[libcamera-devel] [PATCH 09/17] libcamera: v4l2_device: Add enumeration of pixelformats and frame sizes

[Kieran Bingham]

Hi Niklas,

On 27/05/2019 01:15, Niklas Söderlund wrote:
> Add methods to enumerate pixelformats and frame sizes from a v4l2
> device. The interface is similar to how V4L2Subdevice enumerates mbus
> codes and frame sizes.
> 

Could we add a test or two to test/v4l2_device/formats.cpp for this
public API addition?

> Signed-off-by: Niklas Söderlund <niklas.soderlund at ragnatech.se>
> ---
>  src/libcamera/include/v4l2_device.h |   5 ++
>  src/libcamera/v4l2_device.cpp       | 104 ++++++++++++++++++++++++++++
>  2 files changed, 109 insertions(+)
> 
> diff --git a/src/libcamera/include/v4l2_device.h b/src/libcamera/include/v4l2_device.h
> index 2e7bd1e7f4cce276..db2d12757c6f564a 100644
> --- a/src/libcamera/include/v4l2_device.h
> +++ b/src/libcamera/include/v4l2_device.h
> @@ -16,6 +16,7 @@
>  #include <libcamera/geometry.h>
>  #include <libcamera/signal.h>
>  
> +#include "formats.h"
>  #include "log.h"
>  
>  namespace libcamera {
> @@ -126,6 +127,7 @@ public:
>  
>  	int getFormat(V4L2DeviceFormat *format);
>  	int setFormat(V4L2DeviceFormat *format);
> +	V4L2DeviceFormats formats();
>  
>  	int exportBuffers(BufferPool *pool);
>  	int importBuffers(BufferPool *pool);
> @@ -154,6 +156,9 @@ private:
>  	int createPlane(Buffer *buffer, unsigned int plane,
>  			unsigned int length);
>  
> +	std::vector<unsigned int> enumPixelformats();
> +	std::vector<SizeRange> enumSizes(unsigned int pixelformat);
> +
>  	Buffer *dequeueBuffer();
>  	void bufferAvailable(EventNotifier *notifier);
>  
> diff --git a/src/libcamera/v4l2_device.cpp b/src/libcamera/v4l2_device.cpp
> index 8366ffc4db559520..a9667092a20505d9 100644
> --- a/src/libcamera/v4l2_device.cpp
> +++ b/src/libcamera/v4l2_device.cpp
> @@ -564,6 +564,23 @@ int V4L2Device::setFormatMultiplane(V4L2DeviceFormat *format)
>  	return 0;
>  }
>  
> +/**
> + * \brief Enumerate all pixelformats and frame sizes
> + *
> + * Enumerate all pixelformats and frame sizes reported by the video device.
> + *
> + * \return All pixelformats and frame sizes

How about:

 \return A list of the supported device formats

<except s/list/some-other-type-description/ >

> + */
> +V4L2DeviceFormats V4L2Device::formats()

Eeep, we have a V4L2DeviceFormat class and a V4L2DeviceFormats class
which do (somewhat) different things ...

I hope that won't be too confusing... <I've gone back and noted this in
reply to the patch that adds the types.>


> +{
> +	std::map<unsigned int, std::vector<SizeRange>> formatMap = {};
> +
> +	for (unsigned int pixelformat : enumPixelformats())
> +		formatMap[pixelformat] = enumSizes(pixelformat);
> +
> +	return V4L2DeviceFormats(formatMap);
> +}
> +
>  int V4L2Device::requestBuffers(unsigned int count)
>  {
>  	struct v4l2_requestbuffers rb = {};
> @@ -692,6 +709,93 @@ int V4L2Device::createPlane(Buffer *buffer, unsigned int planeIndex,
>  
>  	return 0;
>  }

newline required here.

> +std::vector<unsigned int> V4L2Device::enumPixelformats()
> +{
> +	std::vector<unsigned int> pixelformats;
> +	int ret;
> +
> +	for (unsigned int index = 0;; index++) {
> +		struct v4l2_fmtdesc pixelformatEnum = {
> +			.index = index,
> +			.type = bufferType_,
> +		};
> +
> +		ret = ioctl(fd_, VIDIOC_ENUM_FMT, &pixelformatEnum);
> +		if (ret)
> +			break;
> +
> +		pixelformats.push_back(pixelformatEnum.pixelformat);
> +	}
> +
> +	if (ret && errno != EINVAL) {
> +		ret = errno;
> +		LOG(V4L2, Error)
> +			<< "Unable to enumerate pixelformats: "
> +			<< strerror(ret);
> +		return {};
> +	}
> +
> +	return pixelformats;
> +}
> +
> +std::vector<SizeRange> V4L2Device::enumSizes(unsigned int pixelformat)
> +{
> +	std::vector<SizeRange> sizes;
> +	int ret;
> +
> +	for (unsigned int index = 0;; index++) {
> +		struct v4l2_frmsizeenum frameSize = {
> +			.index = index,
> +			.pixel_format = pixelformat,
> +		};
> +
> +		ret = ioctl(fd_, VIDIOC_ENUM_FRAMESIZES, &frameSize);
> +		if (ret)
> +			break;
> +
> +		if (index != 0 &&
> +		    frameSize.type != V4L2_FRMSIZE_TYPE_DISCRETE) {
> +			LOG(V4L2, Error)
> +				<< "None 0 index for none discrete type";

Non-zero index for non discrete type

> +			return {};
> +		}
> +
> +		switch (frameSize.type) {
> +		case V4L2_FRMSIZE_TYPE_DISCRETE:
> +			sizes.emplace_back(frameSize.discrete.width,
> +					   frameSize.discrete.height);
> +			break;
> +		case V4L2_FRMSIZE_TYPE_CONTINUOUS:
> +			sizes.emplace_back(frameSize.stepwise.min_width,
> +					   frameSize.stepwise.min_height,
> +					   frameSize.stepwise.max_width,
> +					   frameSize.stepwise.max_height);
> +			break;
> +		case V4L2_FRMSIZE_TYPE_STEPWISE:
> +			sizes.emplace_back(frameSize.stepwise.min_width,
> +					   frameSize.stepwise.min_height,
> +					   frameSize.stepwise.max_width,
> +					   frameSize.stepwise.max_height,
> +					   frameSize.stepwise.step_width,
> +					   frameSize.stepwise.step_height);
> +			break;
> +		default:
> +			LOG(V4L2, Error)
> +				<< "Unkown VIDIOC_ENUM_FRAMESIZES type "

s/Unkown/Unknown/

> +				<< frameSize.type;
> +			return {};
> +		}
> +	}
> +
> +	if (ret && errno != EINVAL) {
> +		ret = errno;
> +		LOG(V4L2, Error)
> +			<< "Unable to enumerate frame sizes: " << strerror(ret);
> +		return {};
> +	}
> +
> +	return sizes;
> +}
>  
>  /**
>   * \brief Import the externally allocated \a pool of buffers
> 

-- 
Regards
--
Kieran