[libcamera-devel] [PATCH v3 20/30] android: jpeg: Support multi-planar buffers

[Kieran Bingham]

On 06/09/2021 23:56, Laurent Pinchart wrote:
> The JPEG post-processor uses MappedFrameBuffer to access pixel data, but
> only uses data from the first plane. Pass the vector of planes to the
> encode() function to correctly handle multi-planar formats (currently
> limited to NV12).
> 
> Signed-off-by: Laurent Pinchart <laurent.pinchart at ideasonboard.com>
> Acked-by: Umang Jain <umang.jain at ideasonboard.com>
> Tested-by: Umang Jain <umang.jain at ideasonboard.com>
> Reviewed-by: Hirokazu Honda <hiroh at chromium.org>
> ---
>  src/android/jpeg/encoder_libjpeg.cpp     | 17 +++++++++--------
>  src/android/jpeg/encoder_libjpeg.h       |  8 +++++---
>  src/android/jpeg/post_processor_jpeg.cpp |  2 +-
>  src/android/jpeg/thumbnailer.cpp         |  4 ++--
>  4 files changed, 17 insertions(+), 14 deletions(-)
> 
> diff --git a/src/android/jpeg/encoder_libjpeg.cpp b/src/android/jpeg/encoder_libjpeg.cpp
> index 807a0949a8fc..d0b1da5016d2 100644
> --- a/src/android/jpeg/encoder_libjpeg.cpp
> +++ b/src/android/jpeg/encoder_libjpeg.cpp
> @@ -103,9 +103,9 @@ int EncoderLibJpeg::configure(const StreamConfiguration &cfg)
>  	return 0;
>  }
>  
> -void EncoderLibJpeg::compressRGB(Span<const uint8_t> frame)
> +void EncoderLibJpeg::compressRGB(const std::vector<Span<uint8_t>> &planes)
>  {
> -	unsigned char *src = const_cast<unsigned char *>(frame.data());
> +	unsigned char *src = const_cast<unsigned char *>(planes[0].data());
>  	/* \todo Stride information should come from buffer configuration. */
>  	unsigned int stride = pixelFormatInfo_->stride(compress_.image_width, 0);
>  
> @@ -121,7 +121,7 @@ void EncoderLibJpeg::compressRGB(Span<const uint8_t> frame)
>   * Compress the incoming buffer from a supported NV format.
>   * This naively unpacks the semi-planar NV12 to a YUV888 format for libjpeg.
>   */
> -void EncoderLibJpeg::compressNV(Span<const uint8_t> frame)
> +void EncoderLibJpeg::compressNV(const std::vector<Span<uint8_t>> &planes)
>  {

Should we ASSERT(planes.size() >= 2); here? (or even == 2?)

>  	uint8_t tmprowbuf[compress_.image_width * 3];
>  
> @@ -143,8 +143,8 @@ void EncoderLibJpeg::compressNV(Span<const uint8_t> frame)
>  	unsigned int cb_pos = nvSwap_ ? 1 : 0;
>  	unsigned int cr_pos = nvSwap_ ? 0 : 1;
>  
> -	const unsigned char *src = frame.data();
> -	const unsigned char *src_c = src + y_stride * compress_.image_height;
> +	const unsigned char *src = planes[0].data();
> +	const unsigned char *src_c = planes[1].data();
>  
>  	JSAMPROW row_pointer[1];
>  	row_pointer[0] = &tmprowbuf[0];
> @@ -188,11 +188,12 @@ int EncoderLibJpeg::encode(const FrameBuffer &source, Span<uint8_t> dest,
>  		return frame.error();
>  	}
>  
> -	return encode(frame.planes()[0], dest, exifData, quality);
> +	return encode(frame.planes(), dest, exifData, quality);
>  }
>  
> -int EncoderLibJpeg::encode(Span<const uint8_t> src, Span<uint8_t> dest,
> -			   Span<const uint8_t> exifData, unsigned int quality)
> +int EncoderLibJpeg::encode(const std::vector<Span<uint8_t>> &src,
> +			   Span<uint8_t> dest, Span<const uint8_t> exifData,
> +			   unsigned int quality)
>  {
>  	unsigned char *destination = dest.data();
>  	unsigned long size = dest.size();
> diff --git a/src/android/jpeg/encoder_libjpeg.h b/src/android/jpeg/encoder_libjpeg.h
> index 61fbd1a69278..45ffbd7fae5d 100644
> --- a/src/android/jpeg/encoder_libjpeg.h
> +++ b/src/android/jpeg/encoder_libjpeg.h
> @@ -9,6 +9,8 @@
>  
>  #include "encoder.h"
>  
> +#include <vector>
> +
>  #include "libcamera/internal/formats.h"
>  
>  #include <jpeglib.h>
> @@ -24,14 +26,14 @@ public:
>  		   libcamera::Span<uint8_t> destination,
>  		   libcamera::Span<const uint8_t> exifData,
>  		   unsigned int quality) override;
> -	int encode(libcamera::Span<const uint8_t> source,
> +	int encode(const std::vector<libcamera::Span<uint8_t>> &planes,
>  		   libcamera::Span<uint8_t> destination,
>  		   libcamera::Span<const uint8_t> exifData,
>  		   unsigned int quality);
>  
>  private:
> -	void compressRGB(libcamera::Span<const uint8_t> frame);
> -	void compressNV(libcamera::Span<const uint8_t> frame);
> +	void compressRGB(const std::vector<libcamera::Span<uint8_t>> &planes);
> +	void compressNV(const std::vector<libcamera::Span<uint8_t>> &planes);
>  
>  	struct jpeg_compress_struct compress_;
>  	struct jpeg_error_mgr jerr_;
> diff --git a/src/android/jpeg/post_processor_jpeg.cpp b/src/android/jpeg/post_processor_jpeg.cpp
> index 3160a784419c..68d74842925d 100644
> --- a/src/android/jpeg/post_processor_jpeg.cpp
> +++ b/src/android/jpeg/post_processor_jpeg.cpp
> @@ -72,7 +72,7 @@ void PostProcessorJpeg::generateThumbnail(const FrameBuffer &source,
>  		 */
>  		thumbnail->resize(rawThumbnail.size());
>  
> -		int jpeg_size = thumbnailEncoder_.encode(rawThumbnail,
> +		int jpeg_size = thumbnailEncoder_.encode({ rawThumbnail },
>  							 *thumbnail, {}, quality);
>  		thumbnail->resize(jpeg_size);
>  
> diff --git a/src/android/jpeg/thumbnailer.cpp b/src/android/jpeg/thumbnailer.cpp
> index 043c7b33f06a..2c341535de9e 100644
> --- a/src/android/jpeg/thumbnailer.cpp
> +++ b/src/android/jpeg/thumbnailer.cpp
> @@ -62,8 +62,8 @@ void Thumbnailer::createThumbnail(const FrameBuffer &source,
>  	ASSERT(tw % 2 == 0 && th % 2 == 0);
>  

Possibly ASSERT(frame.planes().size() >= 2 here too.

But either way,

Reviewed-by: Kieran Bingham <kieran.bingham at ideasonboard.com>

>  	/* Image scaling block implementing nearest-neighbour algorithm. */
> -	unsigned char *src = static_cast<unsigned char *>(frame.planes()[0].data());
> -	unsigned char *srcC = src + sh * sw;
> +	unsigned char *src = frame.planes()[0].data();
> +	unsigned char *srcC = frame.planes()[1].data();
>  	unsigned char *srcCb, *srcCr;
>  	unsigned char *dstY, *srcY;
>  
>