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authorLinus Torvalds <torvalds@linux-foundation.org>2019-07-09 09:47:22 -0700
committerLinus Torvalds <torvalds@linux-foundation.org>2019-07-09 09:47:22 -0700
commited63b9c873601ca113da5c7b1745e3946493e9f3 (patch)
tree94e96db2b79a8d123c0645dd64b3830bc4d20bfe /Documentation/media/uapi/v4l/field-order.rst
parentMerge tag 'please-pull-for_5.3' of git://git.kernel.org/pub/scm/linux/kernel/git/ras/ras (diff)
parentmedia: allegro: use new v4l2_m2m_ioctl_try_encoder_cmd funcs (diff)
downloadlinux-dev-ed63b9c873601ca113da5c7b1745e3946493e9f3.tar.xz
linux-dev-ed63b9c873601ca113da5c7b1745e3946493e9f3.zip
Merge tag 'media/v5.3-1' of git://git.kernel.org/pub/scm/linux/kernel/git/mchehab/linux-media
Pull media updates from Mauro Carvalho Chehab: - new Atmel microship ISC driver - coda has gained support for mpeg2 and mpeg4 - cxusb gained support for analog TV - rockchip staging driver was split into two separate staging drivers - added a new staging driver for Allegro DVT video IP core - added a new staging driver for Amlogic Meson video decoder - lots of improvements and cleanups * tag 'media/v5.3-1' of git://git.kernel.org/pub/scm/linux/kernel/git/mchehab/linux-media: (398 commits) media: allegro: use new v4l2_m2m_ioctl_try_encoder_cmd funcs media: doc-rst: Fix typos media: radio-raremono: change devm_k*alloc to k*alloc media: stv0297: fix frequency range limit media: rc: Prefer KEY_NUMERIC_* for number buttons on remotes media: dvb_frontend: split dvb_frontend_handle_ioctl function media: mceusb: disable "nonsensical irdata" messages media: rc: remove redundant dev_err message media: cec-notifier: add new notifier functions media: cec: add struct cec_connector_info support media: cec-notifier: rename variables, check kstrdup and n->conn_name media: MAINTAINERS: Add maintainers for Media Controller media: staging: media: tegra-vde: Defer dmabuf's unmapping media: staging: media: tegra-vde: Add IOMMU support media: hdpvr: fix locking and a missing msleep media: v4l2: Test type instead of cfg->type in v4l2_ctrl_new_custom() media: atmel: atmel-isc: fix i386 build error media: v4l2-ctrl: Move compound control initialization media: hantro: Use vb2_get_buffer media: pci: cx88: Change the type of 'missed' to u64 ...
Diffstat (limited to 'Documentation/media/uapi/v4l/field-order.rst')
-rw-r--r--Documentation/media/uapi/v4l/field-order.rst17
1 files changed, 11 insertions, 6 deletions
diff --git a/Documentation/media/uapi/v4l/field-order.rst b/Documentation/media/uapi/v4l/field-order.rst
index d640e922a974..c422bebe4314 100644
--- a/Documentation/media/uapi/v4l/field-order.rst
+++ b/Documentation/media/uapi/v4l/field-order.rst
@@ -51,6 +51,11 @@ determined by the video standard. Hence the distinction between temporal
and spatial order of fields. The diagrams below should make this
clearer.
+In V4L it is assumed that all video cameras transmit fields on the media
+bus in the same order they were captured, so if the top field was
+captured first (is the older field), the top field is also transmitted
+first on the bus.
+
All video capture and output devices must report the current field
order. Some drivers may permit the selection of a different order, to
this end applications initialize the ``field`` field of struct
@@ -101,10 +106,10 @@ enum v4l2_field
* - ``V4L2_FIELD_INTERLACED``
- 4
- Images contain both fields, interleaved line by line. The temporal
- order of the fields (whether the top or bottom field is first
- transmitted) depends on the current video standard. M/NTSC
- transmits the bottom field first, all other standards the top
- field first.
+ order of the fields (whether the top or bottom field is older)
+ depends on the current video standard. In M/NTSC the bottom
+ field is the older field. In all other standards the top field
+ is the older field.
* - ``V4L2_FIELD_SEQ_TB``
- 5
- Images contain both fields, the top field lines are stored first
@@ -135,11 +140,11 @@ enum v4l2_field
* - ``V4L2_FIELD_INTERLACED_TB``
- 8
- Images contain both fields, interleaved line by line, top field
- first. The top field is transmitted first.
+ first. The top field is the older field.
* - ``V4L2_FIELD_INTERLACED_BT``
- 9
- Images contain both fields, interleaved line by line, top field
- first. The bottom field is transmitted first.
+ first. The bottom field is the older field.