From 007701e2c4de94109864c8e85e39b6d8fc474170 Mon Sep 17 00:00:00 2001 From: Muralidharan Karicheri Date: Thu, 3 Dec 2009 01:13:17 -0300 Subject: V4L/DVB (13572): v4l2-spec: Digital Video Timings API documentation This patch updates the v4l2-dvb documentation for the new video timings API added. Also updated the document based on comments from Hans Verkuil. Signed-off-by: Muralidharan Karicheri Signed-off-by: Hans Verkuil Signed-off-by: Mauro Carvalho Chehab --- Documentation/DocBook/v4l/common.xml | 35 +++++++++++++++++++++++++++++++++++ 1 file changed, 35 insertions(+) (limited to 'Documentation/DocBook/v4l/common.xml') diff --git a/Documentation/DocBook/v4l/common.xml b/Documentation/DocBook/v4l/common.xml index b1a81d246d5..c65f0ac9b6e 100644 --- a/Documentation/DocBook/v4l/common.xml +++ b/Documentation/DocBook/v4l/common.xml @@ -716,6 +716,41 @@ if (-1 == ioctl (fd, &VIDIOC-S-STD;, &std_id)) { } +
+ Digital Video (DV) Timings + + The video standards discussed so far has been dealing with Analog TV and the +corresponding video timings. Today there are many more different hardware interfaces +such as High Definition TV interfaces (HDMI), VGA, DVI connectors etc., that carry +video signals and there is a need to extend the API to select the video timings +for these interfaces. Since it is not possible to extend the &v4l2-std-id; due to +the limited bits available, a new set of IOCTLs is added to set/get video timings at +the input and output: + + DV Presets: Digital Video (DV) presets. These are IDs representing a +video timing at the input/output. Presets are pre-defined timings implemented +by the hardware according to video standards. A __u32 data type is used to represent +a preset unlike the bit mask that is used in &v4l2-std-id; allowing future extensions +to support as many different presets as needed. + + + Custom DV Timings: This will allow applications to define more detailed +custom video timings for the interface. This includes parameters such as width, height, +polarities, frontporch, backporch etc. + + + + To enumerate and query the attributes of DV presets supported by a device, +applications use the &VIDIOC-ENUM-DV-PRESETS; ioctl. To get the current DV preset, +applications use the &VIDIOC-G-DV-PRESET; ioctl and to set a preset they use the +&VIDIOC-S-DV-PRESET; ioctl. + To set custom DV timings for the device, applications use the +&VIDIOC-S-DV-TIMINGS; ioctl and to get current custom DV timings they use the +&VIDIOC-G-DV-TIMINGS; ioctl. + Applications can make use of the and + flags to decide what ioctls are available to set the +video timings for the device. +
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