doc/spec/r9288.htm

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>Video for Linux Two API Specification: Revision 0.24</TH
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><H1
><A
NAME="VIDIOC-ENUMSTD"
></A
>ioctl VIDIOC_ENUMSTD</H1
><DIV
CLASS="REFNAMEDIV"
><A
NAME="AEN9292"
></A
><H2
>Name</H2
>VIDIOC_ENUMSTD&nbsp;--&nbsp;Enumerate supported video standards</DIV
><DIV
CLASS="REFSYNOPSISDIV"
><A
NAME="AEN9295"
></A
><H2
>Synopsis</H2
><DIV
CLASS="FUNCSYNOPSIS"
><P
></P
><A
NAME="AEN9296"
></A
><P
><CODE
><CODE
CLASS="FUNCDEF"
>int ioctl</CODE
>(int fd, int request, struct v4l2_standard *argp);</CODE
></P
><P
></P
></DIV
></DIV
><DIV
CLASS="REFSECT1"
><A
NAME="AEN9306"
></A
><H2
>Arguments</H2
><P
></P
><DIV
CLASS="VARIABLELIST"
><DL
><DT
><CODE
CLASS="PARAMETER"
>fd</CODE
></DT
><DD
><P
>File descriptor returned by <A
HREF="r14090.htm"
><CODE
CLASS="FUNCTION"
>open()</CODE
></A
>.</P
></DD
><DT
><CODE
CLASS="PARAMETER"
>request</CODE
></DT
><DD
><P
>VIDIOC_ENUMSTD</P
></DD
><DT
><CODE
CLASS="PARAMETER"
>argp</CODE
></DT
><DD
><P
></P
></DD
></DL
></DIV
></DIV
><DIV
CLASS="REFSECT1"
><A
NAME="AEN9326"
></A
><H2
>Description</H2
><P
>To query the attributes of a video standard,
especially a custom (driver defined) one, applications initialize the
<CODE
CLASS="STRUCTFIELD"
>index</CODE
> field of struct&nbsp;<A
HREF="r9288.htm#V4L2-STANDARD"
>v4l2_standard</A
> and call the
<CODE
CLASS="CONSTANT"
>VIDIOC_ENUMSTD</CODE
> ioctl with a pointer to this
structure. Drivers fill the rest of the structure or return an
<SPAN
CLASS="ERRORCODE"
>EINVAL</SPAN
> error code when the index is out of bounds. To enumerate all standards
applications shall begin  at index zero, incrementing by one until the
driver returns <SPAN
CLASS="ERRORCODE"
>EINVAL</SPAN
>. Drivers may enumerate a
different set of standards after switching the video input or
output.<A
NAME="AEN9334"
HREF="r9288.htm#FTN.AEN9334"
><SPAN
CLASS="footnote"
>[1]</SPAN
></A
></P
><DIV
CLASS="TABLE"
><A
NAME="V4L2-STANDARD"
></A
><P
><B
>Table 1. struct <CODE
CLASS="STRUCTNAME"
>v4l2_standard</CODE
></B
></P
><TABLE
BORDER="0"
FRAME="void"
WIDTH="100%"
CLASS="CALSTABLE"
><COL
WIDTH="25%"
TITLE="C1"><COL
WIDTH="25%"
TITLE="C2"><COL
WIDTH="50%"
TITLE="C3"><TBODY
VALIGN="TOP"
><TR
><TD
>__u32</TD
><TD
><CODE
CLASS="STRUCTFIELD"
>index</CODE
></TD
><TD
>Number of the video standard, set by the
application.</TD
></TR
><TR
><TD
><A
HREF="r9288.htm#V4L2-STD-ID"
>v4l2_std_id</A
></TD
><TD
><CODE
CLASS="STRUCTFIELD"
>id</CODE
></TD
><TD
>The bits in this field identify the standard as
one of the common standards listed in <A
HREF="r9288.htm#V4L2-STD-ID"
>Table 3</A
>,
or if bits 32 to 63 are set as custom standards. Multiple bits can be
set if the hardware does not distinguish between these standards,
however separate indices do not indicate the opposite. The
<CODE
CLASS="STRUCTFIELD"
>id</CODE
> must be unique. No other enumerated
<CODE
CLASS="STRUCTNAME"
>v4l2_standard</CODE
> structure, for this input or
output anyway, can contain the same set of bits.</TD
></TR
><TR
><TD
>__u8</TD
><TD
><CODE
CLASS="STRUCTFIELD"
>name</CODE
>[24]</TD
><TD
>Name of the standard, a NUL-terminated ASCII
string, for example: "PAL-B/G", "NTSC Japan". This information is
intended for the user.</TD
></TR
><TR
><TD
>struct&nbsp;<A
HREF="r9288.htm#V4L2-FRACT"
>v4l2_fract</A
></TD
><TD
><CODE
CLASS="STRUCTFIELD"
>frameperiod</CODE
></TD
><TD
>The frame period (not field period) is numerator
/ denominator. For example M/NTSC has a frame period of 1001 /
30000 seconds.</TD
></TR
><TR
><TD
>__u32</TD
><TD
><CODE
CLASS="STRUCTFIELD"
>framelines</CODE
></TD
><TD
>Total lines per frame including blanking,
e.&nbsp;g. 625 for B/PAL.</TD
></TR
><TR
><TD
>__u32</TD
><TD
><CODE
CLASS="STRUCTFIELD"
>reserved</CODE
>[4]</TD
><TD
>Reserved for future extensions. Drivers must set
the array to zero.</TD
></TR
></TBODY
></TABLE
></DIV
><DIV
CLASS="TABLE"
><A
NAME="V4L2-FRACT"
></A
><P
><B
>Table 2. struct <CODE
CLASS="STRUCTNAME"
>v4l2_fract</CODE
></B
></P
><TABLE
BORDER="0"
FRAME="void"
WIDTH="100%"
CLASS="CALSTABLE"
><COL
WIDTH="25%"
TITLE="C1"><COL
WIDTH="25%"
TITLE="C2"><COL
WIDTH="50%"
TITLE="C3"><TBODY
VALIGN="TOP"
><TR
><TD
>__u32</TD
><TD
><CODE
CLASS="STRUCTFIELD"
>numerator</CODE
></TD
><TD
>&nbsp;</TD
></TR
><TR
><TD
>__u32</TD
><TD
><CODE
CLASS="STRUCTFIELD"
>denominator</CODE
></TD
><TD
>&nbsp;</TD
></TR
></TBODY
></TABLE
></DIV
><DIV
CLASS="TABLE"
><A
NAME="V4L2-STD-ID"
></A
><P
><B
>Table 3. typedef <CODE
CLASS="STRUCTNAME"
>v4l2_std_id</CODE
></B
></P
><TABLE
BORDER="0"
FRAME="void"
WIDTH="100%"
CLASS="CALSTABLE"
><COL
WIDTH="25%"
TITLE="C1"><COL
WIDTH="25%"
TITLE="C2"><COL
WIDTH="50%"
TITLE="C3"><TBODY
VALIGN="TOP"
><TR
><TD
>__u64</TD
><TD
><CODE
CLASS="STRUCTFIELD"
>v4l2_std_id</CODE
></TD
><TD
>This type is a set, each bit representing another
video standard as listed below and in <A
HREF="r9288.htm#VIDEO-STANDARDS"
>Table 4</A
>. The 32 most significant bits are reserved
for custom (driver defined) video standards.</TD
></TR
></TBODY
></TABLE
></DIV
><P
><PRE
CLASS="PROGRAMLISTING"
>#define V4L2_STD_PAL_B          ((v4l2_std_id)0x00000001)
#define V4L2_STD_PAL_B1         ((v4l2_std_id)0x00000002)
#define V4L2_STD_PAL_G          ((v4l2_std_id)0x00000004)
#define V4L2_STD_PAL_H          ((v4l2_std_id)0x00000008)
#define V4L2_STD_PAL_I          ((v4l2_std_id)0x00000010)
#define V4L2_STD_PAL_D          ((v4l2_std_id)0x00000020)
#define V4L2_STD_PAL_D1         ((v4l2_std_id)0x00000040)
#define V4L2_STD_PAL_K          ((v4l2_std_id)0x00000080)

#define V4L2_STD_PAL_M          ((v4l2_std_id)0x00000100)
#define V4L2_STD_PAL_N          ((v4l2_std_id)0x00000200)
#define V4L2_STD_PAL_Nc         ((v4l2_std_id)0x00000400)
#define V4L2_STD_PAL_60         ((v4l2_std_id)0x00000800)</PRE
></P
><P
><CODE
CLASS="CONSTANT"
>V4L2_STD_PAL_60</CODE
> is
a hybrid standard with 525 lines, 60 Hz refresh rate, and PAL color
modulation with a 4.43 MHz color subcarrier. Some PAL video recorders
can play back NTSC tapes in this mode for display on a 50/60 Hz agnostic
PAL TV.</P
><P
><PRE
CLASS="PROGRAMLISTING"
>#define V4L2_STD_NTSC_M         ((v4l2_std_id)0x00001000)
#define V4L2_STD_NTSC_M_JP      ((v4l2_std_id)0x00002000)
#define V4L2_STD_NTSC_443       ((v4l2_std_id)0x00004000)</PRE
></P
><P
><CODE
CLASS="CONSTANT"
>V4L2_STD_NTSC_443</CODE
>
is a hybrid standard with 525 lines, 60 Hz refresh rate, and NTSC
color modulation with a 4.43 MHz color
subcarrier.</P
><P
><PRE
CLASS="PROGRAMLISTING"
>#define V4L2_STD_NTSC_M_KR      ((v4l2_std_id)0x00008000)

#define V4L2_STD_SECAM_B        ((v4l2_std_id)0x00010000)
#define V4L2_STD_SECAM_D        ((v4l2_std_id)0x00020000)
#define V4L2_STD_SECAM_G        ((v4l2_std_id)0x00040000)
#define V4L2_STD_SECAM_H        ((v4l2_std_id)0x00080000)
#define V4L2_STD_SECAM_K        ((v4l2_std_id)0x00100000)
#define V4L2_STD_SECAM_K1       ((v4l2_std_id)0x00200000)
#define V4L2_STD_SECAM_L        ((v4l2_std_id)0x00400000)
#define V4L2_STD_SECAM_LC       ((v4l2_std_id)0x00800000)

/* ATSC/HDTV */
#define V4L2_STD_ATSC_8_VSB     ((v4l2_std_id)0x01000000)
#define V4L2_STD_ATSC_16_VSB    ((v4l2_std_id)0x02000000)</PRE
></P
><P
><CODE
CLASS="CONSTANT"
>V4L2_STD_ATSC_8_VSB</CODE
> and
<CODE
CLASS="CONSTANT"
>V4L2_STD_ATSC_16_VSB</CODE
> are U.S. terrestrial digital
TV standards. Presently the V4L2 API does not support digital TV. See
also the Linux DVB API at <A
HREF="http://linuxtv.org"
TARGET="_top"
>http://linuxtv.org</A
>.</P
><P
><PRE
CLASS="PROGRAMLISTING"
>#define V4L2_STD_PAL_BG         (V4L2_STD_PAL_B         |\
                                 V4L2_STD_PAL_B1        |\
                                 V4L2_STD_PAL_G)
#define V4L2_STD_B              (V4L2_STD_PAL_B         |\
                                 V4L2_STD_PAL_B1        |\
                                 V4L2_STD_SECAM_B)
#define V4L2_STD_GH             (V4L2_STD_PAL_G         |\
                                 V4L2_STD_PAL_H         |\
                                 V4L2_STD_SECAM_G       |\
                                 V4L2_STD_SECAM_H)
#define V4L2_STD_PAL_DK         (V4L2_STD_PAL_D         |\
                                 V4L2_STD_PAL_D1        |\
                                 V4L2_STD_PAL_K)
#define V4L2_STD_PAL            (V4L2_STD_PAL_BG        |\
                                 V4L2_STD_PAL_DK        |\
                                 V4L2_STD_PAL_H         |\
                                 V4L2_STD_PAL_I)
#define V4L2_STD_NTSC           (V4L2_STD_NTSC_M        |\
                                 V4L2_STD_NTSC_M_JP     |\
                                 V4L2_STD_NTSC_M_KR)
#define V4L2_STD_MN             (V4L2_STD_PAL_M         |\
                                 V4L2_STD_PAL_N         |\
                                 V4L2_STD_PAL_Nc        |\
                                 V4L2_STD_NTSC)
#define V4L2_STD_SECAM_DK       (V4L2_STD_SECAM_D       |\
                                 V4L2_STD_SECAM_K       |\
                                 V4L2_STD_SECAM_K1)
#define V4L2_STD_DK             (V4L2_STD_PAL_DK        |\
                                 V4L2_STD_SECAM_DK)

#define V4L2_STD_SECAM          (V4L2_STD_SECAM_B       |\
                                 V4L2_STD_SECAM_G       |\
                                 V4L2_STD_SECAM_H       |\
                                 V4L2_STD_SECAM_DK      |\
                                 V4L2_STD_SECAM_L       |\
                                 V4L2_STD_SECAM_LC)

#define V4L2_STD_525_60         (V4L2_STD_PAL_M         |\
                                 V4L2_STD_PAL_60        |\
                                 V4L2_STD_NTSC          |\
                                 V4L2_STD_NTSC_443)
#define V4L2_STD_625_50         (V4L2_STD_PAL           |\
                                 V4L2_STD_PAL_N         |\
                                 V4L2_STD_PAL_Nc        |\
                                 V4L2_STD_SECAM)

#define V4L2_STD_UNKNOWN        0
#define V4L2_STD_ALL            (V4L2_STD_525_60        |\
                                 V4L2_STD_625_50)</PRE
></P
><DIV
CLASS="TABLE"
><A
NAME="VIDEO-STANDARDS"
></A
><P
><B
>Table 4. Video Standards (based on [<A
HREF="b17127.htm#ITU470"
><ABBR
CLASS="ABBREV"
>ITU&nbsp;BT.470</ABBR
></A
>])</B
></P
><TABLE
BORDER="1"
RULES="all"
WIDTH="100%"
CLASS="CALSTABLE"
><COL
WIDTH="12%"
ALIGN="LEFT"
TITLE="C1"><COL
WIDTH="12%"
TITLE="C2"><COL
WIDTH="12%"
TITLE="C3"><COL
WIDTH="12%"
TITLE="C4"><COL
WIDTH="12%"
TITLE="C5"><COL><COL
WIDTH="12%"
TITLE="C7"><COL><COL
WIDTH="12%"
TITLE="C9"><COL><COL><COL
WIDTH="12%"
TITLE="C12"><THEAD
><TR
><TH
>Characteristics</TH
><TH
><P
>M/NTSC<SUP
>a</SUP
></P
></TH
><TH
>M/PAL</TH
><TH
><P
>N/PAL<SUP
>b</SUP
></P
></TH
><TH
ALIGN="CENTER"
>B, B1, G/PAL</TH
><TH
ALIGN="CENTER"
>D, D1, K/PAL</TH
><TH
ALIGN="CENTER"
>H/PAL</TH
><TH
ALIGN="CENTER"
>I/PAL</TH
><TH
ALIGN="CENTER"
>B, G/SECAM</TH
><TH
ALIGN="CENTER"
>D, K/SECAM</TH
><TH
ALIGN="CENTER"
>K1/SECAM</TH
><TH
ALIGN="CENTER"
>L/SECAM</TH
></TR
></THEAD
><TBODY
VALIGN="TOP"
><TR
><TD
>Frame lines</TD
><TD
COLSPAN="2"
ALIGN="CENTER"
>525</TD
><TD
COLSPAN="9"
ALIGN="CENTER"
>625</TD
></TR
><TR
><TD
>Frame period (s)</TD
><TD
COLSPAN="2"
ALIGN="CENTER"
>1001/30000</TD
><TD
COLSPAN="9"
ALIGN="CENTER"
>1/25</TD
></TR
><TR
><TD
>Chrominance sub-carrier frequency (Hz)</TD
><TD
>3579545 &plusmn;&nbsp;10</TD
><TD
>3579611.49 &plusmn;&nbsp;10</TD
><TD
>4433618.75 &plusmn;&nbsp;5 (3582056.25
&plusmn;&nbsp;5)</TD
><TD
COLSPAN="3"
ALIGN="CENTER"
>4433618.75 &plusmn;&nbsp;5</TD
><TD
>4433618.75 &plusmn;&nbsp;1</TD
><TD
COLSPAN="4"
ALIGN="CENTER"
>f<SUB
>OR</SUB
>&nbsp;=
4406250 &plusmn;&nbsp;2000, f<SUB
>OB</SUB
>&nbsp;= 4250000
&plusmn;&nbsp;2000</TD
></TR
><TR
><TD
>Nominal radio-frequency channel bandwidth
(MHz)</TD
><TD
>6</TD
><TD
>6</TD
><TD
>6</TD
><TD
>B: 7; B1, G: 8</TD
><TD
>8</TD
><TD
>8</TD
><TD
>8</TD
><TD
>8</TD
><TD
>8</TD
><TD
>8</TD
><TD
>8</TD
></TR
><TR
><TD
>Sound carrier relative to vision carrier
(MHz)</TD
><TD
>+&nbsp;4.5</TD
><TD
>+&nbsp;4.5</TD
><TD
>+&nbsp;4.5</TD
><TD
><P
>+&nbsp;5.5 &plusmn;&nbsp;0.001
<SUP
>c</SUP
> <SUP
>d</SUP
> <SUP
>e</SUP
> <SUP
>f</SUP
></P
></TD
><TD
>+&nbsp;6.5 &plusmn;&nbsp;0.001</TD
><TD
>+&nbsp;5.5</TD
><TD
>+&nbsp;5.9996 &plusmn;&nbsp;0.0005</TD
><TD
>+&nbsp;5.5 &plusmn;&nbsp;0.001</TD
><TD
>+&nbsp;6.5 &plusmn;&nbsp;0.001</TD
><TD
>+&nbsp;6.5</TD
><TD
><P
>+&nbsp;6.5 <SUP
>g</SUP
></P
></TD
></TR
></TBODY
><TR
><TD
COLSPAN="12"
>Notes:<BR><A
NAME="FTN.AEN9452"
>a. </A
>Japan uses a standard
similar to M/NTSC
(V4L2_STD_NTSC_M_JP).<BR><A
NAME="FTN.AEN9457"
>b. </A
> The values in
brackets apply to the combination N/PAL a.k.a.
N<SUB
>C</SUB
> used in Argentina
(V4L2_STD_PAL_Nc).<BR><A
NAME="FTN.AEN9507"
>c. </A
>In the Federal Republic of Germany, Austria, Italy,
the Netherlands, Slovakia and Switzerland a system of two sound
carriers is used, the frequency of the second carrier being
242.1875&nbsp;kHz above the frequency of the first sound carrier. For
stereophonic sound transmissions a similar system is used in
Australia.<BR><A
NAME="FTN.AEN9509"
>d. </A
>New Zealand uses a sound
carrier displaced 5.4996 &plusmn;&nbsp;0.0005 MHz from the vision
carrier.<BR><A
NAME="FTN.AEN9511"
>e. </A
>In Denmark, Finland, New
Zealand, Sweden and Spain a system of two sound carriers is used. In
Iceland, Norway and Poland the same system is being introduced. The
second carrier is 5.85&nbsp;MHz above the vision carrier and is DQPSK
modulated with 728&nbsp;kbit/s sound and data multiplex. (NICAM
system)<BR><A
NAME="FTN.AEN9513"
>f. </A
>In the United Kingdom, a
system of two sound carriers is used. The second sound carrier is
6.552&nbsp;MHz above the vision carrier and is DQPSK modulated with a
728&nbsp;kbit/s sound and data multiplex able to carry two sound
channels. (NICAM system)<BR><A
NAME="FTN.AEN9523"
>g. </A
>In France, a
digital carrier 5.85 MHz away from the vision carrier may be used in
addition to the main sound carrier. It is modulated in differentially
encoded QPSK with a 728 kbit/s sound and data multiplexer capable of
carrying two sound channels. (NICAM
system)<BR></TD
></TR
></TABLE
></DIV
></DIV
><DIV
CLASS="REFSECT1"
><A
NAME="AEN9525"
></A
><H2
>Return Value</H2
><P
>On success <SPAN
CLASS="RETURNVALUE"
>0</SPAN
> is returned, on error <SPAN
CLASS="RETURNVALUE"
>-1</SPAN
> and the <CODE
CLASS="VARNAME"
>errno</CODE
> variable is set appropriately:</P
><P
></P
><DIV
CLASS="VARIABLELIST"
><DL
><DT
><SPAN
CLASS="ERRORCODE"
>EINVAL</SPAN
></DT
><DD
><P
>The struct&nbsp;<A
HREF="r9288.htm#V4L2-STANDARD"
>v4l2_standard</A
> <CODE
CLASS="STRUCTFIELD"
>index</CODE
>
is out of bounds.</P
></DD
></DL
></DIV
></DIV
><H2
CLASS="FOOTNOTES"
>Notes</H2
><TABLE
BORDER="0"
CLASS="FOOTNOTES"
WIDTH="100%"
><TR
><TD
ALIGN="LEFT"
VALIGN="TOP"
WIDTH="5%"
><A
NAME="FTN.AEN9334"
HREF="r9288.htm#AEN9334"
><SPAN
CLASS="footnote"
>[1]</SPAN
></A
></TD
><TD
ALIGN="LEFT"
VALIGN="TOP"
WIDTH="95%"
><P
>The supported standards may overlap and we need an
unambiguous set to find the current standard returned by
<CODE
CLASS="CONSTANT"
>VIDIOC_G_STD</CODE
>.</P
></TD
></TR
></TABLE
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