[libcamera-devel] [PATCH v2 3/9] libcamera: bayer_format: Add support for mbus codes
Laurent Pinchart
laurent.pinchart at ideasonboard.com
Tue Dec 22 12:35:11 CET 2020
Hi Jacopo,
Thank you for the patch.
On Fri, Dec 18, 2020 at 05:47:48PM +0100, Jacopo Mondi wrote:
> The existing implementation of the BayerFormat class supports
> converting a V4L2PixelFormat to a BayerFormat and vice-versa.
>
> Expand the class by adding support for converting a media bus code
> to a BayerFormat instance, by providing a conversion table and a
> dedicated constructor.
>
> Expand the number of supported compression and expand the documentation.
>
> Do not provide support for converting a BayerFormat to a media bus code
> as the feature is currently not required.
And the mapping would be 1:1 anyway. That's the issue with media bus
codes, they don't have a 1:1 mapping to pixel formats.
> Signed-off-by: Jacopo Mondi <jacopo at jmondi.org>
> ---
> include/libcamera/internal/bayer_format.h | 3 ++
> src/libcamera/bayer_format.cpp | 66 ++++++++++++++++++++++-
> 2 files changed, 68 insertions(+), 1 deletion(-)
>
> diff --git a/include/libcamera/internal/bayer_format.h b/include/libcamera/internal/bayer_format.h
> index 4280b76b016f..7d7539e275ff 100644
> --- a/include/libcamera/internal/bayer_format.h
> +++ b/include/libcamera/internal/bayer_format.h
> @@ -30,6 +30,8 @@ public:
> None = 0,
> CSI2Packed = 1,
> IPU3Packed = 2,
> + ALAW8Compression = 3,
> + DPCM8Compression = 4,
Compression and packing are not mutually exclusive, this would need to
become flags, or possibly get moved to a separate enum.
> };
>
> constexpr BayerFormat()
> @@ -43,6 +45,7 @@ public:
> }
>
> explicit BayerFormat(V4L2PixelFormat v4l2Format);
> + explicit BayerFormat(unsigned int mbusCode);
> bool isValid() const { return bitDepth != 0; }
>
> std::string toString() const;
> diff --git a/src/libcamera/bayer_format.cpp b/src/libcamera/bayer_format.cpp
> index c42792ff1948..a4eba4592bfe 100644
> --- a/src/libcamera/bayer_format.cpp
> +++ b/src/libcamera/bayer_format.cpp
> @@ -8,6 +8,9 @@
> #include "libcamera/internal/bayer_format.h"
>
> #include <map>
> +#include <unordered_map>
> +
> +#include <linux/media-bus-format.h>
>
> #include <libcamera/transform.h>
>
> @@ -45,7 +48,8 @@ namespace libcamera {
>
> /**
> * \enum BayerFormat::Packing
> - * \brief Different types of packing that can be applied to a BayerFormat
> + * \brief Different types of packing or compressions that can be applied to a
> + * BayerFormat
> *
> * \var BayerFormat::None
> * \brief No packing
> @@ -53,6 +57,10 @@ namespace libcamera {
> * \brief Format uses MIPI CSI-2 style packing
> * \var BayerFormat::IPU3Packed
> * \brief Format uses IPU3 style packing
> + * \var BayerFormat::ALAW8Compression
> + * \brief Format uses ALAW8 compression
> + * \var BayerFormat::DPCM8Compression
> + * \brief Format uses DPCM8 compression
> */
>
> namespace {
> @@ -140,6 +148,41 @@ const std::map<BayerFormat, V4L2PixelFormat, BayerFormatComparator> bayerToV4l2{
> { { BayerFormat::RGGB, 16, BayerFormat::None }, V4L2PixelFormat(V4L2_PIX_FMT_SRGGB16) },
> };
>
> +const std::unordered_map<unsigned int, BayerFormat> mbusCodeToBayer{
> + { MEDIA_BUS_FMT_SBGGR8_1X8, { BayerFormat::BGGR, 8, BayerFormat::None } },
> + { MEDIA_BUS_FMT_SGBRG8_1X8, { BayerFormat::GBRG, 8, BayerFormat::None } },
> + { MEDIA_BUS_FMT_SGRBG8_1X8, { BayerFormat::GRBG, 8, BayerFormat::None } },
> + { MEDIA_BUS_FMT_SRGGB8_1X8, { BayerFormat::RGGB, 8, BayerFormat::None } },
> + { MEDIA_BUS_FMT_SBGGR10_ALAW8_1X8, { BayerFormat::BGGR, 8, BayerFormat::ALAW8Compression } },
> + { MEDIA_BUS_FMT_SGBRG10_ALAW8_1X8, { BayerFormat::GBRG, 8, BayerFormat::ALAW8Compression } },
> + { MEDIA_BUS_FMT_SGRBG10_ALAW8_1X8, { BayerFormat::GRBG, 8, BayerFormat::ALAW8Compression } },
> + { MEDIA_BUS_FMT_SRGGB10_ALAW8_1X8, { BayerFormat::RGGB, 8, BayerFormat::ALAW8Compression } },
> + { MEDIA_BUS_FMT_SBGGR10_DPCM8_1X8, { BayerFormat::BGGR, 8, BayerFormat::DPCM8Compression } },
> + { MEDIA_BUS_FMT_SGBRG10_DPCM8_1X8, { BayerFormat::GBRG, 8, BayerFormat::DPCM8Compression } },
> + { MEDIA_BUS_FMT_SGRBG10_DPCM8_1X8, { BayerFormat::GRBG, 8, BayerFormat::DPCM8Compression } },
> + { MEDIA_BUS_FMT_SRGGB10_DPCM8_1X8, { BayerFormat::RGGB, 8, BayerFormat::DPCM8Compression } },
> + { MEDIA_BUS_FMT_SBGGR10_2X8_PADHI_BE, { BayerFormat::BGGR, 10, BayerFormat::None } },
> + { MEDIA_BUS_FMT_SBGGR10_2X8_PADHI_LE, { BayerFormat::BGGR, 10, BayerFormat::None } },
> + { MEDIA_BUS_FMT_SBGGR10_2X8_PADLO_BE, { BayerFormat::BGGR, 10, BayerFormat::None } },
> + { MEDIA_BUS_FMT_SBGGR10_2X8_PADLO_LE, { BayerFormat::BGGR, 10, BayerFormat::None } },
> + { MEDIA_BUS_FMT_SBGGR10_1X10, { BayerFormat::BGGR, 10, BayerFormat::None } },
> + { MEDIA_BUS_FMT_SGBRG10_1X10, { BayerFormat::GBRG, 10, BayerFormat::None } },
> + { MEDIA_BUS_FMT_SGRBG10_1X10, { BayerFormat::GRBG, 10, BayerFormat::None } },
> + { MEDIA_BUS_FMT_SRGGB10_1X10, { BayerFormat::RGGB, 10, BayerFormat::None } },
> + { MEDIA_BUS_FMT_SBGGR12_1X12, { BayerFormat::BGGR, 12, BayerFormat::None } },
> + { MEDIA_BUS_FMT_SGBRG12_1X12, { BayerFormat::GBRG, 12, BayerFormat::None } },
> + { MEDIA_BUS_FMT_SGRBG12_1X12, { BayerFormat::GRBG, 12, BayerFormat::None } },
> + { MEDIA_BUS_FMT_SRGGB12_1X12, { BayerFormat::RGGB, 12, BayerFormat::None } },
> + { MEDIA_BUS_FMT_SBGGR14_1X14, { BayerFormat::BGGR, 14, BayerFormat::None } },
> + { MEDIA_BUS_FMT_SGBRG14_1X14, { BayerFormat::GBRG, 14, BayerFormat::None } },
> + { MEDIA_BUS_FMT_SGRBG14_1X14, { BayerFormat::GRBG, 14, BayerFormat::None } },
> + { MEDIA_BUS_FMT_SRGGB14_1X14, { BayerFormat::RGGB, 14, BayerFormat::None } },
> + { MEDIA_BUS_FMT_SBGGR16_1X16, { BayerFormat::BGGR, 16, BayerFormat::None } },
> + { MEDIA_BUS_FMT_SGBRG16_1X16, { BayerFormat::GBRG, 16, BayerFormat::None } },
> + { MEDIA_BUS_FMT_SGRBG16_1X16, { BayerFormat::GRBG, 16, BayerFormat::None } },
> + { MEDIA_BUS_FMT_SRGGB16_1X16, { BayerFormat::RGGB, 16, BayerFormat::None } },
> +};
> +
> } /* namespace */
>
> /**
> @@ -169,6 +212,22 @@ BayerFormat::BayerFormat(V4L2PixelFormat v4l2Format)
> *this = it->second;
> }
>
> +/**
> + * \brief Construct a BayerFormat from a media bus code
> + * \param[in] mbusCode The media bus code to convert into a BayerFormat
> + *
> + * The media bus code numeric identifiers are defined by the V4L2 specification.
> + */
> +BayerFormat::BayerFormat(unsigned int mbusCode)
> + : order(BGGR), packing(None)
> +{
> + const auto it = mbusCodeToBayer.find(mbusCode);
> + if (it == mbusCodeToBayer.end())
> + bitDepth = 0;
> + else
> + *this = it->second;
> +}
Instead of a constructor, wouldn't a static
BayerFormat::fromMediaBusCode() function be better ? The trouble with a
constructor is that, as it has to take an unsigned int argument (we
don't have a media bus code class), one could write
BayerFormat format(V4L2_PIX_FMT_YUYV);
and the compiler wouldn't complain. Worse, PixelFormat::operator
uint32_t() isn't explicit, so
PixelFormat pf(...);
BayerFormat format(pf);
will also compile.
Obviously,
PixelFormat pf(...);
BayerFormat format = BayerFormat::fromMediaBusCode(pf);
will also compile, but it will be easier to spot from the code that
something is wrong.
> +
> /**
> * \fn BayerFormat::isValid()
> * \brief Return whether a BayerFormat is valid
> @@ -258,6 +317,11 @@ BayerFormat BayerFormat::transform(Transform t) const
> /**
> * \var BayerFormat::bitDepth
> * \brief The bit depth of the samples in the Bayer pattern
> + *
> + * For formats using compression schemes such as Packing::ALAW8Compression or
> + * Packing::DPCM8Compression, the bitDepth value refers to the size of the
> + * sample when transmitted on the wire or stored into memory. The resulting
> + * images need to be de-compressed to be viewed properly.
> */
>
> /**
--
Regards,
Laurent Pinchart
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