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Diffstat (limited to 'Documentation/userspace-api/media/v4l/pixfmt-packed-yuv.rst')
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1 files changed, 199 insertions, 213 deletions
diff --git a/Documentation/userspace-api/media/v4l/pixfmt-packed-yuv.rst b/Documentation/userspace-api/media/v4l/pixfmt-packed-yuv.rst index 84262208dd1c..eb551b57557e 100644 --- a/Documentation/userspace-api/media/v4l/pixfmt-packed-yuv.rst +++ b/Documentation/userspace-api/media/v4l/pixfmt-packed-yuv.rst @@ -6,12 +6,32 @@ Packed YUV formats ****************** -Description -=========== +Similarly to the packed RGB formats, the packed YUV formats store the Y, Cb and +Cr components consecutively in memory. They may apply subsampling to the chroma +components and thus differ in how they interlave the three components. -Similar to the packed RGB formats these formats store the Y, Cb and Cr -component of each pixel in one 16 or 32 bit word. +.. note:: + + - In all the tables that follow, bit 7 is the most significant bit in a byte. + - 'Y', 'Cb' and 'Cr' denote bits of the luma, blue chroma (also known as + 'U') and red chroma (also known as 'V') components respectively. 'A' + denotes bits of the alpha component (if supported by the format), and 'X' + denotes padding bits. + + +4:4:4 Subsampling +================= +These formats do not subsample the chroma components and store each pixels as a +full triplet of Y, Cb and Cr values. + +The next table lists the packed YUV 4:4:4 formats with less than 8 bits per +component. They are named based on the order of the Y, Cb and Cr components as +seen in a 16-bit word, which is then stored in memory in little endian byte +order, and on the number of bits for each component. For instance the YUV565 +format stores a pixel in a 16-bit word [15:0] laid out at as [Y'\ :sub:`4-0` +Cb\ :sub:`5-0` Cr\ :sub:`4-0`], and stored in memory in two bytes, +[Cb\ :sub:`2-0` Cr\ :sub:`4-0`] followed by [Y'\ :sub:`4-0` Cb\ :sub:`5-3`]. .. raw:: latex @@ -19,11 +39,9 @@ component of each pixel in one 16 or 32 bit word. \tiny \setlength{\tabcolsep}{2pt} -.. _packed-yuv-formats: - -.. tabularcolumns:: |p{2.5cm}|p{0.69cm}|p{0.31cm}|p{0.31cm}|p{0.31cm}|p{0.31cm}|p{0.31cm}|p{0.31cm}|p{0.31cm}|p{0.31cm}|p{0.31cm}|p{0.31cm}|p{0.31cm}|p{0.31cm}|p{0.31cm}|p{0.31cm}|p{0.31cm}|p{0.31cm}|p{0.31cm}|p{0.31cm}|p{0.31cm}|p{0.31cm}|p{0.31cm}|p{0.31cm}|p{0.31cm}|p{0.31cm}|p{0.31cm}|p{0.31cm}|p{0.31cm}|p{0.31cm}|p{0.31cm}|p{0.31cm}|p{0.31cm}|p{0.31cm}| +.. tabularcolumns:: |p{2.5cm}|p{0.69cm}|p{0.31cm}|p{0.31cm}|p{0.31cm}|p{0.31cm}|p{0.31cm}|p{0.31cm}|p{0.31cm}|p{0.31cm}|p{0.31cm}|p{0.31cm}|p{0.31cm}|p{0.31cm}|p{0.31cm}|p{0.31cm}|p{0.31cm}|p{0.31cm}| -.. flat-table:: Packed YUV Image Formats +.. flat-table:: Packed YUV 4:4:4 Image Formats (less than 8bpc) :header-rows: 2 :stub-columns: 0 @@ -34,10 +52,6 @@ component of each pixel in one 16 or 32 bit word. - :cspan:`7` Byte 1 - - :cspan:`7` Byte 2 - - - :cspan:`7` Byte 3 - * - - - 7 @@ -58,24 +72,6 @@ component of each pixel in one 16 or 32 bit word. - 1 - 0 - - 7 - - 6 - - 5 - - 4 - - 3 - - 2 - - 1 - - 0 - - - 7 - - 6 - - 5 - - 4 - - 3 - - 2 - - 1 - - 0 - * .. _V4L2-PIX-FMT-YUV444: - ``V4L2_PIX_FMT_YUV444`` @@ -99,8 +95,6 @@ component of each pixel in one 16 or 32 bit word. - Y'\ :sub:`1` - Y'\ :sub:`0` - - :cspan:`15` - * .. _V4L2-PIX-FMT-YUV555: - ``V4L2_PIX_FMT_YUV555`` @@ -124,7 +118,6 @@ component of each pixel in one 16 or 32 bit word. - Cb\ :sub:`4` - Cb\ :sub:`3` - - :cspan:`15` * .. _V4L2-PIX-FMT-YUV565: - ``V4L2_PIX_FMT_YUV565`` @@ -148,226 +141,219 @@ component of each pixel in one 16 or 32 bit word. - Cb\ :sub:`4` - Cb\ :sub:`3` - - :cspan:`15` +.. raw:: latex - * .. _V4L2-PIX-FMT-YUV32: + \endgroup - - ``V4L2_PIX_FMT_YUV32`` - - 'YUV4' +.. note:: - - a\ :sub:`7` - - a\ :sub:`6` - - a\ :sub:`5` - - a\ :sub:`4` - - a\ :sub:`3` - - a\ :sub:`2` - - a\ :sub:`1` - - a\ :sub:`0` + For the YUV444 and YUV555 formats, the value of alpha bits is undefined + when reading from the driver, ignored when writing to the driver, except + when alpha blending has been negotiated for a :ref:`Video Overlay + <overlay>` or :ref:`Video Output Overlay <osd>`. - - Y'\ :sub:`7` - - Y'\ :sub:`6` - - Y'\ :sub:`5` - - Y'\ :sub:`4` - - Y'\ :sub:`3` - - Y'\ :sub:`2` - - Y'\ :sub:`1` - - Y'\ :sub:`0` - - Cb\ :sub:`7` - - Cb\ :sub:`6` - - Cb\ :sub:`5` - - Cb\ :sub:`4` - - Cb\ :sub:`3` - - Cb\ :sub:`2` - - Cb\ :sub:`1` - - Cb\ :sub:`0` +The next table lists the packed YUV 4:4:4 formats with 8 bits per component. +They are named based on the order of the Y, Cb and Cr components as stored in +memory, and on the total number of bits per pixel. For instance, the VUYX32 +format stores a pixel with Cr\ :sub:`7-0` in the first byte, Cb\ :sub:`7-0` in +the second byte and Y'\ :sub:`7-0` in the third byte. - - Cr\ :sub:`7` - - Cr\ :sub:`6` - - Cr\ :sub:`5` - - Cr\ :sub:`4` - - Cr\ :sub:`3` - - Cr\ :sub:`2` - - Cr\ :sub:`1` - - Cr\ :sub:`0` +.. flat-table:: Packed YUV Image Formats (8bpc) + :header-rows: 1 + :stub-columns: 0 - * .. _V4L2-PIX-FMT-AYUV32: + * - Identifier + - Code + - Byte 0 + - Byte 1 + - Byte 2 + - Byte 3 - - ``V4L2_PIX_FMT_AYUV32`` - - 'AYUV' + * .. _V4L2-PIX-FMT-YUV32: - - a\ :sub:`7` - - a\ :sub:`6` - - a\ :sub:`5` - - a\ :sub:`4` - - a\ :sub:`3` - - a\ :sub:`2` - - a\ :sub:`1` - - a\ :sub:`0` + - ``V4L2_PIX_FMT_YUV32`` + - 'YUV4' - - Y'\ :sub:`7` - - Y'\ :sub:`6` - - Y'\ :sub:`5` - - Y'\ :sub:`4` - - Y'\ :sub:`3` - - Y'\ :sub:`2` - - Y'\ :sub:`1` - - Y'\ :sub:`0` + - A\ :sub:`7-0` + - Y'\ :sub:`7-0` + - Cb\ :sub:`7-0` + - Cr\ :sub:`7-0` - - Cb\ :sub:`7` - - Cb\ :sub:`6` - - Cb\ :sub:`5` - - Cb\ :sub:`4` - - Cb\ :sub:`3` - - Cb\ :sub:`2` - - Cb\ :sub:`1` - - Cb\ :sub:`0` + * .. _V4L2-PIX-FMT-AYUV32: - - Cr\ :sub:`7` - - Cr\ :sub:`6` - - Cr\ :sub:`5` - - Cr\ :sub:`4` - - Cr\ :sub:`3` - - Cr\ :sub:`2` - - Cr\ :sub:`1` - - Cr\ :sub:`0` + - ``V4L2_PIX_FMT_AYUV32`` + - 'AYUV' + + - A\ :sub:`7-0` + - Y'\ :sub:`7-0` + - Cb\ :sub:`7-0` + - Cr\ :sub:`7-0` * .. _V4L2-PIX-FMT-XYUV32: - ``V4L2_PIX_FMT_XYUV32`` - 'XYUV' - - - - - - - - - - - - - - - - - - - Y'\ :sub:`7` - - Y'\ :sub:`6` - - Y'\ :sub:`5` - - Y'\ :sub:`4` - - Y'\ :sub:`3` - - Y'\ :sub:`2` - - Y'\ :sub:`1` - - Y'\ :sub:`0` - - - Cb\ :sub:`7` - - Cb\ :sub:`6` - - Cb\ :sub:`5` - - Cb\ :sub:`4` - - Cb\ :sub:`3` - - Cb\ :sub:`2` - - Cb\ :sub:`1` - - Cb\ :sub:`0` - - - Cr\ :sub:`7` - - Cr\ :sub:`6` - - Cr\ :sub:`5` - - Cr\ :sub:`4` - - Cr\ :sub:`3` - - Cr\ :sub:`2` - - Cr\ :sub:`1` - - Cr\ :sub:`0` + - X\ :sub:`7-0` + - Y'\ :sub:`7-0` + - Cb\ :sub:`7-0` + - Cr\ :sub:`7-0` * .. _V4L2-PIX-FMT-VUYA32: - ``V4L2_PIX_FMT_VUYA32`` - 'VUYA' - - Cr\ :sub:`7` - - Cr\ :sub:`6` - - Cr\ :sub:`5` - - Cr\ :sub:`4` - - Cr\ :sub:`3` - - Cr\ :sub:`2` - - Cr\ :sub:`1` - - Cr\ :sub:`0` - - - Cb\ :sub:`7` - - Cb\ :sub:`6` - - Cb\ :sub:`5` - - Cb\ :sub:`4` - - Cb\ :sub:`3` - - Cb\ :sub:`2` - - Cb\ :sub:`1` - - Cb\ :sub:`0` - - - Y'\ :sub:`7` - - Y'\ :sub:`6` - - Y'\ :sub:`5` - - Y'\ :sub:`4` - - Y'\ :sub:`3` - - Y'\ :sub:`2` - - Y'\ :sub:`1` - - Y'\ :sub:`0` - - - a\ :sub:`7` - - a\ :sub:`6` - - a\ :sub:`5` - - a\ :sub:`4` - - a\ :sub:`3` - - a\ :sub:`2` - - a\ :sub:`1` - - a\ :sub:`0` + - Cr\ :sub:`7-0` + - Cb\ :sub:`7-0` + - Y'\ :sub:`7-0` + - A\ :sub:`7-0` * .. _V4L2-PIX-FMT-VUYX32: - ``V4L2_PIX_FMT_VUYX32`` - 'VUYX' - - Cr\ :sub:`7` - - Cr\ :sub:`6` - - Cr\ :sub:`5` - - Cr\ :sub:`4` - - Cr\ :sub:`3` - - Cr\ :sub:`2` - - Cr\ :sub:`1` - - Cr\ :sub:`0` + - Cr\ :sub:`7-0` + - Cb\ :sub:`7-0` + - Y'\ :sub:`7-0` + - X\ :sub:`7-0` - - Cb\ :sub:`7` - - Cb\ :sub:`6` - - Cb\ :sub:`5` - - Cb\ :sub:`4` - - Cb\ :sub:`3` - - Cb\ :sub:`2` - - Cb\ :sub:`1` - - Cb\ :sub:`0` +.. note:: - - Y'\ :sub:`7` - - Y'\ :sub:`6` - - Y'\ :sub:`5` - - Y'\ :sub:`4` + - The alpha component is expected to contain a meaningful value that can be + used by drivers and applications. + - The padding bits contain undefined values that must be ignored by all + applications and drivers. + + +4:2:2 Subsampling +================= + +These formats, commonly referred to as YUYV or YUY2, subsample the chroma +components horizontally by 2, storing 2 pixels in 4 bytes. + +.. flat-table:: Packed YUV 4:2:2 Formats + :header-rows: 1 + :stub-columns: 0 + + * - Identifier + - Code + - Byte 0 + - Byte 1 + - Byte 2 + - Byte 3 + - Byte 4 + - Byte 5 + - Byte 6 + - Byte 7 + * .. _V4L2-PIX-FMT-UYVY: + + - ``V4L2_PIX_FMT_UYVY`` + - 'UYVY' + + - Cb\ :sub:`0` + - Y'\ :sub:`0` + - Cr\ :sub:`0` + - Y'\ :sub:`1` + - Cb\ :sub:`2` + - Y'\ :sub:`2` + - Cr\ :sub:`2` - Y'\ :sub:`3` + * .. _V4L2-PIX-FMT-VYUY: + + - ``V4L2_PIX_FMT_VYUY`` + - 'VYUY' + + - Cr\ :sub:`0` + - Y'\ :sub:`0` + - Cb\ :sub:`0` + - Y'\ :sub:`1` + - Cr\ :sub:`2` - Y'\ :sub:`2` + - Cb\ :sub:`2` + - Y'\ :sub:`3` + * .. _V4L2-PIX-FMT-YUYV: + + - ``V4L2_PIX_FMT_YUYV`` + - 'YUYV' + + - Y'\ :sub:`0` + - Cb\ :sub:`0` - Y'\ :sub:`1` + - Cr\ :sub:`0` + - Y'\ :sub:`2` + - Cb\ :sub:`2` + - Y'\ :sub:`3` + - Cr\ :sub:`2` + * .. _V4L2-PIX-FMT-YVYU: + + - ``V4L2_PIX_FMT_YVYU`` + - 'YVYU' + - Y'\ :sub:`0` + - Cr\ :sub:`0` + - Y'\ :sub:`1` + - Cb\ :sub:`0` + - Y'\ :sub:`2` + - Cr\ :sub:`2` + - Y'\ :sub:`3` + - Cb\ :sub:`2` - - - - - - - - - - - - - - - - +**Color Sample Location:** +Chroma samples are :ref:`interstitially sited<yuv-chroma-centered>` +horizontally. -.. raw:: latex - \endgroup +4:1:1 Subsampling +================= + +This format subsamples the chroma components horizontally by 4, storing 8 +pixels in 12 bytes. + +.. flat-table:: Packed YUV 4:1:1 Formats + :header-rows: 1 + :stub-columns: 0 + + * - Identifier + - Code + - Byte 0 + - Byte 1 + - Byte 2 + - Byte 3 + - Byte 4 + - Byte 5 + - Byte 6 + - Byte 7 + - Byte 8 + - Byte 9 + - Byte 10 + - Byte 11 + * .. _V4L2-PIX-FMT-Y41P: + + - ``V4L2_PIX_FMT_Y41P`` + - 'Y41P' + + - Cb\ :sub:`0` + - Y'\ :sub:`0` + - Cr\ :sub:`0` + - Y'\ :sub:`1` + - Cb\ :sub:`4` + - Y'\ :sub:`2` + - Cr\ :sub:`4` + - Y'\ :sub:`3` + - Y'\ :sub:`4` + - Y'\ :sub:`5` + - Y'\ :sub:`6` + - Y'\ :sub:`7` .. note:: - #) Bit 7 is the most significant bit; + Do not confuse ``V4L2_PIX_FMT_Y41P`` with + :ref:`V4L2_PIX_FMT_YUV411P <V4L2-PIX-FMT-YUV411P>`. Y41P is derived from + "YUV 4:1:1 *packed*", while YUV411P stands for "YUV 4:1:1 *planar*". - #) The value of a = alpha bits is undefined when reading from the driver, - ignored when writing to the driver, except when alpha blending has - been negotiated for a :ref:`Video Overlay <overlay>` or - :ref:`Video Output Overlay <osd>` for the formats Y444, YUV555 and - YUV4. However, for formats AYUV32 and VUYA32, the alpha component is - expected to contain a meaningful value that can be used by drivers - and applications. And, the formats XYUV32 and VUYX32 contain undefined - alpha values that must be ignored by all applications and drivers. +**Color Sample Location:** +Chroma samples are :ref:`interstitially sited<yuv-chroma-centered>` +horizontally. |