[libcamera-devel,v7,3/7] libcamera: Convert between ColorSpace class and V4L2 formats
diff mbox series

Message ID 20211126104045.4756-4-david.plowman@raspberrypi.com
State Superseded
Headers show
Series
  • Colour spaces
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Commit Message

David Plowman Nov. 26, 2021, 10:40 a.m. UTC 
Add functions to the V4L2Device class to convert to and from
libcamera ColorSpace.

These methods are added to the base V4L2Device class so that they can
be shared both by the video device class and subdevices.

With the ColorSpace class, the color space and related other fields
are stored together, corresponding to a number of fields in the
various different V4L2 format structures. Template methods are
therefore a convenient implementation, and we must explicitly
instantiate the templates that will be needed.

Note that unset color spaces are converted to requests for the
device's "default" color space.

Signed-off-by: David Plowman <david.plowman@raspberrypi.com>
---
 include/libcamera/internal/v4l2_device.h |   7 +
 src/libcamera/v4l2_device.cpp            | 192 +++++++++++++++++++++++
 2 files changed, 199 insertions(+)

Comments

Jacopo Mondi Nov. 30, 2021, 9:11 p.m. UTC | #1 
Hi David

On Fri, Nov 26, 2021 at 10:40:41AM +0000, David Plowman wrote:
> Add functions to the V4L2Device class to convert to and from
> libcamera ColorSpace.
>
> These methods are added to the base V4L2Device class so that they can
> be shared both by the video device class and subdevices.
>
> With the ColorSpace class, the color space and related other fields
> are stored together, corresponding to a number of fields in the
> various different V4L2 format structures. Template methods are
> therefore a convenient implementation, and we must explicitly
> instantiate the templates that will be needed.
>
> Note that unset color spaces are converted to requests for the
> device's "default" color space.
>
> Signed-off-by: David Plowman <david.plowman@raspberrypi.com>
> ---
>  include/libcamera/internal/v4l2_device.h |   7 +
>  src/libcamera/v4l2_device.cpp            | 192 +++++++++++++++++++++++
>  2 files changed, 199 insertions(+)
>
> diff --git a/include/libcamera/internal/v4l2_device.h b/include/libcamera/internal/v4l2_device.h
> index 7816a290..7f9b0f42 100644
> --- a/include/libcamera/internal/v4l2_device.h
> +++ b/include/libcamera/internal/v4l2_device.h
> @@ -17,6 +17,7 @@
>  #include <libcamera/base/signal.h>
>  #include <libcamera/base/span.h>
>
> +#include <libcamera/color_space.h>
>  #include <libcamera/controls.h>
>
>  namespace libcamera {
> @@ -44,6 +45,12 @@ public:
>
>  	void updateControlInfo();
>
> +	template<typename T>
> +	static std::optional<ColorSpace> toColorSpace(const T &v4l2Format);
> +
> +	template<typename T>
> +	static int fromColorSpace(const std::optional<ColorSpace> &colorSpace, T &v4l2Format);
> +

These can be protected

Reviewed-by: Jacopo Mondi <jacopo@jmondi.org>

Thanks
  j

>  protected:
>  	V4L2Device(const std::string &deviceNode);
>  	~V4L2Device();
> diff --git a/src/libcamera/v4l2_device.cpp b/src/libcamera/v4l2_device.cpp
> index 9c783c9c..df92fa9e 100644
> --- a/src/libcamera/v4l2_device.cpp
> +++ b/src/libcamera/v4l2_device.cpp
> @@ -16,6 +16,8 @@
>  #include <sys/syscall.h>
>  #include <unistd.h>
>
> +#include <linux/v4l2-mediabus.h>
> +
>  #include <libcamera/base/event_notifier.h>
>  #include <libcamera/base/log.h>
>  #include <libcamera/base/utils.h>
> @@ -731,4 +733,194 @@ void V4L2Device::eventAvailable()
>  	frameStart.emit(event.u.frame_sync.frame_sequence);
>  }
>
> +static const std::map<uint32_t, ColorSpace> v4l2ToColorSpace = {
> +	{ V4L2_COLORSPACE_RAW, ColorSpace::Raw },
> +	{ V4L2_COLORSPACE_JPEG, ColorSpace::Jpeg },
> +	{ V4L2_COLORSPACE_SRGB, ColorSpace::Srgb },
> +	{ V4L2_COLORSPACE_SMPTE170M, ColorSpace::Smpte170m },
> +	{ V4L2_COLORSPACE_REC709, ColorSpace::Rec709 },
> +	{ V4L2_COLORSPACE_BT2020, ColorSpace::Rec2020 },
> +};
> +
> +static const std::map<uint32_t, ColorSpace::YcbcrEncoding> v4l2ToYcbcrEncoding = {
> +	{ V4L2_YCBCR_ENC_601, ColorSpace::YcbcrEncoding::Rec601 },
> +	{ V4L2_YCBCR_ENC_709, ColorSpace::YcbcrEncoding::Rec709 },
> +	{ V4L2_YCBCR_ENC_BT2020, ColorSpace::YcbcrEncoding::Rec2020 },
> +};
> +
> +static const std::map<uint32_t, ColorSpace::TransferFunction> v4l2ToTransferFunction = {
> +	{ V4L2_XFER_FUNC_NONE, ColorSpace::TransferFunction::Linear },
> +	{ V4L2_XFER_FUNC_SRGB, ColorSpace::TransferFunction::Srgb },
> +	{ V4L2_XFER_FUNC_709, ColorSpace::TransferFunction::Rec709 },
> +};
> +
> +static const std::map<uint32_t, ColorSpace::Range> v4l2ToRange = {
> +	{ V4L2_QUANTIZATION_FULL_RANGE, ColorSpace::Range::Full },
> +	{ V4L2_QUANTIZATION_LIM_RANGE, ColorSpace::Range::Limited },
> +};
> +
> +static const std::vector<std::pair<ColorSpace, v4l2_colorspace>> colorSpaceToV4l2 = {
> +	{ ColorSpace::Raw, V4L2_COLORSPACE_RAW },
> +	{ ColorSpace::Jpeg, V4L2_COLORSPACE_JPEG },
> +	{ ColorSpace::Srgb, V4L2_COLORSPACE_SRGB },
> +	{ ColorSpace::Smpte170m, V4L2_COLORSPACE_SMPTE170M },
> +	{ ColorSpace::Rec709, V4L2_COLORSPACE_REC709 },
> +	{ ColorSpace::Rec2020, V4L2_COLORSPACE_BT2020 },
> +};
> +
> +static const std::map<ColorSpace::Primaries, v4l2_colorspace> primariesToV4l2 = {
> +	{ ColorSpace::Primaries::Raw, V4L2_COLORSPACE_RAW },
> +	{ ColorSpace::Primaries::Smpte170m, V4L2_COLORSPACE_SMPTE170M },
> +	{ ColorSpace::Primaries::Rec709, V4L2_COLORSPACE_REC709 },
> +	{ ColorSpace::Primaries::Rec2020, V4L2_COLORSPACE_BT2020 },
> +};
> +
> +static const std::map<ColorSpace::YcbcrEncoding, v4l2_ycbcr_encoding> ycbcrEncodingToV4l2 = {
> +	{ ColorSpace::YcbcrEncoding::Rec601, V4L2_YCBCR_ENC_601 },
> +	{ ColorSpace::YcbcrEncoding::Rec709, V4L2_YCBCR_ENC_709 },
> +	{ ColorSpace::YcbcrEncoding::Rec2020, V4L2_YCBCR_ENC_BT2020 },
> +};
> +
> +static const std::map<ColorSpace::TransferFunction, v4l2_xfer_func> transferFunctionToV4l2 = {
> +	{ ColorSpace::TransferFunction::Linear, V4L2_XFER_FUNC_NONE },
> +	{ ColorSpace::TransferFunction::Srgb, V4L2_XFER_FUNC_SRGB },
> +	{ ColorSpace::TransferFunction::Rec709, V4L2_XFER_FUNC_709 },
> +};
> +
> +static const std::map<ColorSpace::Range, v4l2_quantization> rangeToV4l2 = {
> +	{ ColorSpace::Range::Full, V4L2_QUANTIZATION_FULL_RANGE },
> +	{ ColorSpace::Range::Limited, V4L2_QUANTIZATION_LIM_RANGE },
> +};
> +
> +/**
> + * \brief Convert the color space fields in a V4L2 format to a ColorSpace
> + * \param[in] v4l2Format A V4L2 format containing color space information
> + *
> + * The colorspace, ycbcr_enc, xfer_func and quantization fields within a
> + * V4L2 format structure are converted to a corresponding ColorSpace.
> + *
> + * If any V4L2 fields are not recognised then we return an "unset"
> + * color space.
> + *
> + * \return The ColorSpace corresponding to the input V4L2 format
> + * \retval std::nullopt One or more V4L2 color space fields were not recognised
> + */
> +template<typename T>
> +std::optional<ColorSpace> V4L2Device::toColorSpace(const T &v4l2Format)
> +{
> +	auto itColor = v4l2ToColorSpace.find(v4l2Format.colorspace);
> +	if (itColor == v4l2ToColorSpace.end())
> +		return std::nullopt;
> +
> +	/* This sets all the color space fields to the correct "default" values. */
> +	ColorSpace colorSpace = itColor->second;
> +
> +	if (v4l2Format.ycbcr_enc != V4L2_YCBCR_ENC_DEFAULT) {
> +		auto itYcbcrEncoding = v4l2ToYcbcrEncoding.find(v4l2Format.ycbcr_enc);
> +		if (itYcbcrEncoding == v4l2ToYcbcrEncoding.end())
> +			return std::nullopt;
> +
> +		colorSpace.ycbcrEncoding = itYcbcrEncoding->second;
> +	}
> +
> +	if (v4l2Format.xfer_func != V4L2_XFER_FUNC_DEFAULT) {
> +		auto itTransfer = v4l2ToTransferFunction.find(v4l2Format.xfer_func);
> +		if (itTransfer == v4l2ToTransferFunction.end())
> +			return std::nullopt;
> +
> +		colorSpace.transferFunction = itTransfer->second;
> +	}
> +
> +	if (v4l2Format.quantization != V4L2_QUANTIZATION_DEFAULT) {
> +		auto itRange = v4l2ToRange.find(v4l2Format.quantization);
> +		if (itRange == v4l2ToRange.end())
> +			return std::nullopt;
> +
> +		colorSpace.range = itRange->second;
> +	}
> +
> +	return colorSpace;
> +}
> +
> +template std::optional<ColorSpace> V4L2Device::toColorSpace(const struct v4l2_pix_format &);
> +template std::optional<ColorSpace> V4L2Device::toColorSpace(const struct v4l2_pix_format_mplane &);
> +template std::optional<ColorSpace> V4L2Device::toColorSpace(const struct v4l2_mbus_framefmt &);
> +
> +/**
> + * \brief Fill in the color space fields of a V4L2 format from a ColorSpace
> + * \param[in] colorSpace The ColorSpace to be converted
> + * \param[out] v4l2Format A V4L2 format containing color space information
> + *
> + * The colorspace, ycbcr_enc, xfer_func and quantization fields within a
> + * V4L2 format structure are filled in from a corresponding ColorSpace.
> + *
> + * An error is returned if any of the V4L2 fields do not support the
> + * value given in the ColorSpace. Such fields are set to the V4L2
> + * "default" values, but all other fields are still filled in where
> + * possible.
> + *
> + * If the color space is completely unset, "default" V4L2 values are used
> + * everywhere, so a driver would then choose its preferred color space.
> + *
> + * \return 0 on success or a negative error code otherwise
> + * \retval -EINVAL The ColorSpace does not have a representation using V4L2 enums
> + */
> +template<typename T>
> +int V4L2Device::fromColorSpace(const std::optional<ColorSpace> &colorSpace, T &v4l2Format)
> +{
> +	v4l2Format.colorspace = V4L2_COLORSPACE_DEFAULT;
> +	v4l2Format.ycbcr_enc = V4L2_YCBCR_ENC_DEFAULT;
> +	v4l2Format.xfer_func = V4L2_XFER_FUNC_DEFAULT;
> +	v4l2Format.quantization = V4L2_QUANTIZATION_DEFAULT;
> +
> +	if (!colorSpace)
> +		return 0;
> +
> +	auto itColor = std::find_if(colorSpaceToV4l2.begin(), colorSpaceToV4l2.end(),
> +				    [&colorSpace](const auto &item) {
> +					    return colorSpace == item.first;
> +				    });
> +	if (itColor != colorSpaceToV4l2.end()) {
> +		v4l2Format.colorspace = itColor->second;
> +		/* Leaving all the other fields as "default" should be fine. */
> +		return 0;
> +	}
> +
> +	/*
> +	 * If the colorSpace doesn't precisely match a standard color space,
> +	 * then we must choose a V4L2 colorspace with matching primaries.
> +	 */
> +	int ret = 0;
> +
> +	auto itPrimaries = primariesToV4l2.find(colorSpace->primaries);
> +	if (itPrimaries != primariesToV4l2.end())
> +		v4l2Format.colorspace = itPrimaries->second;
> +	else
> +		ret = -EINVAL;
> +
> +	auto itYcbcrEncoding = ycbcrEncodingToV4l2.find(colorSpace->ycbcrEncoding);
> +	if (itYcbcrEncoding != ycbcrEncodingToV4l2.end())
> +		v4l2Format.ycbcr_enc = itYcbcrEncoding->second;
> +	else
> +		ret = -EINVAL;
> +
> +	auto itTransfer = transferFunctionToV4l2.find(colorSpace->transferFunction);
> +	if (itTransfer != transferFunctionToV4l2.end())
> +		v4l2Format.xfer_func = itTransfer->second;
> +	else
> +		ret = -EINVAL;
> +
> +	auto itRange = rangeToV4l2.find(colorSpace->range);
> +	if (itRange != rangeToV4l2.end())
> +		v4l2Format.quantization = itRange->second;
> +	else
> +		ret = -EINVAL;
> +
> +	return ret;
> +}
> +
> +template int V4L2Device::fromColorSpace(const std::optional<ColorSpace> &, struct v4l2_pix_format &);
> +template int V4L2Device::fromColorSpace(const std::optional<ColorSpace> &, struct v4l2_pix_format_mplane &);
> +template int V4L2Device::fromColorSpace(const std::optional<ColorSpace> &, struct v4l2_mbus_framefmt &);
> +
>  } /* namespace libcamera */
> --
> 2.30.2
>
David Plowman Dec. 1, 2021, 11:50 a.m. UTC | #2 
Hi Jacopo

Thanks for the review!

On Tue, 30 Nov 2021 at 21:10, Jacopo Mondi <jacopo@jmondi.org> wrote:
>
> Hi David
>
> On Fri, Nov 26, 2021 at 10:40:41AM +0000, David Plowman wrote:
> > Add functions to the V4L2Device class to convert to and from
> > libcamera ColorSpace.
> >
> > These methods are added to the base V4L2Device class so that they can
> > be shared both by the video device class and subdevices.
> >
> > With the ColorSpace class, the color space and related other fields
> > are stored together, corresponding to a number of fields in the
> > various different V4L2 format structures. Template methods are
> > therefore a convenient implementation, and we must explicitly
> > instantiate the templates that will be needed.
> >
> > Note that unset color spaces are converted to requests for the
> > device's "default" color space.
> >
> > Signed-off-by: David Plowman <david.plowman@raspberrypi.com>
> > ---
> >  include/libcamera/internal/v4l2_device.h |   7 +
> >  src/libcamera/v4l2_device.cpp            | 192 +++++++++++++++++++++++
> >  2 files changed, 199 insertions(+)
> >
> > diff --git a/include/libcamera/internal/v4l2_device.h b/include/libcamera/internal/v4l2_device.h
> > index 7816a290..7f9b0f42 100644
> > --- a/include/libcamera/internal/v4l2_device.h
> > +++ b/include/libcamera/internal/v4l2_device.h
> > @@ -17,6 +17,7 @@
> >  #include <libcamera/base/signal.h>
> >  #include <libcamera/base/span.h>
> >
> > +#include <libcamera/color_space.h>
> >  #include <libcamera/controls.h>
> >
> >  namespace libcamera {
> > @@ -44,6 +45,12 @@ public:
> >
> >       void updateControlInfo();
> >
> > +     template<typename T>
> > +     static std::optional<ColorSpace> toColorSpace(const T &v4l2Format);
> > +
> > +     template<typename T>
> > +     static int fromColorSpace(const std::optional<ColorSpace> &colorSpace, T &v4l2Format);
> > +
>
> These can be protected

So the only reason I didn't do this was that I could envisage pipeline
handlers wanting to check if their chosen colour space is known to
V4L2. I know that can't happen at the moment, but there is a possible
future with new or custom colour spaces... But that's all a bit
hypothetical, so maybe it's better to make them protected now and
change it back later if we ever want to?

But I don't feel strongly - happy to change this if folks prefer it that way!

Thanks
David

>
> Reviewed-by: Jacopo Mondi <jacopo@jmondi.org>
>
> Thanks
>   j
>
> >  protected:
> >       V4L2Device(const std::string &deviceNode);
> >       ~V4L2Device();
> > diff --git a/src/libcamera/v4l2_device.cpp b/src/libcamera/v4l2_device.cpp
> > index 9c783c9c..df92fa9e 100644
> > --- a/src/libcamera/v4l2_device.cpp
> > +++ b/src/libcamera/v4l2_device.cpp
> > @@ -16,6 +16,8 @@
> >  #include <sys/syscall.h>
> >  #include <unistd.h>
> >
> > +#include <linux/v4l2-mediabus.h>
> > +
> >  #include <libcamera/base/event_notifier.h>
> >  #include <libcamera/base/log.h>
> >  #include <libcamera/base/utils.h>
> > @@ -731,4 +733,194 @@ void V4L2Device::eventAvailable()
> >       frameStart.emit(event.u.frame_sync.frame_sequence);
> >  }
> >
> > +static const std::map<uint32_t, ColorSpace> v4l2ToColorSpace = {
> > +     { V4L2_COLORSPACE_RAW, ColorSpace::Raw },
> > +     { V4L2_COLORSPACE_JPEG, ColorSpace::Jpeg },
> > +     { V4L2_COLORSPACE_SRGB, ColorSpace::Srgb },
> > +     { V4L2_COLORSPACE_SMPTE170M, ColorSpace::Smpte170m },
> > +     { V4L2_COLORSPACE_REC709, ColorSpace::Rec709 },
> > +     { V4L2_COLORSPACE_BT2020, ColorSpace::Rec2020 },
> > +};
> > +
> > +static const std::map<uint32_t, ColorSpace::YcbcrEncoding> v4l2ToYcbcrEncoding = {
> > +     { V4L2_YCBCR_ENC_601, ColorSpace::YcbcrEncoding::Rec601 },
> > +     { V4L2_YCBCR_ENC_709, ColorSpace::YcbcrEncoding::Rec709 },
> > +     { V4L2_YCBCR_ENC_BT2020, ColorSpace::YcbcrEncoding::Rec2020 },
> > +};
> > +
> > +static const std::map<uint32_t, ColorSpace::TransferFunction> v4l2ToTransferFunction = {
> > +     { V4L2_XFER_FUNC_NONE, ColorSpace::TransferFunction::Linear },
> > +     { V4L2_XFER_FUNC_SRGB, ColorSpace::TransferFunction::Srgb },
> > +     { V4L2_XFER_FUNC_709, ColorSpace::TransferFunction::Rec709 },
> > +};
> > +
> > +static const std::map<uint32_t, ColorSpace::Range> v4l2ToRange = {
> > +     { V4L2_QUANTIZATION_FULL_RANGE, ColorSpace::Range::Full },
> > +     { V4L2_QUANTIZATION_LIM_RANGE, ColorSpace::Range::Limited },
> > +};
> > +
> > +static const std::vector<std::pair<ColorSpace, v4l2_colorspace>> colorSpaceToV4l2 = {
> > +     { ColorSpace::Raw, V4L2_COLORSPACE_RAW },
> > +     { ColorSpace::Jpeg, V4L2_COLORSPACE_JPEG },
> > +     { ColorSpace::Srgb, V4L2_COLORSPACE_SRGB },
> > +     { ColorSpace::Smpte170m, V4L2_COLORSPACE_SMPTE170M },
> > +     { ColorSpace::Rec709, V4L2_COLORSPACE_REC709 },
> > +     { ColorSpace::Rec2020, V4L2_COLORSPACE_BT2020 },
> > +};
> > +
> > +static const std::map<ColorSpace::Primaries, v4l2_colorspace> primariesToV4l2 = {
> > +     { ColorSpace::Primaries::Raw, V4L2_COLORSPACE_RAW },
> > +     { ColorSpace::Primaries::Smpte170m, V4L2_COLORSPACE_SMPTE170M },
> > +     { ColorSpace::Primaries::Rec709, V4L2_COLORSPACE_REC709 },
> > +     { ColorSpace::Primaries::Rec2020, V4L2_COLORSPACE_BT2020 },
> > +};
> > +
> > +static const std::map<ColorSpace::YcbcrEncoding, v4l2_ycbcr_encoding> ycbcrEncodingToV4l2 = {
> > +     { ColorSpace::YcbcrEncoding::Rec601, V4L2_YCBCR_ENC_601 },
> > +     { ColorSpace::YcbcrEncoding::Rec709, V4L2_YCBCR_ENC_709 },
> > +     { ColorSpace::YcbcrEncoding::Rec2020, V4L2_YCBCR_ENC_BT2020 },
> > +};
> > +
> > +static const std::map<ColorSpace::TransferFunction, v4l2_xfer_func> transferFunctionToV4l2 = {
> > +     { ColorSpace::TransferFunction::Linear, V4L2_XFER_FUNC_NONE },
> > +     { ColorSpace::TransferFunction::Srgb, V4L2_XFER_FUNC_SRGB },
> > +     { ColorSpace::TransferFunction::Rec709, V4L2_XFER_FUNC_709 },
> > +};
> > +
> > +static const std::map<ColorSpace::Range, v4l2_quantization> rangeToV4l2 = {
> > +     { ColorSpace::Range::Full, V4L2_QUANTIZATION_FULL_RANGE },
> > +     { ColorSpace::Range::Limited, V4L2_QUANTIZATION_LIM_RANGE },
> > +};
> > +
> > +/**
> > + * \brief Convert the color space fields in a V4L2 format to a ColorSpace
> > + * \param[in] v4l2Format A V4L2 format containing color space information
> > + *
> > + * The colorspace, ycbcr_enc, xfer_func and quantization fields within a
> > + * V4L2 format structure are converted to a corresponding ColorSpace.
> > + *
> > + * If any V4L2 fields are not recognised then we return an "unset"
> > + * color space.
> > + *
> > + * \return The ColorSpace corresponding to the input V4L2 format
> > + * \retval std::nullopt One or more V4L2 color space fields were not recognised
> > + */
> > +template<typename T>
> > +std::optional<ColorSpace> V4L2Device::toColorSpace(const T &v4l2Format)
> > +{
> > +     auto itColor = v4l2ToColorSpace.find(v4l2Format.colorspace);
> > +     if (itColor == v4l2ToColorSpace.end())
> > +             return std::nullopt;
> > +
> > +     /* This sets all the color space fields to the correct "default" values. */
> > +     ColorSpace colorSpace = itColor->second;
> > +
> > +     if (v4l2Format.ycbcr_enc != V4L2_YCBCR_ENC_DEFAULT) {
> > +             auto itYcbcrEncoding = v4l2ToYcbcrEncoding.find(v4l2Format.ycbcr_enc);
> > +             if (itYcbcrEncoding == v4l2ToYcbcrEncoding.end())
> > +                     return std::nullopt;
> > +
> > +             colorSpace.ycbcrEncoding = itYcbcrEncoding->second;
> > +     }
> > +
> > +     if (v4l2Format.xfer_func != V4L2_XFER_FUNC_DEFAULT) {
> > +             auto itTransfer = v4l2ToTransferFunction.find(v4l2Format.xfer_func);
> > +             if (itTransfer == v4l2ToTransferFunction.end())
> > +                     return std::nullopt;
> > +
> > +             colorSpace.transferFunction = itTransfer->second;
> > +     }
> > +
> > +     if (v4l2Format.quantization != V4L2_QUANTIZATION_DEFAULT) {
> > +             auto itRange = v4l2ToRange.find(v4l2Format.quantization);
> > +             if (itRange == v4l2ToRange.end())
> > +                     return std::nullopt;
> > +
> > +             colorSpace.range = itRange->second;
> > +     }
> > +
> > +     return colorSpace;
> > +}
> > +
> > +template std::optional<ColorSpace> V4L2Device::toColorSpace(const struct v4l2_pix_format &);
> > +template std::optional<ColorSpace> V4L2Device::toColorSpace(const struct v4l2_pix_format_mplane &);
> > +template std::optional<ColorSpace> V4L2Device::toColorSpace(const struct v4l2_mbus_framefmt &);
> > +
> > +/**
> > + * \brief Fill in the color space fields of a V4L2 format from a ColorSpace
> > + * \param[in] colorSpace The ColorSpace to be converted
> > + * \param[out] v4l2Format A V4L2 format containing color space information
> > + *
> > + * The colorspace, ycbcr_enc, xfer_func and quantization fields within a
> > + * V4L2 format structure are filled in from a corresponding ColorSpace.
> > + *
> > + * An error is returned if any of the V4L2 fields do not support the
> > + * value given in the ColorSpace. Such fields are set to the V4L2
> > + * "default" values, but all other fields are still filled in where
> > + * possible.
> > + *
> > + * If the color space is completely unset, "default" V4L2 values are used
> > + * everywhere, so a driver would then choose its preferred color space.
> > + *
> > + * \return 0 on success or a negative error code otherwise
> > + * \retval -EINVAL The ColorSpace does not have a representation using V4L2 enums
> > + */
> > +template<typename T>
> > +int V4L2Device::fromColorSpace(const std::optional<ColorSpace> &colorSpace, T &v4l2Format)
> > +{
> > +     v4l2Format.colorspace = V4L2_COLORSPACE_DEFAULT;
> > +     v4l2Format.ycbcr_enc = V4L2_YCBCR_ENC_DEFAULT;
> > +     v4l2Format.xfer_func = V4L2_XFER_FUNC_DEFAULT;
> > +     v4l2Format.quantization = V4L2_QUANTIZATION_DEFAULT;
> > +
> > +     if (!colorSpace)
> > +             return 0;
> > +
> > +     auto itColor = std::find_if(colorSpaceToV4l2.begin(), colorSpaceToV4l2.end(),
> > +                                 [&colorSpace](const auto &item) {
> > +                                         return colorSpace == item.first;
> > +                                 });
> > +     if (itColor != colorSpaceToV4l2.end()) {
> > +             v4l2Format.colorspace = itColor->second;
> > +             /* Leaving all the other fields as "default" should be fine. */
> > +             return 0;
> > +     }
> > +
> > +     /*
> > +      * If the colorSpace doesn't precisely match a standard color space,
> > +      * then we must choose a V4L2 colorspace with matching primaries.
> > +      */
> > +     int ret = 0;
> > +
> > +     auto itPrimaries = primariesToV4l2.find(colorSpace->primaries);
> > +     if (itPrimaries != primariesToV4l2.end())
> > +             v4l2Format.colorspace = itPrimaries->second;
> > +     else
> > +             ret = -EINVAL;
> > +
> > +     auto itYcbcrEncoding = ycbcrEncodingToV4l2.find(colorSpace->ycbcrEncoding);
> > +     if (itYcbcrEncoding != ycbcrEncodingToV4l2.end())
> > +             v4l2Format.ycbcr_enc = itYcbcrEncoding->second;
> > +     else
> > +             ret = -EINVAL;
> > +
> > +     auto itTransfer = transferFunctionToV4l2.find(colorSpace->transferFunction);
> > +     if (itTransfer != transferFunctionToV4l2.end())
> > +             v4l2Format.xfer_func = itTransfer->second;
> > +     else
> > +             ret = -EINVAL;
> > +
> > +     auto itRange = rangeToV4l2.find(colorSpace->range);
> > +     if (itRange != rangeToV4l2.end())
> > +             v4l2Format.quantization = itRange->second;
> > +     else
> > +             ret = -EINVAL;
> > +
> > +     return ret;
> > +}
> > +
> > +template int V4L2Device::fromColorSpace(const std::optional<ColorSpace> &, struct v4l2_pix_format &);
> > +template int V4L2Device::fromColorSpace(const std::optional<ColorSpace> &, struct v4l2_pix_format_mplane &);
> > +template int V4L2Device::fromColorSpace(const std::optional<ColorSpace> &, struct v4l2_mbus_framefmt &);
> > +
> >  } /* namespace libcamera */
> > --
> > 2.30.2
> >

Patch
diff mbox series 

diff --git a/include/libcamera/internal/v4l2_device.h b/include/libcamera/internal/v4l2_device.h
index 7816a290..7f9b0f42 100644
--- a/include/libcamera/internal/v4l2_device.h
+++ b/include/libcamera/internal/v4l2_device.h
@@ -17,6 +17,7 @@ 
 #include <libcamera/base/signal.h>
 #include <libcamera/base/span.h>
 
+#include <libcamera/color_space.h>
 #include <libcamera/controls.h>
 
 namespace libcamera {
@@ -44,6 +45,12 @@  public:
 
 	void updateControlInfo();
 
+	template<typename T>
+	static std::optional<ColorSpace> toColorSpace(const T &v4l2Format);
+
+	template<typename T>
+	static int fromColorSpace(const std::optional<ColorSpace> &colorSpace, T &v4l2Format);
+
 protected:
 	V4L2Device(const std::string &deviceNode);
 	~V4L2Device();
diff --git a/src/libcamera/v4l2_device.cpp b/src/libcamera/v4l2_device.cpp
index 9c783c9c..df92fa9e 100644
--- a/src/libcamera/v4l2_device.cpp
+++ b/src/libcamera/v4l2_device.cpp
@@ -16,6 +16,8 @@ 
 #include <sys/syscall.h>
 #include <unistd.h>
 
+#include <linux/v4l2-mediabus.h>
+
 #include <libcamera/base/event_notifier.h>
 #include <libcamera/base/log.h>
 #include <libcamera/base/utils.h>
@@ -731,4 +733,194 @@  void V4L2Device::eventAvailable()
 	frameStart.emit(event.u.frame_sync.frame_sequence);
 }
 
+static const std::map<uint32_t, ColorSpace> v4l2ToColorSpace = {
+	{ V4L2_COLORSPACE_RAW, ColorSpace::Raw },
+	{ V4L2_COLORSPACE_JPEG, ColorSpace::Jpeg },
+	{ V4L2_COLORSPACE_SRGB, ColorSpace::Srgb },
+	{ V4L2_COLORSPACE_SMPTE170M, ColorSpace::Smpte170m },
+	{ V4L2_COLORSPACE_REC709, ColorSpace::Rec709 },
+	{ V4L2_COLORSPACE_BT2020, ColorSpace::Rec2020 },
+};
+
+static const std::map<uint32_t, ColorSpace::YcbcrEncoding> v4l2ToYcbcrEncoding = {
+	{ V4L2_YCBCR_ENC_601, ColorSpace::YcbcrEncoding::Rec601 },
+	{ V4L2_YCBCR_ENC_709, ColorSpace::YcbcrEncoding::Rec709 },
+	{ V4L2_YCBCR_ENC_BT2020, ColorSpace::YcbcrEncoding::Rec2020 },
+};
+
+static const std::map<uint32_t, ColorSpace::TransferFunction> v4l2ToTransferFunction = {
+	{ V4L2_XFER_FUNC_NONE, ColorSpace::TransferFunction::Linear },
+	{ V4L2_XFER_FUNC_SRGB, ColorSpace::TransferFunction::Srgb },
+	{ V4L2_XFER_FUNC_709, ColorSpace::TransferFunction::Rec709 },
+};
+
+static const std::map<uint32_t, ColorSpace::Range> v4l2ToRange = {
+	{ V4L2_QUANTIZATION_FULL_RANGE, ColorSpace::Range::Full },
+	{ V4L2_QUANTIZATION_LIM_RANGE, ColorSpace::Range::Limited },
+};
+
+static const std::vector<std::pair<ColorSpace, v4l2_colorspace>> colorSpaceToV4l2 = {
+	{ ColorSpace::Raw, V4L2_COLORSPACE_RAW },
+	{ ColorSpace::Jpeg, V4L2_COLORSPACE_JPEG },
+	{ ColorSpace::Srgb, V4L2_COLORSPACE_SRGB },
+	{ ColorSpace::Smpte170m, V4L2_COLORSPACE_SMPTE170M },
+	{ ColorSpace::Rec709, V4L2_COLORSPACE_REC709 },
+	{ ColorSpace::Rec2020, V4L2_COLORSPACE_BT2020 },
+};
+
+static const std::map<ColorSpace::Primaries, v4l2_colorspace> primariesToV4l2 = {
+	{ ColorSpace::Primaries::Raw, V4L2_COLORSPACE_RAW },
+	{ ColorSpace::Primaries::Smpte170m, V4L2_COLORSPACE_SMPTE170M },
+	{ ColorSpace::Primaries::Rec709, V4L2_COLORSPACE_REC709 },
+	{ ColorSpace::Primaries::Rec2020, V4L2_COLORSPACE_BT2020 },
+};
+
+static const std::map<ColorSpace::YcbcrEncoding, v4l2_ycbcr_encoding> ycbcrEncodingToV4l2 = {
+	{ ColorSpace::YcbcrEncoding::Rec601, V4L2_YCBCR_ENC_601 },
+	{ ColorSpace::YcbcrEncoding::Rec709, V4L2_YCBCR_ENC_709 },
+	{ ColorSpace::YcbcrEncoding::Rec2020, V4L2_YCBCR_ENC_BT2020 },
+};
+
+static const std::map<ColorSpace::TransferFunction, v4l2_xfer_func> transferFunctionToV4l2 = {
+	{ ColorSpace::TransferFunction::Linear, V4L2_XFER_FUNC_NONE },
+	{ ColorSpace::TransferFunction::Srgb, V4L2_XFER_FUNC_SRGB },
+	{ ColorSpace::TransferFunction::Rec709, V4L2_XFER_FUNC_709 },
+};
+
+static const std::map<ColorSpace::Range, v4l2_quantization> rangeToV4l2 = {
+	{ ColorSpace::Range::Full, V4L2_QUANTIZATION_FULL_RANGE },
+	{ ColorSpace::Range::Limited, V4L2_QUANTIZATION_LIM_RANGE },
+};
+
+/**
+ * \brief Convert the color space fields in a V4L2 format to a ColorSpace
+ * \param[in] v4l2Format A V4L2 format containing color space information
+ *
+ * The colorspace, ycbcr_enc, xfer_func and quantization fields within a
+ * V4L2 format structure are converted to a corresponding ColorSpace.
+ *
+ * If any V4L2 fields are not recognised then we return an "unset"
+ * color space.
+ *
+ * \return The ColorSpace corresponding to the input V4L2 format
+ * \retval std::nullopt One or more V4L2 color space fields were not recognised
+ */
+template<typename T>
+std::optional<ColorSpace> V4L2Device::toColorSpace(const T &v4l2Format)
+{
+	auto itColor = v4l2ToColorSpace.find(v4l2Format.colorspace);
+	if (itColor == v4l2ToColorSpace.end())
+		return std::nullopt;
+
+	/* This sets all the color space fields to the correct "default" values. */
+	ColorSpace colorSpace = itColor->second;
+
+	if (v4l2Format.ycbcr_enc != V4L2_YCBCR_ENC_DEFAULT) {
+		auto itYcbcrEncoding = v4l2ToYcbcrEncoding.find(v4l2Format.ycbcr_enc);
+		if (itYcbcrEncoding == v4l2ToYcbcrEncoding.end())
+			return std::nullopt;
+
+		colorSpace.ycbcrEncoding = itYcbcrEncoding->second;
+	}
+
+	if (v4l2Format.xfer_func != V4L2_XFER_FUNC_DEFAULT) {
+		auto itTransfer = v4l2ToTransferFunction.find(v4l2Format.xfer_func);
+		if (itTransfer == v4l2ToTransferFunction.end())
+			return std::nullopt;
+
+		colorSpace.transferFunction = itTransfer->second;
+	}
+
+	if (v4l2Format.quantization != V4L2_QUANTIZATION_DEFAULT) {
+		auto itRange = v4l2ToRange.find(v4l2Format.quantization);
+		if (itRange == v4l2ToRange.end())
+			return std::nullopt;
+
+		colorSpace.range = itRange->second;
+	}
+
+	return colorSpace;
+}
+
+template std::optional<ColorSpace> V4L2Device::toColorSpace(const struct v4l2_pix_format &);
+template std::optional<ColorSpace> V4L2Device::toColorSpace(const struct v4l2_pix_format_mplane &);
+template std::optional<ColorSpace> V4L2Device::toColorSpace(const struct v4l2_mbus_framefmt &);
+
+/**
+ * \brief Fill in the color space fields of a V4L2 format from a ColorSpace
+ * \param[in] colorSpace The ColorSpace to be converted
+ * \param[out] v4l2Format A V4L2 format containing color space information
+ *
+ * The colorspace, ycbcr_enc, xfer_func and quantization fields within a
+ * V4L2 format structure are filled in from a corresponding ColorSpace.
+ *
+ * An error is returned if any of the V4L2 fields do not support the
+ * value given in the ColorSpace. Such fields are set to the V4L2
+ * "default" values, but all other fields are still filled in where
+ * possible.
+ *
+ * If the color space is completely unset, "default" V4L2 values are used
+ * everywhere, so a driver would then choose its preferred color space.
+ *
+ * \return 0 on success or a negative error code otherwise
+ * \retval -EINVAL The ColorSpace does not have a representation using V4L2 enums
+ */
+template<typename T>
+int V4L2Device::fromColorSpace(const std::optional<ColorSpace> &colorSpace, T &v4l2Format)
+{
+	v4l2Format.colorspace = V4L2_COLORSPACE_DEFAULT;
+	v4l2Format.ycbcr_enc = V4L2_YCBCR_ENC_DEFAULT;
+	v4l2Format.xfer_func = V4L2_XFER_FUNC_DEFAULT;
+	v4l2Format.quantization = V4L2_QUANTIZATION_DEFAULT;
+
+	if (!colorSpace)
+		return 0;
+
+	auto itColor = std::find_if(colorSpaceToV4l2.begin(), colorSpaceToV4l2.end(),
+				    [&colorSpace](const auto &item) {
+					    return colorSpace == item.first;
+				    });
+	if (itColor != colorSpaceToV4l2.end()) {
+		v4l2Format.colorspace = itColor->second;
+		/* Leaving all the other fields as "default" should be fine. */
+		return 0;
+	}
+
+	/*
+	 * If the colorSpace doesn't precisely match a standard color space,
+	 * then we must choose a V4L2 colorspace with matching primaries.
+	 */
+	int ret = 0;
+
+	auto itPrimaries = primariesToV4l2.find(colorSpace->primaries);
+	if (itPrimaries != primariesToV4l2.end())
+		v4l2Format.colorspace = itPrimaries->second;
+	else
+		ret = -EINVAL;
+
+	auto itYcbcrEncoding = ycbcrEncodingToV4l2.find(colorSpace->ycbcrEncoding);
+	if (itYcbcrEncoding != ycbcrEncodingToV4l2.end())
+		v4l2Format.ycbcr_enc = itYcbcrEncoding->second;
+	else
+		ret = -EINVAL;
+
+	auto itTransfer = transferFunctionToV4l2.find(colorSpace->transferFunction);
+	if (itTransfer != transferFunctionToV4l2.end())
+		v4l2Format.xfer_func = itTransfer->second;
+	else
+		ret = -EINVAL;
+
+	auto itRange = rangeToV4l2.find(colorSpace->range);
+	if (itRange != rangeToV4l2.end())
+		v4l2Format.quantization = itRange->second;
+	else
+		ret = -EINVAL;
+
+	return ret;
+}
+
+template int V4L2Device::fromColorSpace(const std::optional<ColorSpace> &, struct v4l2_pix_format &);
+template int V4L2Device::fromColorSpace(const std::optional<ColorSpace> &, struct v4l2_pix_format_mplane &);
+template int V4L2Device::fromColorSpace(const std::optional<ColorSpace> &, struct v4l2_mbus_framefmt &);
+
 } /* namespace libcamera */