[PATCH v2 6/8] libcamera: converter_v4l2_m2m: Improve crop bounds support

[Jacopo Mondi]

On Mon, Nov 25, 2024 at 04:14:15PM +0100, Stefan Klug wrote:
> When a converter (dw100 on imx8mp in this case) is used in a pipeline,
> the ScalerCrop control get's created at createCamera() time. As this is

Kind of unrelated to this patch, right ? :)

> before configure(), no streams were configured on the converter and the
> stream specific crop bounds are not known. Extend the converter class to
> report the default crop bounds in case the provided stream is not found.
>
> Signed-off-by: Stefan Klug <stefan.klug at ideasonboard.com>
> ---
> Changes in v2:
> - Added this patch
> ---
>  .../internal/converter/converter_v4l2_m2m.h   |   1 +
>  src/libcamera/converter.cpp                   |   3 +
>  .../converter/converter_v4l2_m2m.cpp          | 113 +++++++++---------
>  3 files changed, 59 insertions(+), 58 deletions(-)
>
> diff --git a/include/libcamera/internal/converter/converter_v4l2_m2m.h b/include/libcamera/internal/converter/converter_v4l2_m2m.h
> index 0bc0d053e2c4..a5286166f574 100644
> --- a/include/libcamera/internal/converter/converter_v4l2_m2m.h
> +++ b/include/libcamera/internal/converter/converter_v4l2_m2m.h
> @@ -105,6 +105,7 @@ private:
>
>  	std::map<const Stream *, std::unique_ptr<V4L2M2MStream>> streams_;
>  	std::map<FrameBuffer *, unsigned int> queue_;
> +	std::pair<Rectangle, Rectangle> inputCropBounds_;
>  };
>
>  } /* namespace libcamera */
> diff --git a/src/libcamera/converter.cpp b/src/libcamera/converter.cpp
> index 945f2527b96a..d4b5e5260e02 100644
> --- a/src/libcamera/converter.cpp
> +++ b/src/libcamera/converter.cpp
> @@ -195,6 +195,9 @@ Converter::~Converter()
>   * this function should be called after the \a stream has been configured using
>   * configure().
>   *
> + * When called with an invalid \a stream, the function returns the default crop
> + * bounds of the converter.
> + *
>   * \return A pair containing the minimum and maximum crop bound in that order
>   */
>
> diff --git a/src/libcamera/converter/converter_v4l2_m2m.cpp b/src/libcamera/converter/converter_v4l2_m2m.cpp
> index d63ef2f8028f..bd7e5cce600d 100644
> --- a/src/libcamera/converter/converter_v4l2_m2m.cpp
> +++ b/src/libcamera/converter/converter_v4l2_m2m.cpp
> @@ -30,6 +30,52 @@ namespace libcamera {
>
>  LOG_DECLARE_CATEGORY(Converter)
>
> +namespace {
> +
> +int getCropBounds(V4L2VideoDevice *device, Rectangle &minCrop,
> +		  Rectangle &maxCrop)
> +{
> +	Rectangle minC;
> +	Rectangle maxC;
> +
> +	/* Find crop bounds */
> +	minC.width = 1;
> +	minC.height = 1;
> +	maxC.width = UINT_MAX;
> +	maxC.height = UINT_MAX;
> +
> +	int ret = device->setSelection(V4L2_SEL_TGT_CROP, &minC);
> +	if (ret) {
> +		LOG(Converter, Error)
> +			<< "Could not query minimum selection crop: "
> +			<< strerror(-ret);
> +		return ret;
> +	}
> +
> +	ret = device->getSelection(V4L2_SEL_TGT_CROP_BOUNDS, &maxC);
> +	if (ret) {
> +		LOG(Converter, Error)
> +			<< "Could not query maximum selection crop: "
> +			<< strerror(-ret);
> +		return ret;
> +	}
> +
> +	/* Reset the crop to its maximum */
> +	ret = device->setSelection(V4L2_SEL_TGT_CROP, &maxC);
> +	if (ret) {
> +		LOG(Converter, Error)
> +			<< "Could not reset selection crop: "
> +			<< strerror(-ret);
> +		return ret;
> +	}
> +
> +	minCrop = minC;
> +	maxCrop = maxC;
> +	return 0;
> +}
> +
> +} /* namespace */
> +
>  /* -----------------------------------------------------------------------------
>   * V4L2M2MConverter::V4L2M2MStream
>   */
> @@ -98,41 +144,10 @@ int V4L2M2MConverter::V4L2M2MStream::configure(const StreamConfiguration &inputC
>  	outputBufferCount_ = outputCfg.bufferCount;
>
>  	if (converter_->features() & Feature::InputCrop) {
> -		Rectangle minCrop;
> -		Rectangle maxCrop;
> -
> -		/* Find crop bounds */
> -		minCrop.width = 1;
> -		minCrop.height = 1;
> -		maxCrop.width = UINT_MAX;
> -		maxCrop.height = UINT_MAX;
> -
> -		ret = setInputSelection(V4L2_SEL_TGT_CROP, &minCrop);
> -		if (ret) {
> -			LOG(Converter, Error)
> -				<< "Could not query minimum selection crop: "
> -				<< strerror(-ret);
> -			return ret;
> -		}
> -
> -		ret = getInputSelection(V4L2_SEL_TGT_CROP_BOUNDS, &maxCrop);
> -		if (ret) {
> -			LOG(Converter, Error)
> -				<< "Could not query maximum selection crop: "
> -				<< strerror(-ret);
> -			return ret;
> -		}
> -
> -		/* Reset the crop to its maximum */
> -		ret = setInputSelection(V4L2_SEL_TGT_CROP, &maxCrop);
> -		if (ret) {
> -			LOG(Converter, Error)
> -				<< "Could not reset selection crop: "
> -				<< strerror(-ret);

Maybe I don't understand M2M enough, but is there of Stream-specific
here ?

There's an output and an input queue, right ? Do they have per-stream
crop bounds ??

> +		ret = getCropBounds(m2m_->output(), inputCropBounds_.first,
> +				    inputCropBounds_.second);
> +		if (ret)
>  			return ret;
> -		}
> -
> -		inputCropBounds_ = { minCrop, maxCrop };
>  	}
>
>  	return 0;
> @@ -258,27 +273,9 @@ V4L2M2MConverter::V4L2M2MConverter(MediaDevice *media)
>  		return;
>  	}
>
> -	/* Discover Feature::InputCrop */
> -	Rectangle maxCrop;
> -	maxCrop.width = UINT_MAX;
> -	maxCrop.height = UINT_MAX;
> -
> -	ret = m2m_->output()->setSelection(V4L2_SEL_TGT_CROP, &maxCrop);
> -	if (ret)
> -		return;
> -
> -	/*
> -	 * Rectangles for cropping targets are defined even if the device
> -	 * does not support cropping. Their sizes and positions will be
> -	 * fixed in such cases.
> -	 *
> -	 * Set and inspect a crop equivalent to half of the maximum crop
> -	 * returned earlier. Use this to determine whether the crop on
> -	 * input is really supported.
> -	 */
> -	Rectangle halfCrop(maxCrop.size() / 2);
> -	ret = m2m_->output()->setSelection(V4L2_SEL_TGT_CROP, &halfCrop);
> -	if (!ret && halfCrop != maxCrop) {
> +	ret = getCropBounds(m2m_->output(), inputCropBounds_.first,
> +			    inputCropBounds_.second);
> +	if (!ret && inputCropBounds_.first != inputCropBounds_.second) {
>  		features_ |= Feature::InputCrop;
>
>  		LOG(Converter, Info)
> @@ -477,10 +474,10 @@ std::pair<Rectangle, Rectangle>
>  V4L2M2MConverter::inputCropBounds(const Stream *stream)
>  {
>  	auto iter = streams_.find(stream);
> -	if (iter == streams_.end())
> -		return {};
> +	if (iter != streams_.end())
> +		return iter->second->inputCropBounds();
>
> -	return iter->second->inputCropBounds();
> +	return inputCropBounds_;
>  }
>
>  /**
> --
> 2.43.0
>