AuxXxilium/linux_dsm_epyc7002
1
0
Fork 0
mirror of https://github.com/AuxXxilium/linux_dsm_epyc7002.git synced 2024-12-18 18:57:47 +07:00
Code Issues Actions Packages Projects Releases Wiki Activity

media: field-order.rst: clarify FIELD_ANY and FIELD_NONE

Browse Source 
Rephrased the FIELD_ANY description: rather than explicitly list
field values, just say 'when any field format is acceptable'. The
list of FIELD values was outdated, so it was a bit confusing.

The FIELD_NONE description said that 'The driver may also indicate
this order when it cannot distinguish between V4L2_FIELD_TOP and
V4L2_FIELD_BOTTOM'. This is false, NONE really means a full frame
and userspace depends on that. So drop this line completely. There
are no drivers that do this anyway.

FIELD_TOP/BOTTOM/ALTERNATE indicate that the number of lines in the
buffer are that of a field, not frame, so returning NONE here would
cause huge problems.

Finally attempt to clarify 'progressive' and 'interlaced' a little
bit.

Signed-off-by: Hans Verkuil <hverkuil-cisco@xs4all.nl>
Signed-off-by: Mauro Carvalho Chehab <mchehab+samsung@kernel.org>
This commit is contained in:
Hans Verkuil 2019-04-23 10:05:09 -04:00 committed by Mauro Carvalho Chehab
parent 16204b8a1c
commit 823a633eeb
1 changed files with 7 additions and 9 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

16
Documentation/media/uapi/v4l/field-order.rst
View File

@ -75,12 +75,11 @@ enum v4l2_field
* - ``V4L2_FIELD_ANY`` * - ``V4L2_FIELD_ANY``
- 0 - 0
- Applications request this field order when any one of the - Applications request this field order when any field format
``V4L2_FIELD_NONE``, ``V4L2_FIELD_TOP``, ``V4L2_FIELD_BOTTOM``, or is acceptable. Drivers choose depending on hardware capabilities or
``V4L2_FIELD_INTERLACED`` formats is acceptable. Drivers choose e.g. the requested image size, and return the actual field order.
depending on hardware capabilities or e. g. the requested image Drivers must never return ``V4L2_FIELD_ANY``.
size, and return the actual field order. Drivers must never return If multiple field orders are possible the
``V4L2_FIELD_ANY``. If multiple field orders are possible the
driver must choose one of the possible field orders during driver must choose one of the possible field orders during
:ref:`VIDIOC_S_FMT <VIDIOC_G_FMT>` or :ref:`VIDIOC_S_FMT <VIDIOC_G_FMT>` or
:ref:`VIDIOC_TRY_FMT <VIDIOC_G_FMT>`. struct :ref:`VIDIOC_TRY_FMT <VIDIOC_G_FMT>`. struct
@ -88,9 +87,8 @@ enum v4l2_field
``V4L2_FIELD_ANY``. ``V4L2_FIELD_ANY``.
* - ``V4L2_FIELD_NONE`` * - ``V4L2_FIELD_NONE``
- 1 - 1
- Images are in progressive format, not interlaced. The driver may - Images are in progressive (frame-based) format, not interlaced
also indicate this order when it cannot distinguish between (field-based).
``V4L2_FIELD_TOP`` and ``V4L2_FIELD_BOTTOM``.
* - ``V4L2_FIELD_TOP`` * - ``V4L2_FIELD_TOP``
- 2 - 2
- Images consist of the top (aka odd) field only. - Images consist of the top (aka odd) field only.