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Diffstat (limited to 'Documentation/DocBook/media/v4l/pixfmt-yuv420m.xml')
| -rw-r--r-- | Documentation/DocBook/media/v4l/pixfmt-yuv420m.xml | 26 |
1 files changed, 17 insertions, 9 deletions
diff --git a/Documentation/DocBook/media/v4l/pixfmt-yuv420m.xml b/Documentation/DocBook/media/v4l/pixfmt-yuv420m.xml index e781cc617..7d13fe966 100644 --- a/Documentation/DocBook/media/v4l/pixfmt-yuv420m.xml +++ b/Documentation/DocBook/media/v4l/pixfmt-yuv420m.xml @@ -1,35 +1,43 @@ - <refentry id="V4L2-PIX-FMT-YUV420M"> + <refentry> <refmeta> - <refentrytitle>V4L2_PIX_FMT_YUV420M ('YM12')</refentrytitle> + <refentrytitle>V4L2_PIX_FMT_YUV420M ('YM12'), V4L2_PIX_FMT_YVU420M ('YM21')</refentrytitle> &manvol; </refmeta> <refnamediv> - <refname> <constant>V4L2_PIX_FMT_YUV420M</constant></refname> - <refpurpose>Variation of <constant>V4L2_PIX_FMT_YUV420</constant> - with planes non contiguous in memory. </refpurpose> + <refname id="V4L2-PIX-FMT-YUV420M"><constant>V4L2_PIX_FMT_YUV420M</constant></refname> + <refname id="V4L2-PIX-FMT-YVU420M"><constant>V4L2_PIX_FMT_YVU420M</constant></refname> + <refpurpose>Variation of <constant>V4L2_PIX_FMT_YUV420</constant> and + <constant>V4L2_PIX_FMT_YVU420</constant> with planes non contiguous + in memory.</refpurpose> </refnamediv> <refsect1> <title>Description</title> <para>This is a multi-planar format, as opposed to a packed format. -The three components are separated into three sub- images or planes. +The three components are separated into three sub-images or planes.</para> -The Y plane is first. The Y plane has one byte per pixel. The Cb data + <para>The Y plane is first. The Y plane has one byte per pixel. +For <constant>V4L2_PIX_FMT_YUV420M</constant> the Cb data constitutes the second plane which is half the width and half the height of the Y plane (and of the image). Each Cb belongs to four pixels, a two-by-two square of the image. For example, Cb<subscript>0</subscript> belongs to Y'<subscript>00</subscript>, Y'<subscript>01</subscript>, Y'<subscript>10</subscript>, and Y'<subscript>11</subscript>. The Cr data, just like the Cb plane, is -in the third plane. </para> +in the third plane.</para> + + <para><constant>V4L2_PIX_FMT_YVU420M</constant> is the same except +the Cr data is stored in the second plane and the Cb data in the third plane. +</para> <para>If the Y plane has pad bytes after each row, then the Cb and Cr planes have half as many pad bytes after their rows. In other words, two Cx rows (including padding) is exactly as long as one Y row (including padding).</para> - <para><constant>V4L2_PIX_FMT_YUV420M</constant> is intended to be + <para><constant>V4L2_PIX_FMT_YUV420M</constant> and +<constant>V4L2_PIX_FMT_YVU420M</constant> are intended to be used only in drivers and applications that support the multi-planar API, described in <xref linkend="planar-apis"/>. </para> |