARCHYDTV_DVBT2_PLP_IDISDB-T delivery systemThis ISDB-T/ISDB-Tsb API extension should reflect all information
needed to tune any ISDB-T/ISDB-Tsb hardware. Of course it is possible
that some very sophisticated devices won't need certain parameters to
tune.The information given here should help application writers to know how
to handle ISDB-T and ISDB-Tsb hardware using the Linux DVB-API.The details given here about ISDB-T and ISDB-Tsb are just enough to
basically show the dependencies between the needed parameter values,
but surely some information is left out. For more detailed information
see the following documents:ARIB STD-B31 - "Transmission System for Digital Terrestrial
Television Broadcasting" andARIB TR-B14 - "Operational Guidelines for Digital Terrestrial
Television Broadcasting".In order to understand the ISDB specific parameters,
one has to have some knowledge the channel structure in
ISDB-T and ISDB-Tsb. I.e. it has to be known to
the reader that an ISDB-T channel consists of 13 segments,
that it can have up to 3 layer sharing those segments,
and things like that.The following parameters are valid for ISDB-T:DTV_API_VERSIONDTV_DELIVERY_SYSTEMDTV_TUNEDTV_CLEARDTV_FREQUENCYDTV_MODULATIONDTV_BANDWIDTH_HZDTV_INVERSIONDTV_CODE_RATE_HPDTV_CODE_RATE_LPDTV_GUARD_INTERVALDTV_TRANSMISSION_MODEDTV_HIERARCHYDTV_ISDBT_LAYER_ENABLEDDTV_ISDBT_PARTIAL_RECEPTIONDTV_ISDBT_SOUND_BROADCASTINGDTV_ISDBT_SB_SUBCHANNEL_IDDTV_ISDBT_SB_SEGMENT_IDXDTV_ISDBT_SB_SEGMENT_COUNTDTV_ISDBT_LAYERA_FECDTV_ISDBT_LAYERA_MODULATIONDTV_ISDBT_LAYERA_SEGMENT_COUNTDTV_ISDBT_LAYERA_TIME_INTERLEAVINGDTV_ISDBT_LAYERB_FECDTV_ISDBT_LAYERB_MODULATIONDTV_ISDBT_LAYERB_SEGMENT_COUNTDTV_ISDBT_LAYERB_TIME_INTERLEAVINGDTV_ISDBT_LAYERC_FECDTV_ISDBT_LAYERC_MODULATIONDTV_ISDBT_LAYERC_SEGMENT_COUNTDTV_ISDBT_LAYERC_TIME_INTERLEAVINGATSC delivery systemThe following parameters are valid for ATSC:DTV_API_VERSIONDTV_DELIVERY_SYSTEMDTV_TUNEDTV_CLEARDTV_FREQUENCYDTV_MODULATIONDTV_BANDWIDTH_HZProperties used on cable delivery systemsDVB-C delivery systemThe DVB-C Annex-A/C is the widely used cable standard. Transmission uses QAM modulation.The following parameters are valid for DVB-C Annex A/C:DTV_API_VERSIONDTV_DELIVERY_SYSTEMDTV_TUNEDTV_CLEARDTV_FREQUENCYDTV_MODULATIONDTV_INVERSIONDTV_SYMBOL_RATEDTV_INNER_FECDVB-C Annex B delivery systemThe DVB-C Annex-B is only used on a few Countries like the United States.The following parameters are valid for DVB-C Annex B:DTV_API_VERSIONDTV_DELIVERY_SYSTEMDTV_TUNEDTV_CLEARDTV_FREQUENCYDTV_MODULATIONDTV_INVERSIONProperties used on satellital delivery systemsDVB-S delivery systemThe following parameters are valid for DVB-S:DTV_API_VERSIONDTV_DELIVERY_SYSTEMDTV_TUNEDTV_CLEARDTV_FREQUENCYDTV_INVERSIONDTV_SYMBOL_RATEDTV_INNER_FECFuture implementations might add those two missing parameters:DTV_DISEQC_MASTERDTV_DISEQC_SLAVE_REPLYDVB-S2 delivery systemThe following parameters are valid for DVB-S2:DTV_API_VERSIONDTV_DELIVERY_SYSTEMDTV_TUNEDTV_CLEARDTV_FREQUENCYDTV_INVERSIONDTV_SYMBOL_RATEDTV_INNER_FECDTV_VOLTAGEDTV_TONEDTV_PILOTDTV_ROLLOFFFuture implementations might add those two missing parameters:DTV_DISEQC_MASTERDTV_DISEQC_SLAVE_REPLYISDB-S delivery systemThe following parameters are valid for ISDB-S:DTV_API_VERSIONDTV_DELIVERY_SYSTEMDTV_TUNEDTV_CLEARDTV_FREQUENCYDTV_INVERSIONDTV_SYMBOL_RATEDTV_INNER_FECDTV_VOLTAGEDTV_ISDBS_TS_ID