path: root/Documentation/DocBook/dvb/dvbproperty.xml

<section id="FE_GET_SET_PROPERTY">
<title>FE_GET_PROPERTY/FE_SET_PROPERTY</title>

<programlisting>
/* 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

struct dtv_properties {
	__u32 num;
	struct dtv_property *props;
};
</programlisting>

<section id="FE_GET_PROPERTY">
<title>FE_GET_PROPERTY</title>
<para>DESCRIPTION
</para>
<informaltable><tgroup cols="1"><tbody><row><entry
 align="char">
<para>This ioctl call returns one or more frontend properties. This call only
 requires read-only access to the device.</para>
</entry>
 </row></tbody></tgroup></informaltable>
<para>SYNOPSIS
</para>
<informaltable><tgroup cols="1"><tbody><row><entry
 align="char">
<para>int ioctl(int fd, int request = <link linkend="FE_GET_PROPERTY">FE_GET_PROPERTY</link>,
 dtv_properties &#x22C6;props);</para>
</entry>
 </row></tbody></tgroup></informaltable>
<para>PARAMETERS
</para>
<informaltable><tgroup cols="2"><tbody><row><entry align="char">
<para>int fd</para>
</entry><entry
 align="char">
<para>File descriptor returned by a previous call to open().</para>
</entry>
 </row><row><entry
 align="char">
<para>int num</para>
</entry><entry
 align="char">
<para>Equals <link linkend="FE_GET_PROPERTY">FE_GET_PROPERTY</link> for this command.</para>
</entry>
 </row><row><entry
 align="char">
<para>struct dtv_property *props</para>
</entry><entry
 align="char">
<para>Points to the location where the front-end property commands are stored.</para>
</entry>
 </row></tbody></tgroup></informaltable>
<para>ERRORS</para>
<informaltable><tgroup cols="2"><tbody><row>
  <entry align="char"><para>EINVAL</para></entry>
  <entry align="char"><para>Invalid parameter(s) received or number of parameters out of the range.</para></entry>
 </row><row>
  <entry align="char"><para>ENOMEM</para></entry>
  <entry align="char"><para>Out of memory.</para></entry>
 </row><row>
  <entry align="char"><para>EFAULT</para></entry>
  <entry align="char"><para>Failure while copying data from/to userspace.</para></entry>
 </row><row>
  <entry align="char"><para>EOPNOTSUPP</para></entry>
  <entry align="char"><para>Property type not supported.</para></entry>
 </row></tbody></tgroup></informaltable>
</section>

<section id="FE_SET_PROPERTY">
<title>FE_SET_PROPERTY</title>
<para>DESCRIPTION
</para>
<informaltable><tgroup cols="1"><tbody><row><entry
 align="char">
<para>This ioctl call sets one or more frontend properties. This call only
 requires read-only access to the device.</para>
</entry>
 </row></tbody></tgroup></informaltable>
<para>SYNOPSIS
</para>
<informaltable><tgroup cols="1"><tbody><row><entry
 align="char">
<para>int ioctl(int fd, int request = <link linkend="FE_SET_PROPERTY">FE_SET_PROPERTY</link>,
 dtv_properties &#x22C6;props);</para>
</entry>
 </row></tbody></tgroup></informaltable>
<para>PARAMETERS
</para>
<informaltable><tgroup cols="2"><tbody><row><entry align="char">
<para>int fd</para>
</entry><entry
 align="char">
<para>File descriptor returned by a previous call to open().</para>
</entry>
 </row><row><entry
 align="char">
<para>int num</para>
</entry><entry
 align="char">
<para>Equals <link linkend="FE_SET_PROPERTY">FE_SET_PROPERTY</link> for this command.</para>
</entry>
 </row><row><entry
 align="char">
<para>struct dtv_property *props</para>
</entry><entry
 align="char">
<para>Points to the location where the front-end property commands are stored.</para>
</entry>
 </row></tbody></tgroup></informaltable>
<para>ERRORS
</para>
<informaltable><tgroup cols="2"><tbody><row>
  <entry align="char"><para>EINVAL</para></entry>
  <entry align="char"><para>Invalid parameter(s) received or number of parameters out of the range.</para></entry>
 </row><row>
  <entry align="char"><para>ENOMEM</para></entry>
  <entry align="char"><para>Out of memory.</para></entry>
 </row><row>
  <entry align="char"><para>EFAULT</para></entry>
  <entry align="char"><para>Failure while copying data from/to userspace.</para></entry>
 </row><row>
  <entry align="char"><para>EOPNOTSUPP</para></entry>
  <entry align="char"><para>Property type not supported.</para></entry>
 </row></tbody></tgroup></informaltable>
</section>

<para>
On <link linkend="FE_GET_PROPERTY">FE_GET_PROPERTY</link>/<link linkend="FE_SET_PROPERTY">FE_SET_PROPERTY</link>,
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.
</para>

<para>The Available frontend property types are:</para>
<programlisting>
#define DTV_UNDEFINED		0
#define DTV_TUNE		1
#define DTV_CLEAR		2
#define DTV_FREQUENCY		3
#define DTV_MODULATION		4
#define DTV_BANDWIDTH_HZ	5
#define DTV_INVERSION		6
#define DTV_DISEQC_MASTER	7
#define DTV_SYMBOL_RATE		8
#define DTV_INNER_FEC		9
#define DTV_VOLTAGE		10
#define DTV_TONE		11
#define DTV_PILOT		12
#define DTV_ROLLOFF		13
#define DTV_DISEQC_SLAVE_REPLY	14
#define DTV_FE_CAPABILITY_COUNT	15
#define DTV_FE_CAPABILITY	16
#define DTV_DELIVERY_SYSTEM	17
#define DTV_ISDBT_PARTIAL_RECEPTION	18
#define DTV_ISDBT_SOUND_BROADCASTING	19
#define DTV_ISDBT_SB_SUBCHANNEL_ID	20
#define DTV_ISDBT_SB_SEGMENT_IDX	21
#define DTV_ISDBT_SB_SEGMENT_COUNT	22
#define DTV_ISDBT_LAYERA_FEC			23
#define DTV_ISDBT_LAYERA_MODULATION		24
#define DTV_ISDBT_LAYERA_SEGMENT_COUNT		25
#define DTV_ISDBT_LAYERA_TIME_INTERLEAVING	26
#define DTV_ISDBT_LAYERB_FEC			27
#define DTV_ISDBT_LAYERB_MODULATION		28
#define DTV_ISDBT_LAYERB_SEGMENT_COUNT		29
#define DTV_ISDBT_LAYERB_TIME_INTERLEAVING	30
#define DTV_ISDBT_LAYERC_FEC			31
#define DTV_ISDBT_LAYERC_MODULATION		32
#define DTV_ISDBT_LAYERC_SEGMENT_COUNT		33
#define DTV_ISDBT_LAYERC_TIME_INTERLEAVING	34
#define DTV_API_VERSION		35
#define DTV_CODE_RATE_HP	36
#define DTV_CODE_RATE_LP	37
#define DTV_GUARD_INTERVAL	38
#define DTV_TRANSMISSION_MODE	39
#define DTV_HIERARCHY		40
#define DTV_ISDBT_LAYER_ENABLED	41
#define DTV_ISDBS_TS_ID		42
</programlisting>

<section id="fe_property_common">
	<title>Parameters that are common to all Digital TV standards</title>
	<section id="DTV_FREQUENCY">
		<title><constant>DTV_FREQUENCY</constant></title>

		<para>Central frequency of the channel, in HZ.</para>

		<para>Notes:</para>
		<para>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.</para>

		<para>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.</para>
	</section>

	<section id="DTV_BANDWIDTH_HZ">
		<title><constant>DTV_BANDWIDTH_HZ</constant></title>

		<para>Bandwidth for the channel, in HZ.</para>

		<para>Possible values:
			<constant>6000000</constant>,
			<constant>7000000</constant>,
			<constant>8000000</constant>.
		</para>

		<para>Notes:</para>

		<para>1) For ISDB-T it should be always 6000000Hz (6MHz)</para>
		<para>2) For ISDB-Tsb it can vary depending on the number of connected segments</para>
		<para>3) Bandwidth doesn't apply for DVB-C transmissions, as the bandwidth
			 for DVB-C depends on the symbol rate</para>
		<para>4) 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).</para>
	</section>

	<section id="DTV_DELIVERY_SYSTEM">
		<title><constant>DTV_DELIVERY_SYSTEM</constant></title>

		<para>Specifies the type of Delivery system</para>

		<para>Possible values: </para>
<programlisting>
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,
} fe_delivery_system_t;
</programlisting>

	</section>

	<section id="DTV_TRANSMISSION_MODE">
		<title><constant>DTV_TRANSMISSION_MODE</constant></title>

		<para>Specifies the number of carriers used by the standard</para>

		<para>Possible values are:</para>
<programlisting>
typedef enum fe_transmit_mode {
	TRANSMISSION_MODE_2K,
	TRANSMISSION_MODE_8K,
	TRANSMISSION_MODE_AUTO,
	TRANSMISSION_MODE_4K
} fe_transmit_mode_t;
</programlisting>

		<para>Notes:</para>
		<para>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 8K</para>

		<para>2) If <constant>DTV_TRANSMISSION_MODE</constant> is set the <constant>TRANSMISSION_MODE_AUTO</constant> the
			hardware will try to find the correct FFT-size (if capable) and will
			use TMCC to fill in the missing parameters.</para>
	</section>

	<section id="DTV_GUARD_INTERVAL">
		<title><constant>DTV_GUARD_INTERVAL</constant></title>

		<para>Possible values are:</para>
<programlisting>
typedef enum fe_guard_interval {
	GUARD_INTERVAL_1_32,
	GUARD_INTERVAL_1_16,
	GUARD_INTERVAL_1_8,
	GUARD_INTERVAL_1_4,
	GUARD_INTERVAL_AUTO
} fe_guard_interval_t;
</programlisting>

		<para>Notes:</para>
		<para>1) If <constant>DTV_GUARD_INTERVAL</constant> is set the <constant>GUARD_INTERVAL_AUTO</constant> the hardware will
			try to find the correct guard interval (if capable) and will use TMCC to fill
			in the missing parameters.</para>
	</section>
</section>

<section id="isdbt">
	<title>ISDB-T frontend</title>
	<para>This section describes shortly what are the possible parameters in the Linux
		DVB-API called "S2API" and now DVB API 5 in order to tune an ISDB-T/ISDB-Tsb
		demodulator:</para>

	<para>This 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.</para>

	<para>The information given here should help application writers to know how
		to handle ISDB-T and ISDB-Tsb hardware using the Linux DVB-API.</para>

	<para>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:</para>

	<para>ARIB STD-B31 - "Transmission System for Digital Terrestrial
		Television Broadcasting" and</para>
	<para>ARIB TR-B14 - "Operational Guidelines for Digital Terrestrial
		Television Broadcasting".</para>

	<para>In order to read this document 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.</para>

	<para>Parameters used by ISDB-T and ISDB-Tsb.</para>

	<section id="isdbt-new-parms">
		<title>ISDB-T only parameters</title>

		<section id="isdbt-part-rec">
			<title><constant>DTV_ISDBT_PARTIAL_RECEPTION</constant></title>

			<para><constant>If DTV_ISDBT_SOUND_BROADCASTING</constant> is '0' this bit-field represents whether
				the channel is in partial reception mode or not.</para>

			<para>If '1' <constant>DTV_ISDBT_LAYERA_*</constant> values are assigned to the center segment and
				<constant>DTV_ISDBT_LAYERA_SEGMENT_COUNT</constant> has to be '1'.</para>

			<para>If in addition <constant>DTV_ISDBT_SOUND_BROADCASTING</constant> is '1'
				<constant>DTV_ISDBT_PARTIAL_RECEPTION</constant> represents whether this ISDB-Tsb channel
				is consisting of one segment and layer or three segments and two layers.</para>

			<para>Possible values: 0, 1, -1 (AUTO)</para>
		</section>

		<section id="isdbt-sound-bcast">
			<title><constant>DTV_ISDBT_SOUND_BROADCASTING</constant></title>

			<para>This field represents whether the other DTV_ISDBT_*-parameters are
				referring to an ISDB-T and an ISDB-Tsb channel. (See also
				<constant>DTV_ISDBT_PARTIAL_RECEPTION</constant>).</para>

			<para>Possible values: 0, 1, -1 (AUTO)</para>
		</section>

		<section id="isdbt-sb-ch-id">
			<title><constant>DTV_ISDBT_SB_SUBCHANNEL_ID</constant></title>

			<para>This field only applies if <constant>DTV_ISDBT_SOUND_BROADCASTING</constant> is '1'.</para>

			<para>(Note of the author: This might not be the correct description of the
				<constant>SUBCHANNEL-ID</constant> in all details, but it is my understanding of the technical
				background needed to program a device)</para>

			<para>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.</para>

			<para>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.</para>

			<para>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.</para>

			<para>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.</para>

			<para><constant>The DTV_ISDBT_SB_SUBCHANNEL_ID</constant> parameter is used to give the
				sub-channel ID of the segment to be demodulated.</para>

			<para>Possible values: 0 .. 41, -1 (AUTO)</para>
		</section>

		<section id="isdbt-sb-seg-idx">

			<title><constant>DTV_ISDBT_SB_SEGMENT_IDX</constant></title>

			<para>This field only applies if <constant>DTV_ISDBT_SOUND_BROADCASTING</constant> is '1'.</para>

			<para><constant>DTV_ISDBT_SB_SEGMENT_IDX</constant> gives the index of the segment to be
				demodulated for an ISDB-Tsb channel where several of them are
				transmitted in the connected manner.</para>

			<para>Possible values: 0 .. <constant>DTV_ISDBT_SB_SEGMENT_COUNT</constant> - 1</para>

			<para>Note: This value cannot be determined by an automatic channel search.</para>
		</section>

		<section id="isdbt-sb-seg-cnt">
			<title><constant>DTV_ISDBT_SB_SEGMENT_COUNT</constant></title>

			<para>This field only applies if <constant>DTV_ISDBT_SOUND_BROADCASTING</constant> is '1'.</para>

			<para><constant>DTV_ISDBT_SB_SEGMENT_COUNT</constant> gives the total count of connected ISDB-Tsb
				channels.</para>

			<para>Possible values: 1 .. 13</para>

			<para>Note: This value cannot be determined by an automatic channel search.</para>
		</section>

		<section id="isdb-hierq-layers">
			<title>Hierarchical layers</title>

			<para>ISDB-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.</para>

			<para>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.</para>

			<section id="isdbt-layer-ena">
				<title><constant>DTV_ISDBT_LAYER_ENABLED</constant></title>

				<para>Hierarchical reception in ISDB-T is achieved by enabling or disabling
					layers in the decoding process. Setting all bits of
					<constant>DTV_ISDBT_LAYER_ENABLED</constant> to '1' forces all layers (if applicable) to be
					demodulated. This is the default.</para>

				<para>If the channel is in the partial reception mode
					(<constant>DTV_ISDBT_PARTIAL_RECEPTION</constant> = 1) the central segment can be decoded
					independently of the other 12 segments. In that mode layer A has to
					have a <constant>SEGMENT_COUNT</constant> of 1.</para>

				<para>In ISDB-Tsb only layer A is used, it can be 1 or 3 in ISDB-Tsb
					according to <constant>DTV_ISDBT_PARTIAL_RECEPTION</constant>. <constant>SEGMENT_COUNT</constant> must be filled
					accordingly.</para>

				<para>Possible values: 0x1, 0x2, 0x4 (|-able)</para>

				<para><constant>DTV_ISDBT_LAYER_ENABLED[0:0]</constant> - layer A</para>
				<para><constant>DTV_ISDBT_LAYER_ENABLED[1:1]</constant> - layer B</para>
				<para><constant>DTV_ISDBT_LAYER_ENABLED[2:2]</constant> - layer C</para>
				<para><constant>DTV_ISDBT_LAYER_ENABLED[31:3]</constant> unused</para>
			</section>

			<section id="isdbt-layer-fec">
				<title><constant>DTV_ISDBT_LAYER*_FEC</constant></title>

				<para>Possible values: <constant>FEC_AUTO</constant>, <constant>FEC_1_2</constant>, <constant>FEC_2_3</constant>, <constant>FEC_3_4</constant>, <constant>FEC_5_6</constant>, <constant>FEC_7_8</constant></para>
			</section>

			<section id="isdbt-layer-mod">
				<title><constant>DTV_ISDBT_LAYER*_MODULATION</constant></title>

				<para>Possible values: <constant>QAM_AUTO</constant>, QP<constant>SK, QAM_16</constant>, <constant>QAM_64</constant>, <constant>DQPSK</constant></para>

				<para>Note: If layer C is <constant>DQPSK</constant> layer B has to be <constant>DQPSK</constant>. If layer B is <constant>DQPSK</constant>
					and <constant>DTV_ISDBT_PARTIAL_RECEPTION</constant>=0 layer has to be <constant>DQPSK</constant>.</para>
			</section>

			<section id="isdbt-layer-seg-cnt">
				<title><constant>DTV_ISDBT_LAYER*_SEGMENT_COUNT</constant></title>

				<para>Possible values: 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, -1 (AUTO)</para>

				<para>Note: Truth table for <constant>DTV_ISDBT_SOUND_BROADCASTING</constant> and
					<constant>DTV_ISDBT_PARTIAL_RECEPTION</constant> and <constant>LAYER</constant>*_SEGMENT_COUNT</para>

				<informaltable id="isdbt-layer_seg-cnt-table">
					<tgroup cols="6">

						<tbody>
							<row>
								<entry>PR</entry>
								<entry>SB</entry>
								<entry>Layer A width</entry>
								<entry>Layer B width</entry>
								<entry>Layer C width</entry>
								<entry>total width</entry>
							</row>

							<row>
								<entry>0</entry>
								<entry>0</entry>
								<entry>1 .. 13</entry>
								<entry>1 .. 13</entry>
								<entry>1 .. 13</entry>
								<entry>13</entry>
							</row>

							<row>
								<entry>1</entry>
								<entry>0</entry>
								<entry>1</entry>
								<entry>1 .. 13</entry>
								<entry>1 .. 13</entry>
								<entry>13</entry>
							</row>

							<row>
								<entry>0</entry>
								<entry>1</entry>
								<entry>1</entry>
								<entry>0</entry>
								<entry>0</entry>
								<entry>1</entry>
							</row>

							<row>
								<entry>1</entry>
								<entry>1</entry>
								<entry>1</entry>
								<entry>2</entry>
								<entry>0</entry>
								<entry>13</entry>
							</row>
						</tbody>

					</tgroup>
				</informaltable>

			</section>

			<section id="isdbt_layer_t_interl">
				<title><constant>DTV_ISDBT_LAYER*_TIME_INTERLEAVING</constant></title>

				<para>Possible values: 0, 1, 2, 3, -1 (AUTO)</para>

				<para>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.</para>
			</section>
		</section>
	</section>
</section>
</section>