From 37089368c1b1bea3c71217163e6d5d3b01ef1f19 Mon Sep 17 00:00:00 2001 From: Hans Verkuil Date: Sat, 27 Mar 2010 14:10:37 -0300 Subject: [PATCH] V4L/DVB: v4l spec: document what odd and even fields are Document that odd == top and even == bottom. I can never remember this, so it is probably worth documenting. Signed-off-by: Hans Verkuil Signed-off-by: Mauro Carvalho Chehab --- Documentation/DocBook/v4l/io.xml | 8 ++++---- 1 file changed, 4 insertions(+), 4 deletions(-) diff --git a/Documentation/DocBook/v4l/io.xml b/Documentation/DocBook/v4l/io.xml index e870330cbf7..bb685ed6fe7 100644 --- a/Documentation/DocBook/v4l/io.xml +++ b/Documentation/DocBook/v4l/io.xml @@ -918,8 +918,8 @@ order. When the driver provides or accepts images field by field rather than interleaved, it is also important applications understand -how the fields combine to frames. We distinguish between top and -bottom fields, the spatial order: The first line +how the fields combine to frames. We distinguish between top (aka odd) and +bottom (aka even) fields, the spatial order: The first line of the top field is the first line of an interlaced frame, the first line of the bottom field is the second line of that frame. @@ -972,12 +972,12 @@ between V4L2_FIELD_TOP and V4L2_FIELD_TOP 2 - Images consist of the top field only. + Images consist of the top (aka odd) field only. V4L2_FIELD_BOTTOM 3 - Images consist of the bottom field only. + Images consist of the bottom (aka even) field only. Applications may wish to prevent a device from capturing interlaced images because they will have "comb" or "feathering" artefacts around moving objects.