[libcamera-devel] [PATCH v4 08/21] v4l2: v4l2_camera_proxy: Use stream config in tryFormat

[Jacopo Mondi]

Hi Paul,

On Wed, Jul 08, 2020 at 10:44:04PM +0900, Paul Elder wrote:
> For handling try_fmt, the values should be filled in by validating the
> stream configuration, and not by recalculating them or manually checking
> against the cached list of formats and sizes. Use
> V4L2Camera::validateConfiguration to obtain size, format, stride, and
> frameSize values. Also, implement this function in V4L2Camera.
>
> Signed-off-by: Paul Elder <paul.elder at ideasonboard.com>
>
> ---
> Changes in v4:
> - clean up code a bit
> - squash the implementation and usage
>
> New in v3
> ---
>  src/v4l2/v4l2_camera.cpp       | 20 ++++++++++++++++++++
>  src/v4l2/v4l2_camera.h         |  3 +++
>  src/v4l2/v4l2_camera_proxy.cpp | 23 +++++++++--------------
>  3 files changed, 32 insertions(+), 14 deletions(-)
>
> diff --git a/src/v4l2/v4l2_camera.cpp b/src/v4l2/v4l2_camera.cpp
> index ffc1230..9f81c97 100644
> --- a/src/v4l2/v4l2_camera.cpp
> +++ b/src/v4l2/v4l2_camera.cpp
> @@ -138,6 +138,26 @@ int V4L2Camera::configure(StreamConfiguration *streamConfigOut,
>  	return 0;
>  }
>
> +int V4L2Camera::validateConfiguration(const PixelFormat &pixelFormat,

I'm not familiar with this part of the code, nor I have a full
understanding of the series yet, so maybe there's alreay a
generateConfiguration() or has been introduced, but this function
seems to that does not validate a configuration with filled fields,
but rather generates a valid one.

If its purpose is to validate a configuration it should then take a
const StreamConfiguration & and return its status, or an error code.

If it should instead generate a valid StreamConfiguration I would
rename that and make it return a StreamConfiguration

> +				      const Size &size,
> +				      StreamConfiguration *streamConfigOut)
> +{
> +	std::unique_ptr<CameraConfiguration> config =
> +		camera_->generateConfiguration({ StreamRole::Viewfinder });
> +	StreamConfiguration &cfg = config->at(0);
> +	cfg.size = size;
> +	cfg.pixelFormat = pixelFormat;
> +	cfg.bufferCount = 1;
> +
> +	CameraConfiguration::Status validation = config->validate();
> +	if (validation == CameraConfiguration::Invalid)
> +		return -EINVAL;
> +
> +	*streamConfigOut = cfg;
> +
> +	return 0;
> +}
> +
>  int V4L2Camera::allocBuffers(unsigned int count)
>  {
>  	Stream *stream = *camera_->streams().begin();
> diff --git a/src/v4l2/v4l2_camera.h b/src/v4l2/v4l2_camera.h
> index 515e906..be6c4e1 100644
> --- a/src/v4l2/v4l2_camera.h
> +++ b/src/v4l2/v4l2_camera.h
> @@ -47,6 +47,9 @@ public:
>  	int configure(StreamConfiguration *streamConfigOut,
>  		      const Size &size, const PixelFormat &pixelformat,
>  		      unsigned int bufferCount);
> +	int validateConfiguration(const PixelFormat &pixelformat,
> +				  const Size &size,
> +				  StreamConfiguration *streamConfigOut);
>
>  	int allocBuffers(unsigned int count);
>  	void freeBuffers();
> diff --git a/src/v4l2/v4l2_camera_proxy.cpp b/src/v4l2/v4l2_camera_proxy.cpp
> index 305ede0..5c92ff7 100644
> --- a/src/v4l2/v4l2_camera_proxy.cpp
> +++ b/src/v4l2/v4l2_camera_proxy.cpp
> @@ -300,24 +300,19 @@ void V4L2CameraProxy::tryFormat(struct v4l2_format *arg)
>  {
>  	V4L2PixelFormat v4l2Format = V4L2PixelFormat(arg->fmt.pix.pixelformat);
>  	PixelFormat format = PixelFormatInfo::info(v4l2Format).format;
> -	const std::vector<PixelFormat> &formats =
> -		streamConfig_.formats().pixelformats();
> -	if (std::find(formats.begin(), formats.end(), format) == formats.end())
> -		format = streamConfig_.formats().pixelformats()[0];
> -
>  	Size size(arg->fmt.pix.width, arg->fmt.pix.height);
> -	const std::vector<Size> &sizes = streamConfig_.formats().sizes(format);
> -	if (std::find(sizes.begin(), sizes.end(), size) == sizes.end())
> -		size = streamConfig_.formats().sizes(format)[0];
>
> -	const PixelFormatInfo &formatInfo = PixelFormatInfo::info(format);
> +	StreamConfiguration config;
> +	vcam_->validateConfiguration(format, size, &config);

Shouldn't you check if it's valid ? maybe it's done later on.

> +
> +	const PixelFormatInfo &info = PixelFormatInfo::info(config.pixelFormat);
>
> -	arg->fmt.pix.width        = size.width;
> -	arg->fmt.pix.height       = size.height;
> -	arg->fmt.pix.pixelformat  = formatInfo.v4l2Format;
> +	arg->fmt.pix.width        = config.size.width;
> +	arg->fmt.pix.height       = config.size.height;
> +	arg->fmt.pix.pixelformat  = info.v4l2Format;
>  	arg->fmt.pix.field        = V4L2_FIELD_NONE;
> -	arg->fmt.pix.bytesperline = formatInfo.stride(size.width, 0);
> -	arg->fmt.pix.sizeimage    = formatInfo.frameSize(size);
> +	arg->fmt.pix.bytesperline = config.stride;
> +	arg->fmt.pix.sizeimage    = config.frameSize;
>  	arg->fmt.pix.colorspace   = V4L2_COLORSPACE_SRGB;
>  	arg->fmt.pix.priv         = V4L2_PIX_FMT_PRIV_MAGIC;
>  	arg->fmt.pix.ycbcr_enc    = V4L2_YCBCR_ENC_DEFAULT;
> --
> 2.27.0
>
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