android: jpeg: Port to PostProcessor interface

Port the CameraStream's JPEG-encoding bits to PostProcessorJpeg.
This encapsulates the encoder and EXIF generation code into the
PostProcessorJpeg layer and removes these specifics related to JPEG,
from the CameraStream itself.

Signed-off-by: Umang Jain <email@uajain.com>
Tested-by: Kieran Bingham <kieran.bingham@ideasonboard.com>
Reviewed-by: Kieran Bingham <kieran.bingham@ideasonboard.com>
Reviewed-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Signed-off-by: Kieran Bingham <kieran.bingham@ideasonboard.com>
Change-Id: Id9e6e9b2bec83493a90e5e126298a2bb2ed2232a

src/android/jpeg/post_processor_jpeg.cpp

@@ -0,0 +1,105 @@
+/* SPDX-License-Identifier: GPL-2.0-or-later */
+/*
+ * Copyright (C) 2020, Google Inc.
+ *
+ * post_processor_jpeg.cpp - JPEG Post Processor
+ */
+
+#include "post_processor_jpeg.h"
+
+#include "../camera_device.h"
+#include "../camera_metadata.h"
+#include "encoder_libjpeg.h"
+#include "exif.h"
+
+#include <libcamera/formats.h>
+
+#include "libcamera/internal/log.h"
+
+using namespace libcamera;
+
+LOG_DEFINE_CATEGORY(JPEG);
+
+PostProcessorJpeg::PostProcessorJpeg(CameraDevice *device)
+	: cameraDevice_(device)
+{
+}
+
+int PostProcessorJpeg::configure(const StreamConfiguration &inCfg,
+				 const StreamConfiguration &outCfg)
+{
+	if (inCfg.size != outCfg.size) {
+		LOG(JPEG, Error) << "Mismatch of input and output stream sizes";
+		return -EINVAL;
+	}
+
+	if (outCfg.pixelFormat != formats::MJPEG) {
+		LOG(JPEG, Error) << "Output stream pixel format is not JPEG";
+		return -EINVAL;
+	}
+
+	streamSize_ = outCfg.size;
+	encoder_ = std::make_unique<EncoderLibJpeg>();
+
+	return encoder_->configure(inCfg);
+}
+
+int PostProcessorJpeg::process(const libcamera::FrameBuffer *source,
+			       const libcamera::Span<uint8_t> &destination,
+			       CameraMetadata *metadata)
+{
+	if (!encoder_)
+		return 0;
+
+	/* Set EXIF metadata for various tags. */
+	Exif exif;
+	/* \todo Set Make and Model from external vendor tags. */
+	exif.setMake("libcamera");
+	exif.setModel("cameraModel");
+	exif.setOrientation(cameraDevice_->orientation());
+	exif.setSize(streamSize_);
+	/*
+	 * We set the frame's EXIF timestamp as the time of encode.
+	 * Since the precision we need for EXIF timestamp is only one
+	 * second, it is good enough.
+	 */
+	exif.setTimestamp(std::time(nullptr));
+	if (exif.generate() != 0)
+		LOG(JPEG, Error) << "Failed to generate valid EXIF data";
+
+	int jpeg_size = encoder_->encode(source, destination, exif.data());
+	if (jpeg_size < 0) {
+		LOG(JPEG, Error) << "Failed to encode stream image";
+		return jpeg_size;
+	}
+
+	/*
+	 * Fill in the JPEG blob header.
+	 *
+	 * The mapped size of the buffer is being returned as
+	 * substantially larger than the requested JPEG_MAX_SIZE
+	 * (which is referenced from maxJpegBufferSize_). Utilise
+	 * this static size to ensure the correct offset of the blob is
+	 * determined.
+	 *
+	 * \todo Investigate if the buffer size mismatch is an issue or
+	 * expected behaviour.
+	 */
+	uint8_t *resultPtr = destination.data() +
+			     cameraDevice_->maxJpegBufferSize() -
+			     sizeof(struct camera3_jpeg_blob);
+	auto *blob = reinterpret_cast<struct camera3_jpeg_blob *>(resultPtr);
+	blob->jpeg_blob_id = CAMERA3_JPEG_BLOB_ID;
+	blob->jpeg_size = jpeg_size;
+
+	/* Update the JPEG result Metadata. */
+	metadata->addEntry(ANDROID_JPEG_SIZE, &jpeg_size, 1);
+
+	const uint32_t jpeg_quality = 95;
+	metadata->addEntry(ANDROID_JPEG_QUALITY, &jpeg_quality, 1);
+
+	const uint32_t jpeg_orientation = 0;
+	metadata->addEntry(ANDROID_JPEG_ORIENTATION, &jpeg_orientation, 1);
+
+	return 0;
+}