[libcamera-devel] [PATCH v2 16/16] libcamera: pipeline: uvcvideo: Add format information and validation

[Niklas Söderlund]

Hi Jacopo,

Thanks for your feedback.

On 2019-06-13 19:30:10 +0200, Jacopo Mondi wrote:
> Hi Niklas,
> 
> On Wed, Jun 12, 2019 at 02:43:59AM +0200, Niklas Söderlund wrote:
> > Extend the uvcvideo pipeline with format information and validation. The
> > format information is gathered by enumerating the v4l2 device. This
> > enumeration approach is valid for UVC as it has a static and simple
> > media graph.
> >
> > Signed-off-by: Niklas Söderlund <niklas.soderlund at ragnatech.se>
> > ---
> >  src/libcamera/pipeline/uvcvideo.cpp | 41 ++++++++++++++++++++++-------
> >  1 file changed, 31 insertions(+), 10 deletions(-)
> >
> > diff --git a/src/libcamera/pipeline/uvcvideo.cpp b/src/libcamera/pipeline/uvcvideo.cpp
> > index 45260f34c8f5daba..7ca9d0eefe8223e8 100644
> > --- a/src/libcamera/pipeline/uvcvideo.cpp
> > +++ b/src/libcamera/pipeline/uvcvideo.cpp
> > @@ -5,6 +5,8 @@
> >   * uvcvideo.cpp - Pipeline handler for uvcvideo devices
> >   */
> >
> > +#include <algorithm>
> > +
> >  #include <libcamera/camera.h>
> >  #include <libcamera/request.h>
> >  #include <libcamera/stream.h>
> > @@ -95,18 +97,33 @@ CameraConfiguration::Status UVCCameraConfiguration::validate()
> >  	}
> >
> >  	StreamConfiguration &cfg = config_[0];
> > -
> > -	/* \todo: Validate the configuration against the device capabilities. */
> > +	const StreamFormats &formats = cfg.formats();
> >  	const unsigned int pixelFormat = cfg.pixelFormat;
> >  	const Size size = cfg.size;
> >
> > -	cfg.pixelFormat = V4L2_PIX_FMT_YUYV;
> > -	cfg.size = { 640, 480 };
> > +	const std::vector<unsigned int> pixelFormats = formats.pixelformats();
> > +	auto iter = std::find(pixelFormats.begin(), pixelFormats.end(), pixelFormat);
> > +	if (iter == pixelFormats.end()) {
> > +		cfg.pixelFormat = pixelFormats.front();
> > +		LOG(UVC, Debug)
> > +			<< "Adjusting pixel format from " << pixelFormat
> > +			<< " to " << cfg.pixelFormat;
> > +		status = Adjusted;
> > +	}
> > +
> > +	const std::vector<Size> &formatSizes = formats.sizes(cfg.pixelFormat);
> > +	cfg.size = formatSizes.front();
> > +	for (const Size &formatsSize : formatSizes) {
> > +		if (formatsSize > size)
> > +			break;
> > +
> > +		cfg.size = formatsSize;
> > +	}
> 
> Even this selects not the closest size, but the smallest closest one, I
> think it's fine for now.

Yes, closes smallest one is selected, I think that is fine for now.

> >
> > -	if (cfg.pixelFormat != pixelFormat || cfg.size != size) {
> > +	if (cfg.size != size) {
> >  		LOG(UVC, Debug)
> > -			<< "Adjusting configuration from " << cfg.toString()
> > -			<< " to " << cfg.size.toString() << "-YUYV";
> > +			<< "Adjusting size from " << size.toString()
> > +			<< " to " << cfg.size.toString();
> >  		status = Adjusted;
> >  	}
> >
> > @@ -123,14 +140,18 @@ PipelineHandlerUVC::PipelineHandlerUVC(CameraManager *manager)
> >  CameraConfiguration *PipelineHandlerUVC::generateConfiguration(Camera *camera,
> >  	const StreamRoles &roles)
> >  {
> > +	UVCCameraData *data = cameraData(camera);
> >  	CameraConfiguration *config = new UVCCameraConfiguration();
> >
> >  	if (roles.empty())
> >  		return config;
> >
> > -	StreamConfiguration cfg{};
> > -	cfg.pixelFormat = V4L2_PIX_FMT_YUYV;
> > -	cfg.size = { 640, 480 };
> > +	ImageFormats v4l2formats = data->video_->formats();
> > +	StreamFormats formats(v4l2formats.data());
> 
> Do we want to be able to construct a StreamFormat from an ImageFormat?

I don't think so. I think it's a special case for UVC where the 
StreamFormats will be built directly from the ImageFormats. If I'm wrong 
and this will turn into a common thing I would agree that this would be 
neat.

> 
> 
> Minors apart
> Reviewed-by: Jacopo Mondi <jacopo at jmondi.org>
> 
> Thanks
>   j
> 
> > +	StreamConfiguration cfg(formats);
> > +
> > +	cfg.pixelFormat = formats.pixelformats().front();
> > +	cfg.size = formats.sizes(cfg.pixelFormat).back();
> >  	cfg.bufferCount = 4;
> >
> >  	config->addConfiguration(cfg);
> > --
> > 2.21.0
> >
> > _______________________________________________
> > libcamera-devel mailing list
> > libcamera-devel at lists.libcamera.org
> > https://lists.libcamera.org/listinfo/libcamera-devel



-- 
Regards,
Niklas Söderlund