Gitiles
Code Review Sign In
gerrit-public.fairphone.software / platform / external / ltp / ec6edca7aa42b6affd989ef91b5897f96795e40f / . / testcases / kernel / device-drivers / v4l / user_space / doc / spec / x15446.htm
blob: f6d6502e2993996170f1a353b53b151554fa07b0 [file] [log] [blame]
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN""http://www.w3.org/TR/html4/loose.dtd">
<HTML
><HEAD
><TITLE
>Changes of the V4L2 API</TITLE
><META
NAME="GENERATOR"
CONTENT="Modular DocBook HTML Stylesheet Version 1.79"><LINK
REL="HOME"
TITLE="Video for Linux Two API Specification"
HREF="book1.htm"><LINK
REL="UP"
TITLE="Changes"
HREF="c14595.htm"><LINK
REL="PREVIOUS"
TITLE="Changes"
HREF="c14595.htm"><LINK
REL="NEXT"
TITLE="Relation of V4L2 to other Linux multimedia APIs"
HREF="x16430.htm"></HEAD
><BODY
CLASS="SECTION"
BGCOLOR="#FFFFFF"
TEXT="#000000"
LINK="#0000FF"
VLINK="#840084"
ALINK="#0000FF"
><DIV
CLASS="NAVHEADER"
><TABLE
SUMMARY="Header navigation table"
WIDTH="100%"
BORDER="0"
CELLPADDING="0"
CELLSPACING="0"
><TR
><TH
COLSPAN="3"
ALIGN="center"
>Video for Linux Two API Specification: Revision 0.24</TH
></TR
><TR
><TD
WIDTH="10%"
ALIGN="left"
VALIGN="bottom"
><A
HREF="c14595.htm"
ACCESSKEY="P"
>Prev</A
></TD
><TD
WIDTH="80%"
ALIGN="center"
VALIGN="bottom"
>Chapter 6. Changes</TD
><TD
WIDTH="10%"
ALIGN="right"
VALIGN="bottom"
><A
HREF="x16430.htm"
ACCESSKEY="N"
>Next</A
></TD
></TR
></TABLE
><HR
ALIGN="LEFT"
WIDTH="100%"></DIV
><DIV
CLASS="SECTION"
><H1
CLASS="SECTION"
><A
NAME="HIST-V4L2"
>6.2. Changes of the V4L2 API</A
></H1
><P
>Soon after the V4L API was added to the kernel it was
criticised as too inflexible. In August 1998 Bill Dirks proposed a
number of improvements and began to work on documentation, example
drivers and applications. With the help of other volunteers this
eventually became the V4L2 API, not just an extension but a
replacement for the V4L API. However it took another four years and
two stable kernel releases until the new API was finally accepted for
inclusion into the kernel in its present form.</P
><DIV
CLASS="SECTION"
><H2
CLASS="SECTION"
><A
NAME="AEN15449"
>6.2.1. Early Versions</A
></H2
><P
>1998-08-20: First version.</P
><P
>1998-08-27: The <A
HREF="r14390.htm"
><CODE
CLASS="FUNCTION"
>select()</CODE
></A
> function was introduced.</P
><P
>1998-09-10: New video standard interface.</P
><P
>1998-09-18: The <CODE
CLASS="CONSTANT"
>VIDIOC_NONCAP</CODE
> ioctl
was replaced by the otherwise meaningless <CODE
CLASS="CONSTANT"
>O_TRUNC</CODE
>
<A
HREF="r14090.htm"
><CODE
CLASS="FUNCTION"
>open()</CODE
></A
> flag, and the aliases <CODE
CLASS="CONSTANT"
>O_NONCAP</CODE
> and
<CODE
CLASS="CONSTANT"
>O_NOIO</CODE
> were defined. Applications can set this
flag if they intend to access controls only, as opposed to capture
applications which need exclusive access. The
<CODE
CLASS="CONSTANT"
>VIDEO_STD_XXX</CODE
> identifiers are now ordinals
instead of flags, and the <CODE
CLASS="FUNCTION"
>video_std_construct()</CODE
>
helper function takes id and transmission arguments.</P
><P
>1998-09-28: Revamped video standard. Made video controls
individually enumerable.</P
><P
>1998-10-02: The <CODE
CLASS="STRUCTFIELD"
>id</CODE
> field was
removed from struct <CODE
CLASS="STRUCTNAME"
>video_standard</CODE
> and the
color subcarrier fields were renamed. The <A
HREF="r13641.htm"
><CODE
CLASS="CONSTANT"
>VIDIOC_QUERYSTD</CODE
></A
> ioctl was
renamed to <A
HREF="r9288.htm"
><CODE
CLASS="CONSTANT"
>VIDIOC_ENUMSTD</CODE
></A
>, <A
HREF="r11217.htm"
><CODE
CLASS="CONSTANT"
>VIDIOC_G_INPUT</CODE
></A
> to <A
HREF="r8936.htm"
><CODE
CLASS="CONSTANT"
>VIDIOC_ENUMINPUT</CODE
></A
>. A
first draft of the Codec API was released.</P
><P
>1998-11-08: Many minor changes. Most symbols have been
renamed. Some material changes to struct&nbsp;<A
HREF="r13105.htm#V4L2-CAPABILITY"
>v4l2_capability</A
>.</P
><P
>1998-11-12: The read/write directon of some ioctls was misdefined.</P
><P
>1998-11-14: <CODE
CLASS="CONSTANT"
>V4L2_PIX_FMT_RGB24</CODE
>
changed to <CODE
CLASS="CONSTANT"
>V4L2_PIX_FMT_BGR24</CODE
>, and
<CODE
CLASS="CONSTANT"
>V4L2_PIX_FMT_RGB32</CODE
> changed to
<CODE
CLASS="CONSTANT"
>V4L2_PIX_FMT_BGR32</CODE
>. Audio controls are now
accessible with the <A
HREF="r10104.htm"
><CODE
CLASS="CONSTANT"
>VIDIOC_G_CTRL</CODE
></A
> and <A
HREF="r10104.htm"
><CODE
CLASS="CONSTANT"
>VIDIOC_S_CTRL</CODE
></A
> ioctls under
names starting with <CODE
CLASS="CONSTANT"
>V4L2_CID_AUDIO</CODE
>. The
<CODE
CLASS="CONSTANT"
>V4L2_MAJOR</CODE
> define was removed from
<TT
CLASS="FILENAME"
>videodev.h</TT
> since it was only used once in the
<TT
CLASS="FILENAME"
>videodev</TT
> kernel module. The
<CODE
CLASS="CONSTANT"
>YUV422</CODE
> and <CODE
CLASS="CONSTANT"
>YUV411</CODE
> planar
image formats were added.</P
><P
>1998-11-28: A few ioctl symbols changed. Interfaces for codecs and
video output devices were added.</P
><P
>1999-01-14: A raw VBI capture interface was added.</P
><P
>1999-01-19: The <CODE
CLASS="CONSTANT"
>VIDIOC_NEXTBUF</CODE
> ioctl
was removed.</P
></DIV
><DIV
CLASS="SECTION"
><H2
CLASS="SECTION"
><A
NAME="AEN15499"
>6.2.2. V4L2 Version 0.16 1999-01-31</A
></H2
><P
>1999-01-27: There is now one QBUF ioctl, VIDIOC_QWBUF and VIDIOC_QRBUF
are gone. VIDIOC_QBUF takes a v4l2_buffer as a parameter. Added
digital zoom (cropping) controls.</P
></DIV
><DIV
CLASS="SECTION"
><H2
CLASS="SECTION"
><A
NAME="AEN15502"
>6.2.3. V4L2 Version 0.18 1999-03-16</A
></H2
><P
>Added a v4l to V4L2 ioctl compatibility layer to
videodev.c. Driver writers, this changes how you implement your ioctl
handler. See the Driver Writer's Guide. Added some more control id
codes.</P
></DIV
><DIV
CLASS="SECTION"
><H2
CLASS="SECTION"
><A
NAME="AEN15505"
>6.2.4. V4L2 Version 0.19 1999-06-05</A
></H2
><P
>1999-03-18: Fill in the category and catname fields of
v4l2_queryctrl objects before passing them to the driver. Required a
minor change to the VIDIOC_QUERYCTRL handlers in the sample
drivers.</P
><P
>1999-03-31: Better compatibility for v4l memory capture
ioctls. Requires changes to drivers to fully support new compatibility
features, see Driver Writer's Guide and v4l2cap.c. Added new control
IDs: V4L2_CID_HFLIP, _VFLIP. Changed V4L2_PIX_FMT_YUV422P to _YUV422P,
and _YUV411P to _YUV411P.</P
><P
>1999-04-04: Added a few more control IDs.</P
><P
>1999-04-07: Added the button control type.</P
><P
>1999-05-02: Fixed a typo in videodev.h, and added the
V4L2_CTRL_FLAG_GRAYED (later V4L2_CTRL_FLAG_GRABBED) flag.</P
><P
>1999-05-20: Definition of VIDIOC_G_CTRL was wrong causing
a malfunction of this ioctl.</P
><P
>1999-06-05: Changed the value of
V4L2_CID_WHITENESS.</P
></DIV
><DIV
CLASS="SECTION"
><H2
CLASS="SECTION"
><A
NAME="AEN15514"
>6.2.5. V4L2 Version 0.20 (1999-09-10)</A
></H2
><P
>Version 0.20 introduced a number of changes which were
<SPAN
CLASS="emphasis"
><I
CLASS="EMPHASIS"
>not backward compatible</I
></SPAN
> with 0.19 and earlier
versions. Purpose of these changes was to simplify the API, while
making it more extensible and following common Linux driver API
conventions.</P
><P
></P
><OL
TYPE="1"
><LI
><P
>Some typos in <CODE
CLASS="CONSTANT"
>V4L2_FMT_FLAG</CODE
>
symbols were fixed. struct&nbsp;<A
HREF="x6570.htm#V4L2-CLIP"
>v4l2_clip</A
> was changed for compatibility with
v4l. (1999-08-30)</P
></LI
><LI
><P
><CODE
CLASS="CONSTANT"
>V4L2_TUNER_SUB_LANG1</CODE
> was added.
(1999-09-05)</P
></LI
><LI
><P
>All ioctl() commands that used an integer argument now
take a pointer to an integer. Where it makes sense, ioctls will return
the actual new value in the integer pointed to by the argument, a
common convention in the V4L2 API. The affected ioctls are:
VIDIOC_PREVIEW, VIDIOC_STREAMON, VIDIOC_STREAMOFF, VIDIOC_S_FREQ,
VIDIOC_S_INPUT, VIDIOC_S_OUTPUT, VIDIOC_S_EFFECT. For example
<PRE
CLASS="PROGRAMLISTING"
>err = ioctl (fd, VIDIOC_XXX, V4L2_XXX);</PRE
> becomes <PRE
CLASS="PROGRAMLISTING"
>int a = V4L2_XXX; err = ioctl(fd, VIDIOC_XXX, &amp;a);</PRE
>
</P
></LI
><LI
><P
>All the different get- and set-format commands were
swept into one <A
HREF="r10944.htm"
><CODE
CLASS="CONSTANT"
>VIDIOC_G_FMT</CODE
></A
> and <A
HREF="r10944.htm"
><CODE
CLASS="CONSTANT"
>VIDIOC_S_FMT</CODE
></A
> ioctl taking a union
and a type field selecting the union member as parameter. Purpose is to
simplify the API by eliminating several ioctls and to allow new and
driver private data streams without adding new ioctls.</P
><P
>This change obsoletes the following ioctls:
<CODE
CLASS="CONSTANT"
>VIDIOC_S_INFMT</CODE
>,
<CODE
CLASS="CONSTANT"
>VIDIOC_G_INFMT</CODE
>,
<CODE
CLASS="CONSTANT"
>VIDIOC_S_OUTFMT</CODE
>,
<CODE
CLASS="CONSTANT"
>VIDIOC_G_OUTFMT</CODE
>,
<CODE
CLASS="CONSTANT"
>VIDIOC_S_VBIFMT</CODE
> and
<CODE
CLASS="CONSTANT"
>VIDIOC_G_VBIFMT</CODE
>. The image format structure
<CODE
CLASS="STRUCTNAME"
>v4l2_format</CODE
> was renamed to struct&nbsp;<A
HREF="c2030.htm#V4L2-PIX-FORMAT"
>v4l2_pix_format</A
>,
while struct&nbsp;<A
HREF="r10944.htm#V4L2-FORMAT"
>v4l2_format</A
> is now the envelopping structure for all format
negotiations.</P
></LI
><LI
><P
>Similar to the changes above, the
<CODE
CLASS="CONSTANT"
>VIDIOC_G_PARM</CODE
> and
<CODE
CLASS="CONSTANT"
>VIDIOC_S_PARM</CODE
> ioctls were merged with
<CODE
CLASS="CONSTANT"
>VIDIOC_G_OUTPARM</CODE
> and
<CODE
CLASS="CONSTANT"
>VIDIOC_S_OUTPARM</CODE
>. A
<CODE
CLASS="STRUCTFIELD"
>type</CODE
> field in the new struct&nbsp;<A
HREF="r11680.htm#V4L2-STREAMPARM"
>v4l2_streamparm</A
>
selects the respective union member.</P
><P
>This change obsoletes the
<CODE
CLASS="CONSTANT"
>VIDIOC_G_OUTPARM</CODE
> and
<CODE
CLASS="CONSTANT"
>VIDIOC_S_OUTPARM</CODE
> ioctls.</P
></LI
><LI
><P
>Control enumeration was simplified, and two new
control flags were introduced and one dropped. The
<CODE
CLASS="STRUCTFIELD"
>catname</CODE
> field was replaced by a
<CODE
CLASS="STRUCTFIELD"
>group</CODE
> field.</P
><P
>Drivers can now flag unsupported and temporarily
unavailable controls with <CODE
CLASS="CONSTANT"
>V4L2_CTRL_FLAG_DISABLED</CODE
>
and <CODE
CLASS="CONSTANT"
>V4L2_CTRL_FLAG_GRABBED</CODE
> respectively. The
<CODE
CLASS="STRUCTFIELD"
>group</CODE
> name indicates a possibly narrower
classification than the <CODE
CLASS="STRUCTFIELD"
>category</CODE
>. In other
words, there may be multiple groups within a category. Controls within
a group would typically be drawn within a group box. Controls in
different categories might have a greater separation, or may even
appear in separate windows.</P
></LI
><LI
><P
>The struct&nbsp;<A
HREF="x5953.htm#V4L2-BUFFER"
>v4l2_buffer</A
> <CODE
CLASS="STRUCTFIELD"
>timestamp</CODE
>
was changed to a 64 bit integer, containing the sampling or output
time of the frame in nanoseconds. Additionally timestamps will be in
absolute system time, not starting from zero at the beginning of a
stream. The data type name for timestamps is stamp_t, defined as a
signed 64-bit integer. Output devices should not send a buffer out
until the time in the timestamp field has arrived. I would like to
follow SGI's lead, and adopt a multimedia timestamping system like
their UST (Unadjusted System Time). See
http://reality.sgi.com/cpirazzi_engr/lg/time/intro.html. [This link is
no longer valid.] UST uses timestamps that are 64-bit signed integers
(not struct timeval's) and given in nanosecond units. The UST clock
starts at zero when the system is booted and runs continuously and
uniformly. It takes a little over 292 years for UST to overflow. There
is no way to set the UST clock. The regular Linux time-of-day clock
can be changed periodically, which would cause errors if it were being
used for timestamping a multimedia stream. A real UST style clock will
require some support in the kernel that is not there yet. But in
anticipation, I will change the timestamp field to a 64-bit integer,
and I will change the v4l2_masterclock_gettime() function (used only
by drivers) to return a 64-bit integer.</P
></LI
><LI
><P
>A <CODE
CLASS="STRUCTFIELD"
>sequence</CODE
> field was added
to struct&nbsp;<A
HREF="x5953.htm#V4L2-BUFFER"
>v4l2_buffer</A
>. The <CODE
CLASS="STRUCTFIELD"
>sequence</CODE
> field counts
captured frames, it is ignored by output devices. When a capture
driver drops a frame, the sequence number of that frame is
skipped.</P
></LI
></OL
></DIV
><DIV
CLASS="SECTION"
><H2
CLASS="SECTION"
><A
NAME="AEN15575"
>6.2.6. V4L2 Version 0.20 incremental changes</A
></H2
><P
>1999-12-23: In struct&nbsp;<A
HREF="x7013.htm#V4L2-VBI-FORMAT"
>v4l2_vbi_format</A
> the
<CODE
CLASS="STRUCTFIELD"
>reserved1</CODE
> field became
<CODE
CLASS="STRUCTFIELD"
>offset</CODE
>. Previously drivers were required to
clear the <CODE
CLASS="STRUCTFIELD"
>reserved1</CODE
> field.</P
><P
>2000-01-13: The
<CODE
CLASS="CONSTANT"
>V4L2_FMT_FLAG_NOT_INTERLACED</CODE
> flag was added.</P
><P
>2000-07-31: The <TT
CLASS="FILENAME"
>linux/poll.h</TT
> header
is now included by <TT
CLASS="FILENAME"
>videodev.h</TT
> for compatibility
with the original <TT
CLASS="FILENAME"
>videodev.h</TT
> file.</P
><P
>2000-11-20: <CODE
CLASS="CONSTANT"
>V4L2_TYPE_VBI_OUTPUT</CODE
> and
<CODE
CLASS="CONSTANT"
>V4L2_PIX_FMT_Y41P</CODE
> were added.</P
><P
>2000-11-25: <CODE
CLASS="CONSTANT"
>V4L2_TYPE_VBI_INPUT</CODE
> was
added.</P
><P
>2000-12-04: A couple typos in symbol names were fixed.</P
><P
>2001-01-18: To avoid namespace conflicts the
<CODE
CLASS="CONSTANT"
>fourcc</CODE
> macro defined in the
<TT
CLASS="FILENAME"
>videodev.h</TT
> header file was renamed to
<CODE
CLASS="CONSTANT"
>v4l2_fourcc</CODE
>.</P
><P
>2001-01-25: A possible driver-level compatibility problem
between the <TT
CLASS="FILENAME"
>videodev.h</TT
> file in Linux 2.4.0 and
the <TT
CLASS="FILENAME"
>videodev.h</TT
> file included in the
<TT
CLASS="FILENAME"
>videodevX</TT
> patch was fixed. Users of an earlier
version of <TT
CLASS="FILENAME"
>videodevX</TT
> on Linux 2.4.0 should
recompile their V4L and V4L2 drivers.</P
><P
>2001-01-26: A possible kernel-level incompatibility
between the <TT
CLASS="FILENAME"
>videodev.h</TT
> file in the
<TT
CLASS="FILENAME"
>videodevX</TT
> patch and the
<TT
CLASS="FILENAME"
>videodev.h</TT
> file in Linux 2.2.x with devfs patches
applied was fixed.</P
><P
>2001-03-02: Certain V4L ioctls which pass data in both
direction although they are defined with read-only parameter, did not
work correctly through the backward compatibility layer.
[Solution?]</P
><P
>2001-04-13: Big endian 16-bit RGB formats were added.</P
><P
>2001-09-17: New YUV formats and the <A
HREF="r11094.htm"
><CODE
CLASS="CONSTANT"
>VIDIOC_G_FREQUENCY</CODE
></A
> and
<A
HREF="r11094.htm"
><CODE
CLASS="CONSTANT"
>VIDIOC_S_FREQUENCY</CODE
></A
> ioctls were added. (The old
<CODE
CLASS="CONSTANT"
>VIDIOC_G_FREQ</CODE
> and
<CODE
CLASS="CONSTANT"
>VIDIOC_S_FREQ</CODE
> ioctls did not take multiple tuners
into account.)</P
><P
>2000-09-18: <CODE
CLASS="CONSTANT"
>V4L2_BUF_TYPE_VBI</CODE
> was
added. This may <SPAN
CLASS="emphasis"
><I
CLASS="EMPHASIS"
>break compatibility</I
></SPAN
> as the
<A
HREF="r10944.htm"
><CODE
CLASS="CONSTANT"
>VIDIOC_G_FMT</CODE
></A
> and <A
HREF="r10944.htm"
><CODE
CLASS="CONSTANT"
>VIDIOC_S_FMT</CODE
></A
> ioctls may fail now if the struct
<CODE
CLASS="STRUCTNAME"
>v4l2_fmt</CODE
> <CODE
CLASS="STRUCTFIELD"
>type</CODE
>
field does not contain <CODE
CLASS="CONSTANT"
>V4L2_BUF_TYPE_VBI</CODE
>. In the
documentation of the struct&nbsp;<A
HREF="x7013.htm#V4L2-VBI-FORMAT"
>v4l2_vbi_format</A
>
<CODE
CLASS="STRUCTFIELD"
>offset</CODE
> field the ambiguous phrase "rising
edge" was changed to "leading edge".</P
></DIV
><DIV
CLASS="SECTION"
><H2
CLASS="SECTION"
><A
NAME="AEN15628"
>6.2.7. V4L2 Version 0.20 2000-11-23</A
></H2
><P
>A number of changes were made to the raw VBI
interface.</P
><P
></P
><OL
TYPE="1"
><LI
><P
>Figures clarifying the line numbering scheme were
added to the V4L2 API specification. The
<CODE
CLASS="STRUCTFIELD"
>start</CODE
>[0] and
<CODE
CLASS="STRUCTFIELD"
>start</CODE
>[1] fields no longer count line
numbers beginning at zero. Rationale: a) The previous definition was
unclear. b) The <CODE
CLASS="STRUCTFIELD"
>start</CODE
>[] values are ordinal
numbers. c) There is no point in inventing a new line numbering
scheme. We now use line number as defined by ITU-R, period.
Compatibility: Add one to the start values. Applications depending on
the previous semantics may not function correctly.</P
></LI
><LI
><P
>The restriction "count[0] &gt; 0 and count[1] &gt; 0"
has been relaxed to "(count[0] + count[1]) &gt; 0". Rationale:
Drivers may allocate resources at scan line granularity and some data
services are transmitted only on the first field. The comment that
both <CODE
CLASS="STRUCTFIELD"
>count</CODE
> values will usually be equal is
misleading and pointless and has been removed. This change
<SPAN
CLASS="emphasis"
><I
CLASS="EMPHASIS"
>breaks compatibility</I
></SPAN
> with earlier versions:
Drivers may return EINVAL, applications may not function
correctly.</P
></LI
><LI
><P
>Drivers are again permitted to return negative
(unknown) start values as proposed earlier. Why this feature was
dropped is unclear. This change may <SPAN
CLASS="emphasis"
><I
CLASS="EMPHASIS"
>break
compatibility</I
></SPAN
> with applications depending on the start
values being positive. The use of <CODE
CLASS="CONSTANT"
>EBUSY</CODE
> and
<CODE
CLASS="CONSTANT"
>EINVAL</CODE
> error codes with the <A
HREF="r10944.htm"
><CODE
CLASS="CONSTANT"
>VIDIOC_S_FMT</CODE
></A
> ioctl
was clarified. The <SPAN
CLASS="ERRORCODE"
>EBUSY</SPAN
> error code was finally documented, and the
<CODE
CLASS="STRUCTFIELD"
>reserved2</CODE
> field which was previously
mentioned only in the <TT
CLASS="FILENAME"
>videodev.h</TT
> header
file.</P
></LI
><LI
><P
>New buffer types
<CODE
CLASS="CONSTANT"
>V4L2_TYPE_VBI_INPUT</CODE
> and
<CODE
CLASS="CONSTANT"
>V4L2_TYPE_VBI_OUTPUT</CODE
> were added. The former is an
alias for the old <CODE
CLASS="CONSTANT"
>V4L2_TYPE_VBI</CODE
>, the latter was
missing in the <TT
CLASS="FILENAME"
>videodev.h</TT
> file.</P
></LI
></OL
></DIV
><DIV
CLASS="SECTION"
><H2
CLASS="SECTION"
><A
NAME="AEN15657"
>6.2.8. V4L2 Version 0.20 2002-07-25</A
></H2
><P
>Added sliced VBI interface proposal.</P
></DIV
><DIV
CLASS="SECTION"
><H2
CLASS="SECTION"
><A
NAME="AEN15660"
>6.2.9. V4L2 in Linux 2.5.46, 2002-10</A
></H2
><P
>Around October-November 2002, prior to an announced
feature freeze of Linux 2.5, the API was revised, drawing from
experience with V4L2 0.20. This unnamed version was finally merged
into Linux 2.5.46.</P
><P
></P
><OL
TYPE="1"
><LI
><P
>As specified in <A
HREF="c174.htm#RELATED"
>Section 1.1.2</A
>, drivers
must make related device functions available under all minor device
numbers.</P
></LI
><LI
><P
>The <A
HREF="r14090.htm"
><CODE
CLASS="FUNCTION"
>open()</CODE
></A
> function requires access mode
<CODE
CLASS="CONSTANT"
>O_RDWR</CODE
> regardless of the device type. All V4L2
drivers exchanging data with applications must support the
<CODE
CLASS="CONSTANT"
>O_NONBLOCK</CODE
> flag. The <CODE
CLASS="CONSTANT"
>O_NOIO</CODE
>
flag, a V4L2 symbol which aliased the meaningless
<CODE
CLASS="CONSTANT"
>O_TRUNC</CODE
> to indicate accesses without data
exchange (panel applications) was dropped. Drivers must stay in "panel
mode" until the application attempts to initiate a data exchange, see
<A
HREF="c174.htm#OPEN"
>Section 1.1</A
>.</P
></LI
><LI
><P
>The struct&nbsp;<A
HREF="r13105.htm#V4L2-CAPABILITY"
>v4l2_capability</A
> changed dramatically. Note that
also the size of the structure changed, which is encoded in the ioctl
request code, thus older V4L2 devices will respond with an <SPAN
CLASS="ERRORCODE"
>EINVAL</SPAN
> error code to
the new <A
HREF="r13105.htm"
><CODE
CLASS="CONSTANT"
>VIDIOC_QUERYCAP</CODE
></A
> ioctl.</P
><P
>There are new fields to identify the driver, a new (as
of yet unspecified) device function
<CODE
CLASS="CONSTANT"
>V4L2_CAP_RDS_CAPTURE</CODE
>, the
<CODE
CLASS="CONSTANT"
>V4L2_CAP_AUDIO</CODE
> flag indicates if the device has
any audio connectors, another I/O capability
<CODE
CLASS="CONSTANT"
>V4L2_CAP_ASYNCIO</CODE
> can be flagged. In response to
these changes the <CODE
CLASS="STRUCTFIELD"
>type</CODE
> field became a bit
set and was merged into the <CODE
CLASS="STRUCTFIELD"
>flags</CODE
> field.
<CODE
CLASS="CONSTANT"
>V4L2_FLAG_TUNER</CODE
> was renamed to
<CODE
CLASS="CONSTANT"
>V4L2_CAP_TUNER</CODE
>,
<CODE
CLASS="CONSTANT"
>V4L2_CAP_VIDEO_OVERLAY</CODE
> replaced
<CODE
CLASS="CONSTANT"
>V4L2_FLAG_PREVIEW</CODE
> and
<CODE
CLASS="CONSTANT"
>V4L2_CAP_VBI_CAPTURE</CODE
> and
<CODE
CLASS="CONSTANT"
>V4L2_CAP_VBI_OUTPUT</CODE
> replaced
<CODE
CLASS="CONSTANT"
>V4L2_FLAG_DATA_SERVICE</CODE
>.
<CODE
CLASS="CONSTANT"
>V4L2_FLAG_READ</CODE
> and
<CODE
CLASS="CONSTANT"
>V4L2_FLAG_WRITE</CODE
> were merged into
<CODE
CLASS="CONSTANT"
>V4L2_CAP_READWRITE</CODE
>.</P
><P
>The redundant fields
<CODE
CLASS="STRUCTFIELD"
>inputs</CODE
>, <CODE
CLASS="STRUCTFIELD"
>outputs</CODE
>
and <CODE
CLASS="STRUCTFIELD"
>audios</CODE
> were removed. These properties
can be determined as described in <A
HREF="x309.htm"
>Section 1.4</A
> and <A
HREF="x341.htm"
>Section 1.5</A
>.</P
><P
>The somewhat volatile and therefore barely useful
fields <CODE
CLASS="STRUCTFIELD"
>maxwidth</CODE
>,
<CODE
CLASS="STRUCTFIELD"
>maxheight</CODE
>,
<CODE
CLASS="STRUCTFIELD"
>minwidth</CODE
>,
<CODE
CLASS="STRUCTFIELD"
>minheight</CODE
>,
<CODE
CLASS="STRUCTFIELD"
>maxframerate</CODE
> were removed. This information
is available as described in <A
HREF="x1859.htm"
>Section 1.10</A
> and
<A
HREF="x448.htm"
>Section 1.7</A
>.</P
><P
><CODE
CLASS="CONSTANT"
>V4L2_FLAG_SELECT</CODE
> was removed. We
believe the select() function is important enough to require support
of it in all V4L2 drivers exchanging data with applications. The
redundant <CODE
CLASS="CONSTANT"
>V4L2_FLAG_MONOCHROME</CODE
> flag was removed,
this information is available as described in <A
HREF="x1859.htm"
>Section 1.10</A
>.</P
></LI
><LI
><P
>In struct&nbsp;<A
HREF="r8936.htm#V4L2-INPUT"
>v4l2_input</A
> the
<CODE
CLASS="STRUCTFIELD"
>assoc_audio</CODE
> field and the
<CODE
CLASS="STRUCTFIELD"
>capability</CODE
> field and its only flag
<CODE
CLASS="CONSTANT"
>V4L2_INPUT_CAP_AUDIO</CODE
> was replaced by the new
<CODE
CLASS="STRUCTFIELD"
>audioset</CODE
> field. Instead of linking one
video input to one audio input this field reports all audio inputs
this video input combines with.</P
><P
>New fields are <CODE
CLASS="STRUCTFIELD"
>tuner</CODE
>
(reversing the former link from tuners to video inputs),
<CODE
CLASS="STRUCTFIELD"
>std</CODE
> and
<CODE
CLASS="STRUCTFIELD"
>status</CODE
>.</P
><P
>Accordingly struct&nbsp;<A
HREF="r9149.htm#V4L2-OUTPUT"
>v4l2_output</A
> lost its
<CODE
CLASS="STRUCTFIELD"
>capability</CODE
> and
<CODE
CLASS="STRUCTFIELD"
>assoc_audio</CODE
> fields.
<CODE
CLASS="STRUCTFIELD"
>audioset</CODE
>,
<CODE
CLASS="STRUCTFIELD"
>modulator</CODE
> and
<CODE
CLASS="STRUCTFIELD"
>std</CODE
> where added instead.</P
></LI
><LI
><P
>The struct&nbsp;<A
HREF="r9539.htm#V4L2-AUDIO"
>v4l2_audio</A
> field
<CODE
CLASS="STRUCTFIELD"
>audio</CODE
> was renamed to
<CODE
CLASS="STRUCTFIELD"
>index</CODE
>, for consistency with other
structures. A new capability flag
<CODE
CLASS="CONSTANT"
>V4L2_AUDCAP_STEREO</CODE
> was added to indicated if the
audio input in question supports stereo sound.
<CODE
CLASS="CONSTANT"
>V4L2_AUDCAP_EFFECTS</CODE
> and the corresponding
<CODE
CLASS="CONSTANT"
>V4L2_AUDMODE</CODE
> flags where removed. This can be
easily implemented using controls. (However the same applies to AVL
which is still there.)</P
><P
>Again for consistency the struct&nbsp;<A
HREF="r9688.htm#V4L2-AUDIOOUT"
>v4l2_audioout</A
> field
<CODE
CLASS="STRUCTFIELD"
>audio</CODE
> was renamed to
<CODE
CLASS="STRUCTFIELD"
>index</CODE
>.</P
></LI
><LI
><P
>The struct&nbsp;<A
HREF="r12342.htm#V4L2-TUNER"
>v4l2_tuner</A
>
<CODE
CLASS="STRUCTFIELD"
>input</CODE
> field was replaced by an
<CODE
CLASS="STRUCTFIELD"
>index</CODE
> field, permitting devices with
multiple tuners. The link between video inputs and tuners is now
reversed, inputs point to their tuner. The
<CODE
CLASS="STRUCTFIELD"
>std</CODE
> substructure became a
simple set (more about this below) and moved into struct&nbsp;<A
HREF="r8936.htm#V4L2-INPUT"
>v4l2_input</A
>. A
<CODE
CLASS="STRUCTFIELD"
>type</CODE
> field was added.</P
><P
>Accordingly in struct&nbsp;<A
HREF="r11430.htm#V4L2-MODULATOR"
>v4l2_modulator</A
> the
<CODE
CLASS="STRUCTFIELD"
>output</CODE
> was replaced by an
<CODE
CLASS="STRUCTFIELD"
>index</CODE
> field.</P
><P
>In struct&nbsp;<A
HREF="r11094.htm#V4L2-FREQUENCY"
>v4l2_frequency</A
> the
<CODE
CLASS="STRUCTFIELD"
>port</CODE
> field was replaced by a
<CODE
CLASS="STRUCTFIELD"
>tuner</CODE
> field containing the respective tuner
or modulator index number. A tuner <CODE
CLASS="STRUCTFIELD"
>type</CODE
>
field was added and the <CODE
CLASS="STRUCTFIELD"
>reserved</CODE
> field
became larger for future extensions (satellite tuners in
particular).</P
></LI
><LI
><P
>The idea of completely transparent video standards was
dropped. Experience showed that applications must be able to work with
video standards beyond presenting the user a menu. Instead of
enumerating supported standards with an ioctl applications can now
refer to standards by <A
HREF="r9288.htm#V4L2-STD-ID"
>v4l2_std_id</A
> and symbols defined in the
<TT
CLASS="FILENAME"
>videodev2.h</TT
> header file. For details see <A
HREF="x448.htm"
>Section 1.7</A
>. The <A
HREF="r12265.htm"
><CODE
CLASS="CONSTANT"
>VIDIOC_G_STD</CODE
></A
> and
<A
HREF="r12265.htm"
><CODE
CLASS="CONSTANT"
>VIDIOC_S_STD</CODE
></A
> now take a pointer to this type as argument.
<A
HREF="r13641.htm"
><CODE
CLASS="CONSTANT"
>VIDIOC_QUERYSTD</CODE
></A
> was added to autodetect the received standard, if
the hardware has this capability. In struct&nbsp;<A
HREF="r9288.htm#V4L2-STANDARD"
>v4l2_standard</A
> an
<CODE
CLASS="STRUCTFIELD"
>index</CODE
> field was added for <A
HREF="r9288.htm"
><CODE
CLASS="CONSTANT"
>VIDIOC_ENUMSTD</CODE
></A
>.
A <A
HREF="r9288.htm#V4L2-STD-ID"
>v4l2_std_id</A
> field named <CODE
CLASS="STRUCTFIELD"
>id</CODE
> was added as
machine readable identifier, also replacing the
<CODE
CLASS="STRUCTFIELD"
>transmission</CODE
> field. The misleading
<CODE
CLASS="STRUCTFIELD"
>framerate</CODE
> field was renamed
to <CODE
CLASS="STRUCTFIELD"
>frameperiod</CODE
>. The now obsolete
<CODE
CLASS="STRUCTFIELD"
>colorstandard</CODE
> information, originally
needed to distguish between variations of standards, were
removed.</P
><P
>Struct <CODE
CLASS="STRUCTNAME"
>v4l2_enumstd</CODE
> ceased to
be. <A
HREF="r9288.htm"
><CODE
CLASS="CONSTANT"
>VIDIOC_ENUMSTD</CODE
></A
> now takes a pointer to a struct&nbsp;<A
HREF="r9288.htm#V4L2-STANDARD"
>v4l2_standard</A
>
directly. The information which standards are supported by a
particular video input or output moved into struct&nbsp;<A
HREF="r8936.htm#V4L2-INPUT"
>v4l2_input</A
> and
struct&nbsp;<A
HREF="r9149.htm#V4L2-OUTPUT"
>v4l2_output</A
> fields named <CODE
CLASS="STRUCTFIELD"
>std</CODE
>,
respectively.</P
></LI
><LI
><P
>The struct&nbsp;<A
HREF="r13317.htm#V4L2-QUERYCTRL"
>v4l2_queryctrl</A
> fields
<CODE
CLASS="STRUCTFIELD"
>category</CODE
> and
<CODE
CLASS="STRUCTFIELD"
>group</CODE
> did not catch on and/or were not
implemented as expected and therefore removed.</P
></LI
><LI
><P
>The <A
HREF="r10944.htm"
><CODE
CLASS="CONSTANT"
>VIDIOC_TRY_FMT</CODE
></A
> ioctl was added to negotiate data
formats as with <A
HREF="r10944.htm"
><CODE
CLASS="CONSTANT"
>VIDIOC_S_FMT</CODE
></A
>, but without the overhead of
programming the hardware and regardless of I/O in progress.</P
><P
>In struct&nbsp;<A
HREF="r10944.htm#V4L2-FORMAT"
>v4l2_format</A
> the <CODE
CLASS="STRUCTFIELD"
>fmt</CODE
>
union was extended to contain struct&nbsp;<A
HREF="x6570.htm#V4L2-WINDOW"
>v4l2_window</A
>. All image format
negotiations are now possible with <CODE
CLASS="CONSTANT"
>VIDIOC_G_FMT</CODE
>,
<CODE
CLASS="CONSTANT"
>VIDIOC_S_FMT</CODE
> and
<CODE
CLASS="CONSTANT"
>VIDIOC_TRY_FMT</CODE
>; ioctl. The
<CODE
CLASS="CONSTANT"
>VIDIOC_G_WIN</CODE
> and
<CODE
CLASS="CONSTANT"
>VIDIOC_S_WIN</CODE
> ioctls to prepare for a video
overlay were removed. The <CODE
CLASS="STRUCTFIELD"
>type</CODE
> field
changed to type enum&nbsp;<A
HREF="x5953.htm#V4L2-BUF-TYPE"
>v4l2_buf_type</A
> and the buffer type names changed as
follows.<DIV
CLASS="INFORMALTABLE"
><P
></P
><A
NAME="AEN15815"
></A
><TABLE
BORDER="1"
CLASS="CALSTABLE"
><COL><COL><THEAD
><TR
><TH
>Old defines</TH
><TH
>enum&nbsp;<A
HREF="x5953.htm#V4L2-BUF-TYPE"
>v4l2_buf_type</A
></TH
></TR
></THEAD
><TBODY
VALIGN="TOP"
><TR
><TD
><CODE
CLASS="CONSTANT"
>V4L2_BUF_TYPE_CAPTURE</CODE
></TD
><TD
><CODE
CLASS="CONSTANT"
>V4L2_BUF_TYPE_VIDEO_CAPTURE</CODE
></TD
></TR
><TR
><TD
><CODE
CLASS="CONSTANT"
>V4L2_BUF_TYPE_CODECIN</CODE
></TD
><TD
>Omitted for now</TD
></TR
><TR
><TD
><CODE
CLASS="CONSTANT"
>V4L2_BUF_TYPE_CODECOUT</CODE
></TD
><TD
>Omitted for now</TD
></TR
><TR
><TD
><CODE
CLASS="CONSTANT"
>V4L2_BUF_TYPE_EFFECTSIN</CODE
></TD
><TD
>Omitted for now</TD
></TR
><TR
><TD
><CODE
CLASS="CONSTANT"
>V4L2_BUF_TYPE_EFFECTSIN2</CODE
></TD
><TD
>Omitted for now</TD
></TR
><TR
><TD
><CODE
CLASS="CONSTANT"
>V4L2_BUF_TYPE_EFFECTSOUT</CODE
></TD
><TD
>Omitted for now</TD
></TR
><TR
><TD
><CODE
CLASS="CONSTANT"
>V4L2_BUF_TYPE_VIDEOOUT</CODE
></TD
><TD
><CODE
CLASS="CONSTANT"
>V4L2_BUF_TYPE_VIDEO_OUTPUT</CODE
></TD
></TR
><TR
><TD
><CODE
CLASS="CONSTANT"
>-</CODE
></TD
><TD
><CODE
CLASS="CONSTANT"
>V4L2_BUF_TYPE_VIDEO_OVERLAY</CODE
></TD
></TR
><TR
><TD
><CODE
CLASS="CONSTANT"
>-</CODE
></TD
><TD
><CODE
CLASS="CONSTANT"
>V4L2_BUF_TYPE_VBI_CAPTURE</CODE
></TD
></TR
><TR
><TD
><CODE
CLASS="CONSTANT"
>-</CODE
></TD
><TD
><CODE
CLASS="CONSTANT"
>V4L2_BUF_TYPE_VBI_OUTPUT</CODE
></TD
></TR
><TR
><TD
><CODE
CLASS="CONSTANT"
>-</CODE
></TD
><TD
><CODE
CLASS="CONSTANT"
>V4L2_BUF_TYPE_SLICED_VBI_CAPTURE</CODE
></TD
></TR
><TR
><TD
><CODE
CLASS="CONSTANT"
>-</CODE
></TD
><TD
><CODE
CLASS="CONSTANT"
>V4L2_BUF_TYPE_SLICED_VBI_OUTPUT</CODE
></TD
></TR
><TR
><TD
><CODE
CLASS="CONSTANT"
>V4L2_BUF_TYPE_PRIVATE_BASE</CODE
></TD
><TD
><CODE
CLASS="CONSTANT"
>V4L2_BUF_TYPE_PRIVATE</CODE
></TD
></TR
></TBODY
></TABLE
><P
></P
></DIV
></P
></LI
><LI
><P
>In struct&nbsp;<A
HREF="r8367.htm#V4L2-FMTDESC"
>v4l2_fmtdesc</A
> a enum&nbsp;<A
HREF="x5953.htm#V4L2-BUF-TYPE"
>v4l2_buf_type</A
> field named
<CODE
CLASS="STRUCTFIELD"
>type</CODE
> was added as in struct&nbsp;<A
HREF="r10944.htm#V4L2-FORMAT"
>v4l2_format</A
>. The
<CODE
CLASS="CONSTANT"
>VIDIOC_ENUM_FBUFFMT</CODE
> ioctl is no longer needed and
was removed. These calls can be replaced by <A
HREF="r8367.htm"
><CODE
CLASS="CONSTANT"
>VIDIOC_ENUM_FMT</CODE
></A
> with
type <CODE
CLASS="CONSTANT"
>V4L2_BUF_TYPE_VIDEO_OVERLAY</CODE
>.</P
></LI
><LI
><P
>In struct&nbsp;<A
HREF="c2030.htm#V4L2-PIX-FORMAT"
>v4l2_pix_format</A
> the
<CODE
CLASS="STRUCTFIELD"
>depth</CODE
> field was removed, assuming
applications which recognize the format by its four-character-code
already know the color depth, and others do not care about it. The
same rationale lead to the removal of the
<CODE
CLASS="CONSTANT"
>V4L2_FMT_FLAG_COMPRESSED</CODE
> flag. The
<CODE
CLASS="CONSTANT"
>V4L2_FMT_FLAG_SWCONVECOMPRESSED</CODE
> flag was removed
because drivers are not supposed to convert images in kernel space. A
user library of conversion functions should be provided instead. The
<CODE
CLASS="CONSTANT"
>V4L2_FMT_FLAG_BYTESPERLINE</CODE
> flag was redundant.
Applications can set the <CODE
CLASS="STRUCTFIELD"
>bytesperline</CODE
> field
to zero to get a reasonable default. Since the remaining flags were
replaced as well, the <CODE
CLASS="STRUCTFIELD"
>flags</CODE
> field itself
was removed.</P
><P
>The interlace flags were replaced by a enum&nbsp;<A
HREF="x6386.htm#V4L2-FIELD"
>v4l2_field</A
>
value in a newly added <CODE
CLASS="STRUCTFIELD"
>field</CODE
>
field.<DIV
CLASS="INFORMALTABLE"
><P
></P
><A
NAME="AEN15905"
></A
><TABLE
BORDER="1"
CLASS="CALSTABLE"
><COL><COL><THEAD
><TR
><TH
>Old flag</TH
><TH
>enum&nbsp;<A
HREF="x6386.htm#V4L2-FIELD"
>v4l2_field</A
></TH
></TR
></THEAD
><TBODY
VALIGN="TOP"
><TR
><TD
><CODE
CLASS="CONSTANT"
>V4L2_FMT_FLAG_NOT_INTERLACED</CODE
></TD
><TD
>?</TD
></TR
><TR
><TD
><CODE
CLASS="CONSTANT"
>V4L2_FMT_FLAG_INTERLACED</CODE
>
= <CODE
CLASS="CONSTANT"
>V4L2_FMT_FLAG_COMBINED</CODE
></TD
><TD
><CODE
CLASS="CONSTANT"
>V4L2_FIELD_INTERLACED</CODE
></TD
></TR
><TR
><TD
><CODE
CLASS="CONSTANT"
>V4L2_FMT_FLAG_TOPFIELD</CODE
>
= <CODE
CLASS="CONSTANT"
>V4L2_FMT_FLAG_ODDFIELD</CODE
></TD
><TD
><CODE
CLASS="CONSTANT"
>V4L2_FIELD_TOP</CODE
></TD
></TR
><TR
><TD
><CODE
CLASS="CONSTANT"
>V4L2_FMT_FLAG_BOTFIELD</CODE
>
= <CODE
CLASS="CONSTANT"
>V4L2_FMT_FLAG_EVENFIELD</CODE
></TD
><TD
><CODE
CLASS="CONSTANT"
>V4L2_FIELD_BOTTOM</CODE
></TD
></TR
><TR
><TD
><CODE
CLASS="CONSTANT"
>-</CODE
></TD
><TD
><CODE
CLASS="CONSTANT"
>V4L2_FIELD_SEQ_TB</CODE
></TD
></TR
><TR
><TD
><CODE
CLASS="CONSTANT"
>-</CODE
></TD
><TD
><CODE
CLASS="CONSTANT"
>V4L2_FIELD_SEQ_BT</CODE
></TD
></TR
><TR
><TD
><CODE
CLASS="CONSTANT"
>-</CODE
></TD
><TD
><CODE
CLASS="CONSTANT"
>V4L2_FIELD_ALTERNATE</CODE
></TD
></TR
></TBODY
></TABLE
><P
></P
></DIV
></P
><P
>The color space flags were replaced by a
enum&nbsp;<A
HREF="x2123.htm#V4L2-COLORSPACE"
>v4l2_colorspace</A
> value in a newly added
<CODE
CLASS="STRUCTFIELD"
>colorspace</CODE
> field, where one of
<CODE
CLASS="CONSTANT"
>V4L2_COLORSPACE_SMPTE170M</CODE
>,
<CODE
CLASS="CONSTANT"
>V4L2_COLORSPACE_BT878</CODE
>,
<CODE
CLASS="CONSTANT"
>V4L2_COLORSPACE_470_SYSTEM_M</CODE
> or
<CODE
CLASS="CONSTANT"
>V4L2_COLORSPACE_470_SYSTEM_BG</CODE
> replaces
<CODE
CLASS="CONSTANT"
>V4L2_FMT_CS_601YUV</CODE
>.</P
></LI
><LI
><P
>In struct&nbsp;<A
HREF="r13696.htm#V4L2-REQUESTBUFFERS"
>v4l2_requestbuffers</A
> the
<CODE
CLASS="STRUCTFIELD"
>type</CODE
> field was properly defined as
enum&nbsp;<A
HREF="x5953.htm#V4L2-BUF-TYPE"
>v4l2_buf_type</A
>. Buffer types changed as mentioned above. A new
<CODE
CLASS="STRUCTFIELD"
>memory</CODE
> field of type enum&nbsp;<A
HREF="x5953.htm#V4L2-MEMORY"
>v4l2_memory</A
> was
added to distinguish between I/O methods using buffers allocated
by the driver or the application. See <A
HREF="c5742.htm"
>Chapter 3</A
> for
details.</P
></LI
><LI
><P
>In struct&nbsp;<A
HREF="x5953.htm#V4L2-BUFFER"
>v4l2_buffer</A
> the <CODE
CLASS="STRUCTFIELD"
>type</CODE
>
field was properly defined as enum&nbsp;<A
HREF="x5953.htm#V4L2-BUF-TYPE"
>v4l2_buf_type</A
>. Buffer types changed as
mentioned above. A <CODE
CLASS="STRUCTFIELD"
>field</CODE
> field of type
enum&nbsp;<A
HREF="x6386.htm#V4L2-FIELD"
>v4l2_field</A
> was added to indicate if a buffer contains a top or
bottom field. The old field flags were removed. Since no unadjusted
system time clock was added to the kernel as planned, the
<CODE
CLASS="STRUCTFIELD"
>timestamp</CODE
> field changed back from type
stamp_t, an unsigned 64 bit integer expressing the sample time in
nanoseconds, to struct <CODE
CLASS="STRUCTNAME"
>timeval</CODE
>. With the
addition of a second memory mapping method the
<CODE
CLASS="STRUCTFIELD"
>offset</CODE
> field moved into union
<CODE
CLASS="STRUCTFIELD"
>m</CODE
>, and a new
<CODE
CLASS="STRUCTFIELD"
>memory</CODE
> field of type enum&nbsp;<A
HREF="x5953.htm#V4L2-MEMORY"
>v4l2_memory</A
> was
added to distinguish between I/O methods. See <A
HREF="c5742.htm"
>Chapter 3</A
>
for details.</P
><P
>The <CODE
CLASS="CONSTANT"
>V4L2_BUF_REQ_CONTIG</CODE
>
flag was used by the V4L compatibility layer, after changes to this
code it was no longer needed. The
<CODE
CLASS="CONSTANT"
>V4L2_BUF_ATTR_DEVICEMEM</CODE
> flag would indicate if
the buffer was indeed allocated in device memory rather than DMA-able
system memory. It was barely useful and so was removed.</P
></LI
><LI
><P
>In struct&nbsp;<A
HREF="r10595.htm#V4L2-FRAMEBUFFER"
>v4l2_framebuffer</A
> the
<CODE
CLASS="STRUCTFIELD"
>base[3]</CODE
> array anticipating double- and
triple-buffering in off-screen video memory, however without defining
a synchronization mechanism, was replaced by a single pointer. The
<CODE
CLASS="CONSTANT"
>V4L2_FBUF_CAP_SCALEUP</CODE
> and
<CODE
CLASS="CONSTANT"
>V4L2_FBUF_CAP_SCALEDOWN</CODE
> flags were removed.
Applications can determine this capability more accurately using the
new cropping and scaling interface. The
<CODE
CLASS="CONSTANT"
>V4L2_FBUF_CAP_CLIPPING</CODE
> flag was replaced by
<CODE
CLASS="CONSTANT"
>V4L2_FBUF_CAP_LIST_CLIPPING</CODE
> and
<CODE
CLASS="CONSTANT"
>V4L2_FBUF_CAP_BITMAP_CLIPPING</CODE
>.</P
></LI
><LI
><P
>In struct&nbsp;<A
HREF="x6570.htm#V4L2-CLIP"
>v4l2_clip</A
> the <CODE
CLASS="STRUCTFIELD"
>x</CODE
>,
<CODE
CLASS="STRUCTFIELD"
>y</CODE
>, <CODE
CLASS="STRUCTFIELD"
>width</CODE
> and
<CODE
CLASS="STRUCTFIELD"
>height</CODE
> field moved into a
<CODE
CLASS="STRUCTFIELD"
>c</CODE
> substructure of type struct&nbsp;<A
HREF="x6570.htm#V4L2-RECT"
>v4l2_rect</A
>. The
<CODE
CLASS="STRUCTFIELD"
>x</CODE
> and <CODE
CLASS="STRUCTFIELD"
>y</CODE
> fields
were renamed to <CODE
CLASS="STRUCTFIELD"
>left</CODE
> and
<CODE
CLASS="STRUCTFIELD"
>top</CODE
>, i.&nbsp;e. offsets to a context dependent
origin.</P
></LI
><LI
><P
>In struct&nbsp;<A
HREF="x6570.htm#V4L2-WINDOW"
>v4l2_window</A
> the <CODE
CLASS="STRUCTFIELD"
>x</CODE
>,
<CODE
CLASS="STRUCTFIELD"
>y</CODE
>, <CODE
CLASS="STRUCTFIELD"
>width</CODE
> and
<CODE
CLASS="STRUCTFIELD"
>height</CODE
> field moved into a
<CODE
CLASS="STRUCTFIELD"
>w</CODE
> substructure as above. A
<CODE
CLASS="STRUCTFIELD"
>field</CODE
> field of type %v4l2-field; was added
to distinguish between field and frame (interlaced) overlay.</P
></LI
><LI
><P
>The digital zoom interface, including struct
<CODE
CLASS="STRUCTNAME"
>v4l2_zoomcap</CODE
>, struct
<CODE
CLASS="STRUCTNAME"
>v4l2_zoom</CODE
>,
<CODE
CLASS="CONSTANT"
>V4L2_ZOOM_NONCAP</CODE
> and
<CODE
CLASS="CONSTANT"
>V4L2_ZOOM_WHILESTREAMING</CODE
> was replaced by a new
cropping and scaling interface. The previously unused struct
<CODE
CLASS="STRUCTNAME"
>v4l2_cropcap</CODE
> and
<CODE
CLASS="STRUCTNAME"
>v4l2_crop</CODE
> where redefined for this purpose.
See <A
HREF="x1904.htm"
>Section 1.11</A
> for details.</P
></LI
><LI
><P
>In struct&nbsp;<A
HREF="x7013.htm#V4L2-VBI-FORMAT"
>v4l2_vbi_format</A
> the
<CODE
CLASS="STRUCTFIELD"
>SAMPLE_FORMAT</CODE
> field now contains a
four-character-code as used to identify video image formats and
<CODE
CLASS="CONSTANT"
>V4L2_PIX_FMT_GREY</CODE
> replaces the
<CODE
CLASS="CONSTANT"
>V4L2_VBI_SF_UBYTE</CODE
> define. The
<CODE
CLASS="STRUCTFIELD"
>reserved</CODE
> field was extended.</P
></LI
><LI
><P
>In struct&nbsp;<A
HREF="r11680.htm#V4L2-CAPTUREPARM"
>v4l2_captureparm</A
> the type of the
<CODE
CLASS="STRUCTFIELD"
>timeperframe</CODE
> field changed from unsigned
long to struct&nbsp;<A
HREF="r9288.htm#V4L2-FRACT"
>v4l2_fract</A
>. This allows the accurate expression of multiples
of the NTSC-M frame rate 30000 / 1001. A new field
<CODE
CLASS="STRUCTFIELD"
>readbuffers</CODE
> was added to control the driver
behaviour in read I/O mode.</P
><P
>Similar changes were made to struct&nbsp;<A
HREF="r11680.htm#V4L2-OUTPUTPARM"
>v4l2_outputparm</A
>.</P
></LI
><LI
><P
>The struct <CODE
CLASS="STRUCTNAME"
>v4l2_performance</CODE
>
and <CODE
CLASS="CONSTANT"
>VIDIOC_G_PERF</CODE
> ioctl were dropped. Except when
using the <A
HREF="c5742.htm#RW"
>read/write I/O method</A
>, which is
limited anyway, this information is already available to
applications.</P
></LI
><LI
><P
>The example transformation from RGB to YCbCr color
space in the old V4L2 documentation was inaccurate, this has been
corrected in <A
HREF="c2030.htm"
>Chapter 2</A
>.</P
></LI
></OL
></DIV
><DIV
CLASS="SECTION"
><H2
CLASS="SECTION"
><A
NAME="AEN16046"
>6.2.10. V4L2 2003-06-19</A
></H2
><P
></P
><OL
TYPE="1"
><LI
><P
>A new capability flag
<CODE
CLASS="CONSTANT"
>V4L2_CAP_RADIO</CODE
> was added for radio devices. Prior
to this change radio devices would identify solely by having exactly one
tuner whose type field reads <CODE
CLASS="CONSTANT"
>V4L2_TUNER_RADIO</CODE
>.</P
></LI
><LI
><P
>An optional driver access priority mechanism was
added, see <A
HREF="x294.htm"
>Section 1.3</A
> for details.</P
></LI
><LI
><P
>The audio input and output interface was found to be
incomplete.</P
><P
>Previously the <A
HREF="r9539.htm"
><CODE
CLASS="CONSTANT"
>VIDIOC_G_AUDIO</CODE
></A
>
ioctl would enumerate the available audio inputs. An ioctl to
determine the current audio input, if more than one combines with the
current video input, did not exist. So
<CODE
CLASS="CONSTANT"
>VIDIOC_G_AUDIO</CODE
> was renamed to
<CODE
CLASS="CONSTANT"
>VIDIOC_G_AUDIO_OLD</CODE
>, this ioctl will be removed in
the future. The <A
HREF="r8242.htm"
><CODE
CLASS="CONSTANT"
>VIDIOC_ENUMAUDIO</CODE
></A
> ioctl was added to enumerate
audio inputs, while <A
HREF="r9539.htm"
><CODE
CLASS="CONSTANT"
>VIDIOC_G_AUDIO</CODE
></A
> now reports the current audio
input.</P
><P
>The same changes were made to <A
HREF="r9688.htm"
><CODE
CLASS="CONSTANT"
>VIDIOC_G_AUDOUT</CODE
></A
> and
<A
HREF="r8304.htm"
><CODE
CLASS="CONSTANT"
>VIDIOC_ENUMAUDOUT</CODE
></A
>.</P
><P
>Until further the "videodev" module will automatically
translate between the old and new ioctls, but drivers and applications
must be updated to successfully compile again.</P
></LI
><LI
><P
>The <A
HREF="r12816.htm"
><CODE
CLASS="CONSTANT"
>VIDIOC_OVERLAY</CODE
></A
> ioctl was incorrectly defined with
write-read parameter. It was changed to write-only, while the write-read
version was renamed to <CODE
CLASS="CONSTANT"
>VIDIOC_OVERLAY_OLD</CODE
>. The old
ioctl will be removed in the future. Until further the "videodev"
kernel module will automatically translate to the new version, so drivers
must be recompiled, but not applications.</P
></LI
><LI
><P
><A
HREF="x6570.htm"
>Section 4.2</A
> incorrectly stated that
clipping rectangles define regions where the video can be seen.
Correct is that clipping rectangles define regions where
<SPAN
CLASS="emphasis"
><I
CLASS="EMPHASIS"
>no</I
></SPAN
> video shall be displayed and so the graphics
surface can be seen.</P
></LI
><LI
><P
>The <A
HREF="r11680.htm"
><CODE
CLASS="CONSTANT"
>VIDIOC_S_PARM</CODE
></A
> and <A
HREF="r10104.htm"
><CODE
CLASS="CONSTANT"
>VIDIOC_S_CTRL</CODE
></A
> ioctls were
defined with write-only parameter, inconsistent with other ioctls
modifying their argument. They were changed to write-read, while a
<CODE
CLASS="CONSTANT"
>_OLD</CODE
> suffix was added to the write-only versions.
The old ioctls will be removed in the future. Drivers and
applications assuming a constant parameter need an update.</P
></LI
></OL
></DIV
><DIV
CLASS="SECTION"
><H2
CLASS="SECTION"
><A
NAME="AEN16089"
>6.2.11. V4L2 2003-11-05</A
></H2
><P
></P
><OL
TYPE="1"
><LI
><P
>In <A
HREF="x2490.htm"
>Section 2.4</A
> the following pixel
formats were incorrectly transferred from Bill Dirks' V4L2
specification. Descriptions below refer to bytes in memory, in
ascending address order.<DIV
CLASS="INFORMALTABLE"
><P
></P
><A
NAME="AEN16095"
></A
><TABLE
BORDER="1"
CLASS="CALSTABLE"
><COL><COL><COL><THEAD
><TR
><TH
>Symbol</TH
><TH
>In this document prior to revision
0.5</TH
><TH
>Corrected</TH
></TR
></THEAD
><TBODY
VALIGN="TOP"
><TR
><TD
><CODE
CLASS="CONSTANT"
>V4L2_PIX_FMT_RGB24</CODE
></TD
><TD
>B, G, R</TD
><TD
>R, G, B</TD
></TR
><TR
><TD
><CODE
CLASS="CONSTANT"
>V4L2_PIX_FMT_BGR24</CODE
></TD
><TD
>R, G, B</TD
><TD
>B, G, R</TD
></TR
><TR
><TD
><CODE
CLASS="CONSTANT"
>V4L2_PIX_FMT_RGB32</CODE
></TD
><TD
>B, G, R, X</TD
><TD
>R, G, B, X</TD
></TR
><TR
><TD
><CODE
CLASS="CONSTANT"
>V4L2_PIX_FMT_BGR32</CODE
></TD
><TD
>R, G, B, X</TD
><TD
>B, G, R, X</TD
></TR
></TBODY
></TABLE
><P
></P
></DIV
> The
<CODE
CLASS="CONSTANT"
>V4L2_PIX_FMT_BGR24</CODE
> example was always
correct.</P
><P
>In <A
HREF="c14595.htm#V4L-IMAGE-PROPERTIES"
>Section 6.1.5</A
> the mapping
of the V4L <CODE
CLASS="CONSTANT"
>VIDEO_PALETTE_RGB24</CODE
> and
<CODE
CLASS="CONSTANT"
>VIDEO_PALETTE_RGB32</CODE
> formats to V4L2 pixel formats
was accordingly corrected.</P
></LI
><LI
><P
>Unrelated to the fixes above, drivers may still
interpret some V4L2 RGB pixel formats differently. These issues have
yet to be addressed, for details see <A
HREF="x2490.htm"
>Section 2.4</A
>.</P
></LI
></OL
></DIV
><DIV
CLASS="SECTION"
><H2
CLASS="SECTION"
><A
NAME="AEN16131"
>6.2.12. V4L2 in Linux 2.6.6, 2004-05-09</A
></H2
><P
></P
><OL
TYPE="1"
><LI
><P
>The <A
HREF="r7771.htm"
><CODE
CLASS="CONSTANT"
>VIDIOC_CROPCAP</CODE
></A
> ioctl was incorrectly defined
with read-only parameter. It is now defined as write-read ioctl, while
the read-only version was renamed to
<CODE
CLASS="CONSTANT"
>VIDIOC_CROPCAP_OLD</CODE
>. The old ioctl will be removed
in the future.</P
></LI
></OL
></DIV
><DIV
CLASS="SECTION"
><H2
CLASS="SECTION"
><A
NAME="AEN16139"
>6.2.13. V4L2 in Linux 2.6.8</A
></H2
><P
></P
><OL
TYPE="1"
><LI
><P
>A new field <CODE
CLASS="STRUCTFIELD"
>input</CODE
> (former
<CODE
CLASS="STRUCTFIELD"
>reserved[0]</CODE
>) was added to the struct&nbsp;<A
HREF="x5953.htm#V4L2-BUFFER"
>v4l2_buffer</A
>
structure. Purpose of this field is to alternate between video inputs
(e.&nbsp;g. cameras) in step with the video capturing process. This function
must be enabled with the new <CODE
CLASS="CONSTANT"
>V4L2_BUF_FLAG_INPUT</CODE
>
flag. The <CODE
CLASS="STRUCTFIELD"
>flags</CODE
> field is no longer
read-only.</P
></LI
></OL
></DIV
><DIV
CLASS="SECTION"
><H2
CLASS="SECTION"
><A
NAME="AEN16149"
>6.2.14. V4L2 spec erratum 2004-08-01</A
></H2
><P
></P
><OL
TYPE="1"
><LI
><P
>The return value of the
<A
HREF="r14090.htm"
>V4L2 open()(2)</A
> function was incorrectly documented.</P
></LI
><LI
><P
>Audio output ioctls end in -AUDOUT, not -AUDIOOUT.</P
></LI
><LI
><P
>In the Current Audio Input example the
<CODE
CLASS="CONSTANT"
>VIDIOC_G_AUDIO</CODE
> ioctl took the wrong
argument.</P
></LI
><LI
><P
>The documentation of the <A
HREF="r12878.htm"
><CODE
CLASS="CONSTANT"
>VIDIOC_QBUF</CODE
></A
> and
<A
HREF="r12878.htm"
><CODE
CLASS="CONSTANT"
>VIDIOC_DQBUF</CODE
></A
> ioctls did not mention the struct&nbsp;<A
HREF="x5953.htm#V4L2-BUFFER"
>v4l2_buffer</A
>
<CODE
CLASS="STRUCTFIELD"
>memory</CODE
> field. It was also missing from
examples. Also on the <CODE
CLASS="CONSTANT"
>VIDIOC_DQBUF</CODE
> page the <SPAN
CLASS="ERRORCODE"
>EIO</SPAN
> error code
was not documented.</P
></LI
></OL
></DIV
><DIV
CLASS="SECTION"
><H2
CLASS="SECTION"
><A
NAME="AEN16170"
>6.2.15. V4L2 in Linux 2.6.14</A
></H2
><P
></P
><OL
TYPE="1"
><LI
><P
>A new sliced VBI interface was added. It is documented
in <A
HREF="x7236.htm"
>Section 4.8</A
> and replaces the interface first
proposed in V4L2 specification 0.8.</P
></LI
></OL
></DIV
><DIV
CLASS="SECTION"
><H2
CLASS="SECTION"
><A
NAME="AEN16176"
>6.2.16. V4L2 in Linux 2.6.15</A
></H2
><P
></P
><OL
TYPE="1"
><LI
><P
>The <A
HREF="r12784.htm"
><CODE
CLASS="CONSTANT"
>VIDIOC_LOG_STATUS</CODE
></A
> ioctl was added.</P
></LI
><LI
><P
>New video standards
<CODE
CLASS="CONSTANT"
>V4L2_STD_NTSC_443</CODE
>,
<CODE
CLASS="CONSTANT"
>V4L2_STD_SECAM_LC</CODE
>,
<CODE
CLASS="CONSTANT"
>V4L2_STD_SECAM_DK</CODE
> (a set of SECAM D, K and K1),
and <CODE
CLASS="CONSTANT"
>V4L2_STD_ATSC</CODE
> (a set of
<CODE
CLASS="CONSTANT"
>V4L2_STD_ATSC_8_VSB</CODE
> and
<CODE
CLASS="CONSTANT"
>V4L2_STD_ATSC_16_VSB</CODE
>) were defined. Note the
<CODE
CLASS="CONSTANT"
>V4L2_STD_525_60</CODE
> set now includes
<CODE
CLASS="CONSTANT"
>V4L2_STD_NTSC_443</CODE
>. See also <A
HREF="r9288.htm#V4L2-STD-ID"
>Table 3</A
>.</P
></LI
><LI
><P
>The <CODE
CLASS="CONSTANT"
>VIDIOC_G_COMP</CODE
> and
<CODE
CLASS="CONSTANT"
>VIDIOC_S_COMP</CODE
> ioctl were renamed to
<CODE
CLASS="CONSTANT"
>VIDIOC_G_MPEGCOMP</CODE
> and
<CODE
CLASS="CONSTANT"
>VIDIOC_S_MPEGCOMP</CODE
> respectively. Their argument
was replaced by a struct
<CODE
CLASS="STRUCTNAME"
>v4l2_mpeg_compression</CODE
> pointer. (The
<CODE
CLASS="CONSTANT"
>VIDIOC_G_MPEGCOMP</CODE
> and
<CODE
CLASS="CONSTANT"
>VIDIOC_S_MPEGCOMP</CODE
> ioctls where removed in Linux
2.6.25.)</P
></LI
></OL
></DIV
><DIV
CLASS="SECTION"
><H2
CLASS="SECTION"
><A
NAME="AEN16203"
>6.2.17. V4L2 spec erratum 2005-11-27</A
></H2
><P
>The capture example in <A
HREF="a16706.htm"
>Appendix B</A
>
called the <A
HREF="r9994.htm"
><CODE
CLASS="CONSTANT"
>VIDIOC_S_CROP</CODE
></A
> ioctl without checking if cropping is
supported. In the video standard selection example in
<A
HREF="x448.htm"
>Section 1.7</A
> the <A
HREF="r12265.htm"
><CODE
CLASS="CONSTANT"
>VIDIOC_S_STD</CODE
></A
> call used the wrong
argument type.</P
></DIV
><DIV
CLASS="SECTION"
><H2
CLASS="SECTION"
><A
NAME="AEN16212"
>6.2.18. V4L2 spec erratum 2006-01-10</A
></H2
><P
></P
><OL
TYPE="1"
><LI
><P
>The <CODE
CLASS="CONSTANT"
>V4L2_IN_ST_COLOR_KILL</CODE
> flag in
struct&nbsp;<A
HREF="r8936.htm#V4L2-INPUT"
>v4l2_input</A
> not only indicates if the color killer is enabled, but
also if it is active. (The color killer disables color decoding when
it detects no color in the video signal to improve the image
quality.)</P
></LI
><LI
><P
><A
HREF="r11680.htm"
><CODE
CLASS="CONSTANT"
>VIDIOC_S_PARM</CODE
></A
> is a write-read ioctl, not write-only as
stated on its reference page. The ioctl changed in 2003 as noted above.</P
></LI
></OL
></DIV
><DIV
CLASS="SECTION"
><H2
CLASS="SECTION"
><A
NAME="AEN16223"
>6.2.19. V4L2 spec erratum 2006-02-03</A
></H2
><P
></P
><OL
TYPE="1"
><LI
><P
>In struct&nbsp;<A
HREF="r11680.htm#V4L2-CAPTUREPARM"
>v4l2_captureparm</A
> and struct&nbsp;<A
HREF="r11680.htm#V4L2-OUTPUTPARM"
>v4l2_outputparm</A
> the
<CODE
CLASS="STRUCTFIELD"
>timeperframe</CODE
> field gives the time in
seconds, not microseconds.</P
></LI
></OL
></DIV
><DIV
CLASS="SECTION"
><H2
CLASS="SECTION"
><A
NAME="AEN16231"
>6.2.20. V4L2 spec erratum 2006-02-04</A
></H2
><P
></P
><OL
TYPE="1"
><LI
><P
>The <CODE
CLASS="STRUCTFIELD"
>clips</CODE
> field in
struct&nbsp;<A
HREF="x6570.htm#V4L2-WINDOW"
>v4l2_window</A
> must point to an array of struct&nbsp;<A
HREF="x6570.htm#V4L2-CLIP"
>v4l2_clip</A
>, not a linked
list, because drivers ignore the struct
<CODE
CLASS="STRUCTNAME"
>v4l2_clip</CODE
>.<CODE
CLASS="STRUCTFIELD"
>next</CODE
>
pointer.</P
></LI
></OL
></DIV
><DIV
CLASS="SECTION"
><H2
CLASS="SECTION"
><A
NAME="AEN16241"
>6.2.21. V4L2 in Linux 2.6.17</A
></H2
><P
></P
><OL
TYPE="1"
><LI
><P
>New video standard macros were added:
<CODE
CLASS="CONSTANT"
>V4L2_STD_NTSC_M_KR</CODE
> (NTSC M South Korea), and the
sets <CODE
CLASS="CONSTANT"
>V4L2_STD_MN</CODE
>,
<CODE
CLASS="CONSTANT"
>V4L2_STD_B</CODE
>, <CODE
CLASS="CONSTANT"
>V4L2_STD_GH</CODE
> and
<CODE
CLASS="CONSTANT"
>V4L2_STD_DK</CODE
>. The
<CODE
CLASS="CONSTANT"
>V4L2_STD_NTSC</CODE
> and
<CODE
CLASS="CONSTANT"
>V4L2_STD_SECAM</CODE
> sets now include
<CODE
CLASS="CONSTANT"
>V4L2_STD_NTSC_M_KR</CODE
> and
<CODE
CLASS="CONSTANT"
>V4L2_STD_SECAM_LC</CODE
> respectively.</P
></LI
><LI
><P
>A new <CODE
CLASS="CONSTANT"
>V4L2_TUNER_MODE_LANG1_LANG2</CODE
>
was defined to record both languages of a bilingual program. The
use of <CODE
CLASS="CONSTANT"
>V4L2_TUNER_MODE_STEREO</CODE
> for this purpose
is deprecated now. See the <A
HREF="r12342.htm"
><CODE
CLASS="CONSTANT"
>VIDIOC_G_TUNER</CODE
></A
> section for
details.</P
></LI
></OL
></DIV
><DIV
CLASS="SECTION"
><H2
CLASS="SECTION"
><A
NAME="AEN16261"
>6.2.22. V4L2 spec erratum 2006-09-23 (Draft 0.15)</A
></H2
><P
></P
><OL
TYPE="1"
><LI
><P
>In various places
<CODE
CLASS="CONSTANT"
>V4L2_BUF_TYPE_SLICED_VBI_CAPTURE</CODE
> and
<CODE
CLASS="CONSTANT"
>V4L2_BUF_TYPE_SLICED_VBI_OUTPUT</CODE
> of the sliced VBI
interface were not mentioned along with other buffer types.</P
></LI
><LI
><P
>In <A
HREF="r9539.htm"
>ioctl VIDIOC_G_AUDIO, VIDIOC_S_AUDIO(2)</A
> it was clarified
that the struct&nbsp;<A
HREF="r9539.htm#V4L2-AUDIO"
>v4l2_audio</A
> <CODE
CLASS="STRUCTFIELD"
>mode</CODE
> field is a flags
field.</P
></LI
><LI
><P
><A
HREF="r13105.htm"
>ioctl VIDIOC_QUERYCAP(2)</A
> did not mention the
sliced VBI and radio capability flags.</P
></LI
><LI
><P
>In <A
HREF="r11094.htm"
>ioctl VIDIOC_G_FREQUENCY, VIDIOC_S_FREQUENCY(2)</A
> it was
clarified that applications must initialize the tuner
<CODE
CLASS="STRUCTFIELD"
>type</CODE
> field of struct&nbsp;<A
HREF="r11094.htm#V4L2-FREQUENCY"
>v4l2_frequency</A
> before
calling <A
HREF="r11094.htm"
><CODE
CLASS="CONSTANT"
>VIDIOC_S_FREQUENCY</CODE
></A
>.</P
></LI
><LI
><P
>The <CODE
CLASS="STRUCTFIELD"
>reserved</CODE
> array
in struct&nbsp;<A
HREF="r13696.htm#V4L2-REQUESTBUFFERS"
>v4l2_requestbuffers</A
> has 2 elements, not 32.</P
></LI
><LI
><P
>In <A
HREF="x6831.htm"
>Section 4.3</A
> and <A
HREF="x7013.htm"
>Section 4.7</A
> the device file names
<TT
CLASS="FILENAME"
>/dev/vout</TT
> which never caught on were replaced
by <TT
CLASS="FILENAME"
>/dev/video</TT
>.</P
></LI
><LI
><P
>With Linux 2.6.15 the possible range for VBI device minor
numbers was extended from 224-239 to 224-255. Accordingly device file names
<TT
CLASS="FILENAME"
>/dev/vbi0</TT
> to <TT
CLASS="FILENAME"
>/dev/vbi31</TT
> are
possible now.</P
></LI
></OL
></DIV
><DIV
CLASS="SECTION"
><H2
CLASS="SECTION"
><A
NAME="AEN16297"
>6.2.23. V4L2 in Linux 2.6.18</A
></H2
><P
></P
><OL
TYPE="1"
><LI
><P
>New ioctls <A
HREF="r10386.htm"
><CODE
CLASS="CONSTANT"
>VIDIOC_G_EXT_CTRLS</CODE
></A
>, <A
HREF="r10386.htm"
><CODE
CLASS="CONSTANT"
>VIDIOC_S_EXT_CTRLS</CODE
></A
>
and <A
HREF="r10386.htm"
><CODE
CLASS="CONSTANT"
>VIDIOC_TRY_EXT_CTRLS</CODE
></A
> were added, a flag to skip unsupported
controls with <A
HREF="r13317.htm"
><CODE
CLASS="CONSTANT"
>VIDIOC_QUERYCTRL</CODE
></A
>, new control types
<CODE
CLASS="CONSTANT"
>V4L2_CTRL_TYPE_INTEGER64</CODE
> and
<CODE
CLASS="CONSTANT"
>V4L2_CTRL_TYPE_CTRL_CLASS</CODE
> (<A
HREF="r13317.htm#V4L2-CTRL-TYPE"
>Table 3</A
>), and new control flags
<CODE
CLASS="CONSTANT"
>V4L2_CTRL_FLAG_READ_ONLY</CODE
>,
<CODE
CLASS="CONSTANT"
>V4L2_CTRL_FLAG_UPDATE</CODE
>,
<CODE
CLASS="CONSTANT"
>V4L2_CTRL_FLAG_INACTIVE</CODE
> and
<CODE
CLASS="CONSTANT"
>V4L2_CTRL_FLAG_SLIDER</CODE
> (<A
HREF="r13317.htm#CONTROL-FLAGS"
>Table 4</A
>). See <A
HREF="x802.htm"
>Section 1.9</A
> for details.</P
></LI
></OL
></DIV
><DIV
CLASS="SECTION"
><H2
CLASS="SECTION"
><A
NAME="AEN16319"
>6.2.24. V4L2 in Linux 2.6.19</A
></H2
><P
></P
><OL
TYPE="1"
><LI
><P
>In struct&nbsp;<A
HREF="r12051.htm#V4L2-SLICED-VBI-CAP"
>v4l2_sliced_vbi_cap</A
> a buffer type field was added
replacing a reserved field. Note on architectures where the size of
enum types differs from int types the size of the structure changed.
The <A
HREF="r12051.htm"
><CODE
CLASS="CONSTANT"
>VIDIOC_G_SLICED_VBI_CAP</CODE
></A
> ioctl was redefined from being read-only
to write-read. Applications must initialize the type field and clear
the reserved fields now. These changes may <SPAN
CLASS="emphasis"
><I
CLASS="EMPHASIS"
>break the
compatibility</I
></SPAN
> with older drivers and applications.</P
></LI
><LI
><P
>The ioctls <A
HREF="r8494.htm"
><CODE
CLASS="CONSTANT"
>VIDIOC_ENUM_FRAMESIZES</CODE
></A
> and
<A
HREF="r8724.htm"
><CODE
CLASS="CONSTANT"
>VIDIOC_ENUM_FRAMEINTERVALS</CODE
></A
> were added.</P
></LI
><LI
><P
>A new pixel format <CODE
CLASS="CONSTANT"
>V4L2_PIX_FMT_RGB444</CODE
> (<A
HREF="r2492.htm#RGB-FORMATS"
>Table 2-1</A
>) was added.</P
></LI
></OL
></DIV
><DIV
CLASS="SECTION"
><H2
CLASS="SECTION"
><A
NAME="AEN16338"
>6.2.25. V4L2 spec erratum 2006-10-12 (Draft 0.17)</A
></H2
><P
></P
><OL
TYPE="1"
><LI
><P
><CODE
CLASS="CONSTANT"
>V4L2_PIX_FMT_HM12</CODE
> (<A
HREF="x5665.htm#RESERVED-FORMATS"
>Table 2-8</A
>) is a YUV 4:2:0, not 4:2:2 format.</P
></LI
></OL
></DIV
><DIV
CLASS="SECTION"
><H2
CLASS="SECTION"
><A
NAME="AEN16345"
>6.2.26. V4L2 in Linux 2.6.21</A
></H2
><P
></P
><OL
TYPE="1"
><LI
><P
>The <TT
CLASS="FILENAME"
>videodev2.h</TT
> header file is
now dual licensed under GNU General Public License version two or
later, and under a 3-clause BSD-style license.</P
></LI
></OL
></DIV
><DIV
CLASS="SECTION"
><H2
CLASS="SECTION"
><A
NAME="AEN16351"
>6.2.27. V4L2 in Linux 2.6.22</A
></H2
><P
></P
><OL
TYPE="1"
><LI
><P
>Two new field orders
<CODE
CLASS="CONSTANT"
>V4L2_FIELD_INTERLACED_TB</CODE
> and
<CODE
CLASS="CONSTANT"
>V4L2_FIELD_INTERLACED_BT</CODE
> were
added. See <A
HREF="x6386.htm#V4L2-FIELD"
>Table 3-8</A
> for details.</P
></LI
><LI
><P
>Three new clipping/blending methods with a global or
straight or inverted local alpha value were added to the video overlay
interface. See the description of the <A
HREF="r10595.htm"
><CODE
CLASS="CONSTANT"
>VIDIOC_G_FBUF</CODE
></A
> and
<A
HREF="r10595.htm"
><CODE
CLASS="CONSTANT"
>VIDIOC_S_FBUF</CODE
></A
> ioctls for details.</P
><P
>A new <CODE
CLASS="STRUCTFIELD"
>global_alpha</CODE
> field
was added to <A
HREF="x6570.htm#V4L2-WINDOW"
><CODE
CLASS="STRUCTNAME"
>v4l2_window</CODE
></A
>,
extending the structure. This may <SPAN
CLASS="emphasis"
><I
CLASS="EMPHASIS"
>break
compatibility</I
></SPAN
> with applications using a struct
<CODE
CLASS="STRUCTNAME"
>v4l2_window</CODE
> directly. However the <A
HREF="r10944.htm"
>VIDIOC_G/S/TRY_FMT</A
> ioctls, which take a
pointer to a <A
HREF="r10944.htm#V4L2-FORMAT"
>v4l2_format</A
> parent
structure with padding bytes at the end, are not affected.</P
></LI
><LI
><P
>The format of the <CODE
CLASS="STRUCTFIELD"
>chromakey</CODE
>
field in struct&nbsp;<A
HREF="x6570.htm#V4L2-WINDOW"
>v4l2_window</A
> changed from "host order RGB32" to a pixel
value in the same format as the framebuffer. This may <SPAN
CLASS="emphasis"
><I
CLASS="EMPHASIS"
>break
compatibility</I
></SPAN
> with existing applications. Drivers
supporting the "host order RGB32" format are not known.</P
></LI
></OL
></DIV
><DIV
CLASS="SECTION"
><H2
CLASS="SECTION"
><A
NAME="AEN16378"
>6.2.28. V4L2 in Linux 2.6.24</A
></H2
><P
></P
><OL
TYPE="1"
><LI
><P
>The pixel formats
<CODE
CLASS="CONSTANT"
>V4L2_PIX_FMT_PAL8</CODE
>,
<CODE
CLASS="CONSTANT"
>V4L2_PIX_FMT_YUV444</CODE
>,
<CODE
CLASS="CONSTANT"
>V4L2_PIX_FMT_YUV555</CODE
>,
<CODE
CLASS="CONSTANT"
>V4L2_PIX_FMT_YUV565</CODE
> and
<CODE
CLASS="CONSTANT"
>V4L2_PIX_FMT_YUV32</CODE
> were added.</P
></LI
></OL
></DIV
><DIV
CLASS="SECTION"
><H2
CLASS="SECTION"
><A
NAME="AEN16388"
>6.2.29. V4L2 in Linux 2.6.25</A
></H2
><P
></P
><OL
TYPE="1"
><LI
><P
>The pixel formats <A
HREF="r4246.htm"
><CODE
CLASS="CONSTANT"
>V4L2_PIX_FMT_Y16</CODE
></A
> and <A
HREF="r3796.htm"
><CODE
CLASS="CONSTANT"
>V4L2_PIX_FMT_SBGGR16</CODE
></A
> were added.</P
></LI
><LI
><P
>New <A
HREF="x542.htm"
>controls</A
>
<CODE
CLASS="CONSTANT"
>V4L2_CID_POWER_LINE_FREQUENCY</CODE
>,
<CODE
CLASS="CONSTANT"
>V4L2_CID_HUE_AUTO</CODE
>,
<CODE
CLASS="CONSTANT"
>V4L2_CID_WHITE_BALANCE_TEMPERATURE</CODE
>,
<CODE
CLASS="CONSTANT"
>V4L2_CID_SHARPNESS</CODE
> and
<CODE
CLASS="CONSTANT"
>V4L2_CID_BACKLIGHT_COMPENSATION</CODE
> were added. The
controls <CODE
CLASS="CONSTANT"
>V4L2_CID_BLACK_LEVEL</CODE
>,
<CODE
CLASS="CONSTANT"
>V4L2_CID_WHITENESS</CODE
>,
<CODE
CLASS="CONSTANT"
>V4L2_CID_HCENTER</CODE
> and
<CODE
CLASS="CONSTANT"
>V4L2_CID_VCENTER</CODE
> were deprecated.</P
></LI
><LI
><P
>A <A
HREF="x802.htm#CAMERA-CONTROLS"
>Camera controls
class</A
> was added, with the new controls
<CODE
CLASS="CONSTANT"
>V4L2_CID_EXPOSURE_AUTO</CODE
>,
<CODE
CLASS="CONSTANT"
>V4L2_CID_EXPOSURE_ABSOLUTE</CODE
>,
<CODE
CLASS="CONSTANT"
>V4L2_CID_EXPOSURE_AUTO_PRIORITY</CODE
>,
<CODE
CLASS="CONSTANT"
>V4L2_CID_PAN_RELATIVE</CODE
>,
<CODE
CLASS="CONSTANT"
>V4L2_CID_TILT_RELATIVE</CODE
>,
<CODE
CLASS="CONSTANT"
>V4L2_CID_PAN_RESET</CODE
>,
<CODE
CLASS="CONSTANT"
>V4L2_CID_TILT_RESET</CODE
>,
<CODE
CLASS="CONSTANT"
>V4L2_CID_PAN_ABSOLUTE</CODE
>,
<CODE
CLASS="CONSTANT"
>V4L2_CID_TILT_ABSOLUTE</CODE
>,
<CODE
CLASS="CONSTANT"
>V4L2_CID_FOCUS_ABSOLUTE</CODE
>,
<CODE
CLASS="CONSTANT"
>V4L2_CID_FOCUS_RELATIVE</CODE
> and
<CODE
CLASS="CONSTANT"
>V4L2_CID_FOCUS_AUTO</CODE
>.</P
></LI
><LI
><P
>The <CODE
CLASS="CONSTANT"
>VIDIOC_G_MPEGCOMP</CODE
> and
<CODE
CLASS="CONSTANT"
>VIDIOC_S_MPEGCOMP</CODE
> ioctls, which were superseded
by the <A
HREF="x802.htm"
>extended controls</A
>
interface in Linux 2.6.18, where finally removed from the
<TT
CLASS="FILENAME"
>videodev2.h</TT
> header file.</P
></LI
></OL
></DIV
></DIV
><DIV
CLASS="NAVFOOTER"
><HR
ALIGN="LEFT"
WIDTH="100%"><TABLE
SUMMARY="Footer navigation table"
WIDTH="100%"
BORDER="0"
CELLPADDING="0"
CELLSPACING="0"
><TR
><TD
WIDTH="33%"
ALIGN="left"
VALIGN="top"
><A
HREF="c14595.htm"
ACCESSKEY="P"
>Prev</A
></TD
><TD
WIDTH="34%"
ALIGN="center"
VALIGN="top"
><A
HREF="book1.htm"
ACCESSKEY="H"
>Home</A
></TD
><TD
WIDTH="33%"
ALIGN="right"
VALIGN="top"
><A
HREF="x16430.htm"
ACCESSKEY="N"
>Next</A
></TD
></TR
><TR
><TD
WIDTH="33%"
ALIGN="left"
VALIGN="top"
>Changes</TD
><TD
WIDTH="34%"
ALIGN="center"
VALIGN="top"
><A
HREF="c14595.htm"
ACCESSKEY="U"
>Up</A
></TD
><TD
WIDTH="33%"
ALIGN="right"
VALIGN="top"
>Relation of V4L2 to other Linux multimedia APIs</TD
></TR
></TABLE
></DIV
></BODY
></HTML
>