diff options
Diffstat (limited to 'Documentation/DocBook/media')
| -rw-r--r-- | Documentation/DocBook/media/v4l/pixfmt.xml | 113 | ||||
| -rw-r--r-- | Documentation/DocBook/media/v4l/subdev-formats.xml | 12 |
2 files changed, 101 insertions, 24 deletions
diff --git a/Documentation/DocBook/media/v4l/pixfmt.xml b/Documentation/DocBook/media/v4l/pixfmt.xml index 6c3d65346076..e7d88482a522 100644 --- a/Documentation/DocBook/media/v4l/pixfmt.xml +++ b/Documentation/DocBook/media/v4l/pixfmt.xml @@ -157,6 +157,14 @@ see <xref linkend="colorspaces" />.</entry> capture streams and by the application for output streams, see <xref linkend="colorspaces" />.</entry> </row> + <row> + <entry>&v4l2-xfer-func;</entry> + <entry><structfield>xfer_func</structfield></entry> + <entry>This information supplements the +<structfield>colorspace</structfield> and must be set by the driver for +capture streams and by the application for output streams, +see <xref linkend="colorspaces" />.</entry> + </row> </tbody> </tgroup> </table> @@ -264,9 +272,17 @@ see <xref linkend="colorspaces" />.</entry> capture streams and by the application for output streams, see <xref linkend="colorspaces" />.</entry> </row> + <row> + <entry>&v4l2-xfer-func;</entry> + <entry><structfield>xfer_func</structfield></entry> + <entry>This information supplements the +<structfield>colorspace</structfield> and must be set by the driver for +capture streams and by the application for output streams, +see <xref linkend="colorspaces" />.</entry> + </row> <row> <entry>__u8</entry> - <entry><structfield>reserved[8]</structfield></entry> + <entry><structfield>reserved[7]</structfield></entry> <entry>Reserved for future extensions. Should be zeroed by the application.</entry> </row> @@ -476,15 +492,16 @@ is also very useful.</para> <section> <title>Defining Colorspaces in V4L2</title> - <para>In V4L2 colorspaces are defined by three values. The first is the colorspace -identifier (&v4l2-colorspace;) which defines the chromaticities, the transfer + <para>In V4L2 colorspaces are defined by four values. The first is the colorspace +identifier (&v4l2-colorspace;) which defines the chromaticities, the default transfer function, the default Y'CbCr encoding and the default quantization method. The second -is the Y'CbCr encoding identifier (&v4l2-ycbcr-encoding;) to specify non-standard -Y'CbCr encodings and the third is the quantization identifier (&v4l2-quantization;) -to specify non-standard quantization methods. Most of the time only the colorspace -field of &v4l2-pix-format; or &v4l2-pix-format-mplane; needs to be filled in. Note -that the default R'G'B' quantization is full range for all colorspaces except for -BT.2020 which uses limited range R'G'B' quantization.</para> +is the transfer function identifier (&v4l2-xfer-func;) to specify non-standard +transfer functions. The third is the Y'CbCr encoding identifier (&v4l2-ycbcr-encoding;) +to specify non-standard Y'CbCr encodings and the fourth is the quantization identifier +(&v4l2-quantization;) to specify non-standard quantization methods. Most of the time +only the colorspace field of &v4l2-pix-format; or &v4l2-pix-format-mplane; needs to +be filled in. Note that the default R'G'B' quantization is full range for all +colorspaces except for BT.2020 which uses limited range R'G'B' quantization.</para> <table pgwide="1" frame="none" id="v4l2-colorspace"> <title>V4L2 Colorspaces</title> @@ -549,6 +566,45 @@ BT.2020 which uses limited range R'G'B' quantization.</para> </tgroup> </table> + <table pgwide="1" frame="none" id="v4l2-xfer-func"> + <title>V4L2 Transfer Function</title> + <tgroup cols="2" align="left"> + &cs-def; + <thead> + <row> + <entry>Identifier</entry> + <entry>Details</entry> + </row> + </thead> + <tbody valign="top"> + <row> + <entry><constant>V4L2_XFER_FUNC_DEFAULT</constant></entry> + <entry>Use the default transfer function as defined by the colorspace.</entry> + </row> + <row> + <entry><constant>V4L2_XFER_FUNC_709</constant></entry> + <entry>Use the Rec. 709 transfer function.</entry> + </row> + <row> + <entry><constant>V4L2_XFER_FUNC_SRGB</constant></entry> + <entry>Use the sRGB transfer function.</entry> + </row> + <row> + <entry><constant>V4L2_XFER_FUNC_ADOBERGB</constant></entry> + <entry>Use the AdobeRGB transfer function.</entry> + </row> + <row> + <entry><constant>V4L2_XFER_FUNC_SMPTE240M</constant></entry> + <entry>Use the SMPTE 240M transfer function.</entry> + </row> + <row> + <entry><constant>V4L2_XFER_FUNC_NONE</constant></entry> + <entry>Do not use a transfer function (i.e. use linear RGB values).</entry> + </row> + </tbody> + </tgroup> + </table> + <table pgwide="1" frame="none" id="v4l2-ycbcr-encoding"> <title>V4L2 Y'CbCr Encodings</title> <tgroup cols="2" align="left"> @@ -636,7 +692,8 @@ is mapped to [16…235]. Cb and Cr are mapped from [-0.5…0.5] to [16 <section id="col-smpte-170m"> <title>Colorspace SMPTE 170M (<constant>V4L2_COLORSPACE_SMPTE170M</constant>)</title> <para>The <xref linkend="smpte170m" /> standard defines the colorspace used by NTSC and PAL and by SDTV -in general. The default Y'CbCr encoding is <constant>V4L2_YCBCR_ENC_601</constant>. +in general. The default transfer function is <constant>V4L2_XFER_FUNC_709</constant>. +The default Y'CbCr encoding is <constant>V4L2_YCBCR_ENC_601</constant>. The default Y'CbCr quantization is limited range. The chromaticities of the primary colors and the white reference are:</para> <table frame="none"> @@ -718,7 +775,8 @@ rarely seen.</para> <section id="col-rec709"> <title>Colorspace Rec. 709 (<constant>V4L2_COLORSPACE_REC709</constant>)</title> - <para>The <xref linkend="itu709" /> standard defines the colorspace used by HDTV in general. The default + <para>The <xref linkend="itu709" /> standard defines the colorspace used by HDTV in general. +The default transfer function is <constant>V4L2_XFER_FUNC_709</constant>. The default Y'CbCr encoding is <constant>V4L2_YCBCR_ENC_709</constant>. The default Y'CbCr quantization is limited range. The chromaticities of the primary colors and the white reference are:</para> <table frame="none"> @@ -829,9 +887,11 @@ The xvYCC encodings always use full range quantization.</para> <section id="col-srgb"> <title>Colorspace sRGB (<constant>V4L2_COLORSPACE_SRGB</constant>)</title> - <para>The <xref linkend="srgb" /> standard defines the colorspace used by most webcams and computer graphics. The -default Y'CbCr encoding is <constant>V4L2_YCBCR_ENC_SYCC</constant>. The default Y'CbCr quantization -is full range. The chromaticities of the primary colors and the white reference are:</para> + <para>The <xref linkend="srgb" /> standard defines the colorspace used by most webcams +and computer graphics. The default transfer function is <constant>V4L2_XFER_FUNC_SRGB</constant>. +The default Y'CbCr encoding is <constant>V4L2_YCBCR_ENC_SYCC</constant>. The default Y'CbCr +quantization is full range. The chromaticities of the primary colors and the white +reference are:</para> <table frame="none"> <title>sRGB Chromaticities</title> <tgroup cols="3" align="left"> @@ -908,6 +968,7 @@ values before quantization, but this encoding does not do that.</para> <title>Colorspace Adobe RGB (<constant>V4L2_COLORSPACE_ADOBERGB</constant>)</title> <para>The <xref linkend="adobergb" /> standard defines the colorspace used by computer graphics that use the AdobeRGB colorspace. This is also known as the <xref linkend="oprgb" /> standard. +The default transfer function is <constant>V4L2_XFER_FUNC_ADOBERGB</constant>. The default Y'CbCr encoding is <constant>V4L2_YCBCR_ENC_601</constant>. The default Y'CbCr quantization is limited range. The chromaticities of the primary colors and the white reference are:</para> @@ -979,7 +1040,8 @@ SMPTE 170M/BT.601. The Y'CbCr quantization is limited range.</para> <section id="col-bt2020"> <title>Colorspace BT.2020 (<constant>V4L2_COLORSPACE_BT2020</constant>)</title> <para>The <xref linkend="itu2020" /> standard defines the colorspace used by Ultra-high definition -television (UHDTV). The default Y'CbCr encoding is <constant>V4L2_YCBCR_ENC_BT2020</constant>. +television (UHDTV). The default transfer function is <constant>V4L2_XFER_FUNC_709</constant>. +The default Y'CbCr encoding is <constant>V4L2_YCBCR_ENC_BT2020</constant>. The default R'G'B' quantization is limited range (!), and so is the default Y'CbCr quantization. The chromaticities of the primary colors and the white reference are:</para> <table frame="none"> @@ -1094,8 +1156,10 @@ clamped to the range [-0.5…0.5]. The Yc'CbcCrc quantization is limited ra <section id="col-smpte-240m"> <title>Colorspace SMPTE 240M (<constant>V4L2_COLORSPACE_SMPTE240M</constant>)</title> - <para>The <xref linkend="smpte240m" /> standard was an interim standard used during the early days of HDTV (1988-1998). -It has been superseded by Rec. 709. The default Y'CbCr encoding is <constant>V4L2_YCBCR_ENC_SMPTE240M</constant>. + <para>The <xref linkend="smpte240m" /> standard was an interim standard used during +the early days of HDTV (1988-1998). It has been superseded by Rec. 709. +The default transfer function is <constant>V4L2_XFER_FUNC_SMPTE240M</constant>. +The default Y'CbCr encoding is <constant>V4L2_YCBCR_ENC_SMPTE240M</constant>. The default Y'CbCr quantization is limited range. The chromaticities of the primary colors and the white reference are:</para> <table frame="none"> @@ -1168,8 +1232,10 @@ clamped to the range [-0.5…0.5]. The Y'CbCr quantization is limited range <section id="col-sysm"> <title>Colorspace NTSC 1953 (<constant>V4L2_COLORSPACE_470_SYSTEM_M</constant>)</title> <para>This standard defines the colorspace used by NTSC in 1953. In practice this -colorspace is obsolete and SMPTE 170M should be used instead. The default Y'CbCr encoding -is <constant>V4L2_YCBCR_ENC_601</constant>. The default Y'CbCr quantization is limited range. +colorspace is obsolete and SMPTE 170M should be used instead. +The default transfer function is <constant>V4L2_XFER_FUNC_709</constant>. +The default Y'CbCr encoding is <constant>V4L2_YCBCR_ENC_601</constant>. +The default Y'CbCr quantization is limited range. The chromaticities of the primary colors and the white reference are:</para> <table frame="none"> <title>NTSC 1953 Chromaticities</title> @@ -1246,8 +1312,10 @@ This transform is identical to one defined in SMPTE 170M/BT.601.</para> <section id="col-sysbg"> <title>Colorspace EBU Tech. 3213 (<constant>V4L2_COLORSPACE_470_SYSTEM_BG</constant>)</title> <para>The <xref linkend="tech3213" /> standard defines the colorspace used by PAL/SECAM in 1975. In practice this -colorspace is obsolete and SMPTE 170M should be used instead. The default Y'CbCr encoding -is <constant>V4L2_YCBCR_ENC_601</constant>. The default Y'CbCr quantization is limited range. +colorspace is obsolete and SMPTE 170M should be used instead. +The default transfer function is <constant>V4L2_XFER_FUNC_709</constant>. +The default Y'CbCr encoding is <constant>V4L2_YCBCR_ENC_601</constant>. +The default Y'CbCr quantization is limited range. The chromaticities of the primary colors and the white reference are:</para> <table frame="none"> <title>EBU Tech. 3213 Chromaticities</title> @@ -1320,7 +1388,8 @@ This transform is identical to one defined in SMPTE 170M/BT.601.</para> <section id="col-jpeg"> <title>Colorspace JPEG (<constant>V4L2_COLORSPACE_JPEG</constant>)</title> <para>This colorspace defines the colorspace used by most (Motion-)JPEG formats. The chromaticities -of the primary colors and the white reference are identical to sRGB. The Y'CbCr encoding is +of the primary colors and the white reference are identical to sRGB. The transfer +function use is <constant>V4L2_XFER_FUNC_SRGB</constant>. The Y'CbCr encoding is <constant>V4L2_YCBCR_ENC_601</constant> with full range quantization where Y' is scaled to [0…255] and Cb/Cr are scaled to [-128…128] and then clipped to [-128…127].</para> diff --git a/Documentation/DocBook/media/v4l/subdev-formats.xml b/Documentation/DocBook/media/v4l/subdev-formats.xml index 2588ad781242..4e73345e3eab 100644 --- a/Documentation/DocBook/media/v4l/subdev-formats.xml +++ b/Documentation/DocBook/media/v4l/subdev-formats.xml @@ -50,8 +50,16 @@ capture streams and by the application for output streams, see <xref linkend="colorspaces" />.</entry> </row> <row> - <entry>__u32</entry> - <entry><structfield>reserved</structfield>[6]</entry> + <entry>&v4l2-xfer-func;</entry> + <entry><structfield>xfer_func</structfield></entry> + <entry>This information supplements the +<structfield>colorspace</structfield> and must be set by the driver for +capture streams and by the application for output streams, +see <xref linkend="colorspaces" />.</entry> + </row> + <row> + <entry>__u16</entry> + <entry><structfield>reserved</structfield>[11]</entry> <entry>Reserved for future extensions. Applications and drivers must set the array to zero.</entry> </row> |