[libcamera-devel] [PATCH v2 02/12] android: camera_device: Generate JPEG sizes

[Jacopo Mondi]

Hi Laurent,

On Sat, Sep 05, 2020 at 08:49:01PM +0300, Laurent Pinchart wrote:
> Hi Jacopo,
>
> Thank you for the patch.
>
> On Wed, Sep 02, 2020 at 05:22:26PM +0200, Jacopo Mondi wrote:
> > When producing the list of image resolution to claim as supported by the
>
> s/resolution/resolutions/
>
> > camera HAL, the JPEG stream was assumed to be 'always valid' as, at the
> > time, there was no JPEG support in place at all.
> >
> > With the introduction of support for JPEG compression, reporting
> > non-valid sizes as supported obviously causes troubles.
> >
> > In order to avoid reporting non-supported resolutions as supported,
> > produce the list of available JPEG sizes by using the ones supported
> > by the YCbCr_420_888 format, from which the JPEG stream is encoded.
>
> Down the line we'll likely need to scale down images for JPEG
> compression, but for now this looks fine to me.
>
> > Reviewed-by: Kieran Bingham <kieran.bingham at ideasonboard.com>
> > Signed-off-by: Jacopo Mondi <jacopo at jmondi.org>
> > ---
> >  src/android/camera_device.cpp | 43 +++++++++++++++++++++++------------
> >  1 file changed, 28 insertions(+), 15 deletions(-)
> >
> > diff --git a/src/android/camera_device.cpp b/src/android/camera_device.cpp
> > index ad0d7fd15d90..8a8072123961 100644
> > --- a/src/android/camera_device.cpp
> > +++ b/src/android/camera_device.cpp
> > @@ -363,17 +363,27 @@ int CameraDevice::initializeStreamConfigurations()
> >  		const std::vector<PixelFormat> &libcameraFormats =
> >  			camera3Format.libcameraFormats;
> >
> > +		/*
> > +		 * Fixed format mapping for JPEG.
> > +		 *
> > +		 * The list of supported JPEG resolutions is generated
> > +		 * from the list of resolutions supported by
> > +		 * HAL_PIXEL_FORMAT_YCbCr_420_888 from which JPEG is produced.
>
> This doesn seem to correspond to the code below. Should it read

doesn't it ? JPEG is generated from YCbCr... but this comment is
actually a repetition of another one here below, so I guess I can
replace it.

>
> 		/*
> 		 * JPEG is always supported, either produced directly by the
> 		 * camera, or encoded in the HAL.
> 		 */
>
> ?
>
> > +		 *
> > +		 * \todo Wire the JPEG encoder interface to query the list
> > +		 * of supported resolutions.
>
> Is this still valid ?
>

I think so. As explained to Kieran in v1 I think all the
implementation of the Encoder interface should be able to return the
list of supported resolution to take into account things like, say,
alignment.

> > +		 */
> > +		if (androidFormat == HAL_PIXEL_FORMAT_BLOB) {
> > +			formatsMap_[androidFormat] = formats::MJPEG;
> > +			continue;
> > +		}
> > +
> >  		/*
> >  		 * Test the libcamera formats that can produce images
> >  		 * compatible with the format defined by Android.
> >  		 */
> >  		PixelFormat mappedFormat;
> >  		for (const PixelFormat &pixelFormat : libcameraFormats) {
> > -			/* \todo Fixed mapping for JPEG. */
> > -			if (androidFormat == HAL_PIXEL_FORMAT_BLOB) {
> > -				mappedFormat = formats::MJPEG;
> > -				break;
> > -			}
> >
> >  			/*
> >  			 * The stream configuration size can be adjusted,
> > @@ -416,19 +426,22 @@ int CameraDevice::initializeStreamConfigurations()
> >  			cfg.size = res;
> >
> >  			CameraConfiguration::Status status = cameraConfig->validate();
> > -			/*
> > -			 * Unconditionally report we can produce JPEG.
> > -			 *
> > -			 * \todo The JPEG stream will be implemented as an
> > -			 * HAL-only stream, but some cameras can produce it
> > -			 * directly. As of now, claim support for JPEG without
> > -			 * inspecting where the JPEG stream is produced.
> > -			 */
> > -			if (androidFormat != HAL_PIXEL_FORMAT_BLOB &&
> > -			    status != CameraConfiguration::Valid)
> > +			if (status != CameraConfiguration::Valid)
> >  				continue;
> >
> >  			streamConfigurations_.push_back({ res, androidFormat });
> > +
> > +			/*
> > +			 * If the format is HAL_PIXEL_FORMAT_YCbCr_420_888
> > +			 * from which JPEG is produced, add an entry for
> > +			 * the JPEG stream.
> > +			 *
> > +			 * \todo Wire the JPEG encoder to query the supported
> > +			 * sizes provided a list of formats it can encode.
>
> We shouldn't do this if the device can provide JPEG natively. Is this
> something you'd like to address already ? Otherwise we should add a
> \todo item for this too.

This isn't different from what we had before. I we want to support
JPEG natively produced from the camera, there's some work to do to
identify that at the beginning of this function.

A todo item is indeed appropriate.

Thanks
  j

>
> > +			 */
> > +			if (androidFormat == HAL_PIXEL_FORMAT_YCbCr_420_888)
> > +				streamConfigurations_.push_back(
> > +					{ res, HAL_PIXEL_FORMAT_BLOB });
> >  		}
> >  	}
> >
>
> --
> Regards,
>
> Laurent Pinchart