[media] Remove compatibility layer from multi-planar API documentation
This feature will probably be moved to libv4l2. Signed-off-by: Pawel Osciak <pawel@osciak.com> Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>
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@ -2,10 +2,10 @@
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<title>Single- and multi-planar APIs</title>
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<para>Some devices require data for each input or output video frame
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to be placed in discontiguous memory buffers. In such cases one
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to be placed in discontiguous memory buffers. In such cases, one
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video frame has to be addressed using more than one memory address, i.e. one
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pointer per "plane". A plane is a sub-buffer of current frame. For examples
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of such formats see <xref linkend="pixfmt" />.</para>
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pointer per "plane". A plane is a sub-buffer of the current frame. For
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examples of such formats see <xref linkend="pixfmt" />.</para>
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<para>Initially, V4L2 API did not support multi-planar buffers and a set of
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extensions has been introduced to handle them. Those extensions constitute
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@ -14,8 +14,8 @@
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<para>Some of the V4L2 API calls and structures are interpreted differently,
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depending on whether single- or multi-planar API is being used. An application
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can choose whether to use one or the other by passing a corresponding buffer
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type to its ioctl calls. Multi-planar versions of buffer types are suffixed with
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an `_MPLANE' string. For a list of available multi-planar buffer types
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type to its ioctl calls. Multi-planar versions of buffer types are suffixed
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with an `_MPLANE' string. For a list of available multi-planar buffer types
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see &v4l2-buf-type;.
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</para>
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@ -24,28 +24,9 @@
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<para>Multi-planar API introduces new multi-planar formats. Those formats
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use a separate set of FourCC codes. It is important to distinguish between
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the multi-planar API and a multi-planar format. Multi-planar API calls can
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handle all single-planar formats as well, while the single-planar API cannot
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handle multi-planar formats. Applications do not have to switch between APIs
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when handling both single- and multi-planar devices and should use the
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multi-planar API version for both single- and multi-planar formats.
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Drivers that do not support multi-planar API can still be handled with it,
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utilizing a compatibility layer built into standard V4L2 ioctl handling.
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</para>
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</section>
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<section>
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<title>Single and multi-planar API compatibility layer</title>
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<para>In most cases<footnote><para>The compatibility layer does not cover
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drivers that do not use video_ioctl2() call.</para></footnote>, applications
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can use the multi-planar API with older drivers that support
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only its single-planar version and vice versa. Appropriate conversion is
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done seamlessly for both applications and drivers in the V4L2 core. The
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general rule of thumb is: as long as an application uses formats that
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a driver supports, it can use either API (although use of multi-planar
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formats is only possible with the multi-planar API). The list of formats
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supported by a driver can be obtained using the &VIDIOC-ENUM-FMT; call.
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It is possible, but discouraged, for a driver or an application to support
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and use both versions of the API.</para>
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handle all single-planar formats as well (as long as they are passed in
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multi-planar API structures), while the single-planar API cannot
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handle multi-planar formats.</para>
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</section>
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<section>
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@ -142,30 +142,28 @@ this array to zero.</entry>
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<row>
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<entry><constant>V4L2_CAP_VIDEO_CAPTURE</constant></entry>
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<entry>0x00000001</entry>
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<entry>The device supports single-planar formats through the <link
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linkend="capture">Video Capture</link> interface. An application can use either
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<link linkend="planar-apis">the single or the multi-planar API</link>.</entry>
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<entry>The device supports the single-planar API through the <link
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linkend="capture">Video Capture</link> interface.</entry>
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</row>
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<row>
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<entry><constant>V4L2_CAP_VIDEO_CAPTURE_MPLANE</constant></entry>
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<entry>0x00001000</entry>
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<entry>The device supports multi-planar formats through the <link
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linkend="capture">Video Capture</link> interface. An application has to use the
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<link linkend="planar-apis">multi-planar API</link>.</entry>
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<entry>The device supports the
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<link linkend="planar-apis">multi-planar API</link> through the
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<link linkend="capture">Video Capture</link> interface.</entry>
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</row>
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<row>
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<entry><constant>V4L2_CAP_VIDEO_OUTPUT</constant></entry>
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<entry>0x00000002</entry>
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<entry>The device supports single-planar formats through the <link
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linkend="output">Video Output</link> interface. An application can use either
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<link linkend="planar-apis">the single or the multi-planar API</link>.</entry>
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<entry>The device supports the single-planar API through the <link
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linkend="output">Video Output</link> interface.</entry>
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</row>
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<row>
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<entry><constant>V4L2_CAP_VIDEO_OUTPUT_MPLANE</constant></entry>
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<entry>0x00002000</entry>
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<entry>The device supports multi-planar formats through the <link
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linkend="output">Video Output</link> interface. An application has to use the
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<link linkend="planar-apis">multi-planar API</link>.</entry>
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<entry>The device supports the
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<link linkend="planar-apis">multi-planar API</link> through the
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<link linkend="output">Video Output</link> interface.</entry>
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</row>
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<row>
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<entry><constant>V4L2_CAP_VIDEO_OVERLAY</constant></entry>
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