[libcamera-devel] [PATCH 1/2] libcamera: v4l2-format: Add V4L2DeviceFormat

[Kieran Bingham]

Hi Jacopo,

On 28/01/2019 15:11, Jacopo Mondi wrote:
> Add a V4L2DeviceFormat class aimed to be used to provide format configuration
> requests to a V4L2Device.
> 
> Signed-off-by: Jacopo Mondi <jacopo at jmondi.org>

Reviewed-by: Kieran Bingham <kieran.bingham at ideasonboard.com>

> ---
>  src/libcamera/include/v4l2_device.h | 14 ++++++++
>  src/libcamera/v4l2_device.cpp       | 56 +++++++++++++++++++++++++++++
>  2 files changed, 70 insertions(+)
> 
> diff --git a/src/libcamera/include/v4l2_device.h b/src/libcamera/include/v4l2_device.h
> index c67ebbf..c70959e 100644
> --- a/src/libcamera/include/v4l2_device.h
> +++ b/src/libcamera/include/v4l2_device.h
> @@ -53,6 +53,20 @@ struct V4L2Capability final : v4l2_capability {
>  	}
>  };
>  
> +class V4L2DeviceFormat
> +{
> +public:
> +	uint32_t width;
> +	uint32_t height;
> +	uint32_t fourcc;

I might have called this pixelFormat, but it's internal and it can
change if we later define a PixelFormat class or such.

Currently we will store a fourcc so this is accurate.

> +
> +	struct {
> +		uint32_t size;
> +		uint32_t bpl;
> +	} planesFmt[3];
> +	unsigned int planes;
> +};
> +
>  class MediaEntity;
>  class V4L2Device
>  {
> diff --git a/src/libcamera/v4l2_device.cpp b/src/libcamera/v4l2_device.cpp
> index 408f9b9..d6143f2 100644
> --- a/src/libcamera/v4l2_device.cpp
> +++ b/src/libcamera/v4l2_device.cpp
> @@ -80,6 +80,62 @@ LOG_DEFINE_CATEGORY(V4L2)
>   * \return True if the device provides Streaming I/O IOCTLs
>   */
>  
> +/**
> + * \class V4L2DeviceFormat
> + * \brief The V4L2 device image format and sizes
> + *
> + * Describes the image format and image sizes to be programmed on a V4L2
> + * video device. The image format is defined by fourcc code as defined by
> + * the V4L2 APIs with the V4L2_PIX_FMT_ macros, a visible width and height
> + * and a variable number of planes (1 to 3) with variable sizes and line
> + * strides.
> + *
> + * Formats defined as 'single planar' by the V4L2 APIs are represented with
> + * V4L2DeviceFormat instances with a single plane
> + * (V4L2DeviceFormat::planes = 1). Semi-planar and multiplanar formats use
> + * 2 and 3 planes respectively.
> + *
> + * V4L2DeviceFormat defines the exchange format between components that
> + * receive image configuration requests from applications and a V4L2Device.
> + * The V4L2Device validates and applies the requested size and format to
> + * the device driver.
> + */
> +
> +/**
> + * \var V4L2DeviceFormat::width
> + * \brief The image width
> + */
> +
> +/**
> + * \var V4L2DeviceFormat::height
> + * \brief The image height
> + */
> +
> +/**
> + * \var V4L2DeviceFormat::fourcc> + * \brief The pixel encoding scheme
> + *
> + * The fourcc code, as defined by the V4L2 APIs with the V4L2_PIX_FMT_ macros,
> + * that identifies the image format pixel encoding scheme.
> + */
> +
> +/**
> + * \var V4L2DeviceFormat::planesFmt
> + * \brief The per-plane size information
> + *
> + * Images are stored in memory in one or more data planes. Each data plane
> + * has a specific size and line length, which could differ from the image
> + * visible sizes to accommodate line or plane padding data.
> + *
> + * Only the first V4L2DeviceFormat::planes entries are considered valid.
> + *
> + */
> +
> +/**
> + * \var V4L2DeviceFormat::planes
> + * \brief The number of valid data planes
> + */
> +
>  /**
>   * \class V4L2Device
>   * \brief V4L2Device object and API
> 

-- 
Regards
--
Kieran