From: Kamil Debski Date: Fri, 11 Mar 2011 09:16:22 +0000 (-0300) Subject: [media] v4l: Documentation for the NV12MT format X-Git-Tag: firefly_0821_release~7613^2~1709^2~124 X-Git-Url: http://demsky.eecs.uci.edu/git/?a=commitdiff_plain;h=bd08a0cd5f546916a9454ae2c35756ed77957458;p=firefly-linux-kernel-4.4.55.git [media] v4l: Documentation for the NV12MT format Added documentation for V4L2_PIX_FMT_NV12MT format. This is a YUV 4:2:0 format with macro block size of 64x32 and specific order of macro blocks in the memory. Signed-off-by: Kamil Debski Signed-off-by: Kyungmin Park Signed-off-by: Mauro Carvalho Chehab --- diff --git a/Documentation/DocBook/media-entities.tmpl b/Documentation/DocBook/media-entities.tmpl index 40158ee3d369..5d259c632cdf 100644 --- a/Documentation/DocBook/media-entities.tmpl +++ b/Documentation/DocBook/media-entities.tmpl @@ -272,6 +272,7 @@ + diff --git a/Documentation/DocBook/v4l/nv12mt.gif b/Documentation/DocBook/v4l/nv12mt.gif new file mode 100644 index 000000000000..ef2d4cf8367b Binary files /dev/null and b/Documentation/DocBook/v4l/nv12mt.gif differ diff --git a/Documentation/DocBook/v4l/nv12mt_example.gif b/Documentation/DocBook/v4l/nv12mt_example.gif new file mode 100644 index 000000000000..df81d68108ee Binary files /dev/null and b/Documentation/DocBook/v4l/nv12mt_example.gif differ diff --git a/Documentation/DocBook/v4l/pixfmt-nv12mt.xml b/Documentation/DocBook/v4l/pixfmt-nv12mt.xml new file mode 100644 index 000000000000..5cb5bec8b653 --- /dev/null +++ b/Documentation/DocBook/v4l/pixfmt-nv12mt.xml @@ -0,0 +1,74 @@ + + + V4L2_PIX_FMT_NV12MT ('TM12') + &manvol; + + + V4L2_PIX_FMT_NV12MT + + Formats with ½ horizontal and vertical +chroma resolution. This format has two planes - one for luminance and one for +chrominance. Chroma samples are interleaved. The difference to +V4L2_PIX_FMT_NV12 is the memory layout. Pixels are +grouped in macroblocks of 64x32 size. The order of macroblocks in memory is +also not standard. + + + + Description + + This is the two-plane versions of the YUV 4:2:0 format where data +is grouped into 64x32 macroblocks. The three components are separated into two +sub-images or planes. The Y plane has one byte per pixel and pixels are grouped +into 64x32 macroblocks. The CbCr plane has the same width, in bytes, as the Y +plane (and the image), but is half as tall in pixels. The chroma plane is also +grouped into 64x32 macroblocks. + Width of the buffer has to be aligned to the multiple of 128, and +height alignment is 32. Every four adjactent buffers - two horizontally and two +vertically are grouped together and are located in memory in Z or flipped Z +order. + Layout of macroblocks in memory is presented in the following +figure. +
+ <constant>V4L2_PIX_FMT_NV12MT</constant> macroblock Z shape +memory layout + + + + + +
+ The requirement that width is multiple of 128 is implemented because, +the Z shape cannot be cut in half horizontally. In case the vertical resolution +of macroblocks is odd then the last row of macroblocks is arranged in a linear +order. + In case of chroma the layout is identical. Cb and Cr samples are +interleaved. Height of the buffer is aligned to 32. + + + Memory layout of macroblocks in <constant>V4L2_PIX_FMT_NV12 +</constant> format pixel image - extreme case + +
+ Example <constant>V4L2_PIX_FMT_NV12MT</constant> memory +layout of macroblocks + + + + + +
+ Memory layout of macroblocks of V4L2_PIX_FMT_NV12MT + format in most extreme case. + + + + + + diff --git a/Documentation/DocBook/v4l/pixfmt.xml b/Documentation/DocBook/v4l/pixfmt.xml index f8436dcb7414..c6fdcbbd1b41 100644 --- a/Documentation/DocBook/v4l/pixfmt.xml +++ b/Documentation/DocBook/v4l/pixfmt.xml @@ -709,6 +709,7 @@ information. &sub-yuv411p; &sub-nv12; &sub-nv12m; + &sub-nv12mt; &sub-nv16;