[media] Add multi-planar API documentation

Add DocBook documentation for the new multi-planar API extensions to the
Video for Linux 2 API DocBook.

Signed-off-by: Pawel Osciak <pawel@osciak.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>
This commit is contained in:
Pawel Osciak
2011-01-07 01:41:33 -03:00
committed by Mauro Carvalho Chehab
parent c4c0a78d45
commit 53b5d5749b
16 changed files with 530 additions and 70 deletions

View File

@@ -61,6 +61,10 @@ buffer at any time after buffers have been allocated with the
to the number of buffers allocated with &VIDIOC-REQBUFS;
(&v4l2-requestbuffers; <structfield>count</structfield>) minus one.
The <structfield>reserved</structfield> field should to set to 0.
When using the <link linkend="planar-apis">multi-planar API</link>, the
<structfield>m.planes</structfield> field must contain a userspace pointer to an
array of &v4l2-plane; and the <structfield>length</structfield> field has
to be set to the number of elements in that array.
After calling <constant>VIDIOC_QUERYBUF</constant> with a pointer to
this structure drivers return an error code or fill the rest of
the structure.</para>
@@ -70,11 +74,13 @@ the structure.</para>
<constant>V4L2_BUF_FLAG_QUEUED</constant> and
<constant>V4L2_BUF_FLAG_DONE</constant> flags will be valid. The
<structfield>memory</structfield> field will be set to the current
I/O method, the <structfield>m.offset</structfield>
I/O method. For the single-planar API, the <structfield>m.offset</structfield>
contains the offset of the buffer from the start of the device memory,
the <structfield>length</structfield> field its size. The driver may
or may not set the remaining fields and flags, they are meaningless in
this context.</para>
the <structfield>length</structfield> field its size. For the multi-planar API,
fields <structfield>m.mem_offset</structfield> and
<structfield>length</structfield> in the <structfield>m.planes</structfield>
array elements will be used instead. The driver may or may not set the remaining
fields and flags, they are meaningless in this context.</para>
<para>The <structname>v4l2_buffer</structname> structure is
specified in <xref linkend="buffer" />.</para>