[libcamera-devel] [PATCH v3 6/8] android: jpeg: Configure thumbnailer based on request metadata

[Paul Elder]

Configure the thumbnailer based on the thumbnail parameters given by the
android request metadata. Only the thumbnail encoder needs to be
configured, and since it is only used at post-processing time, move the
configuration out of the post-processor constructor and into the
processing step.

Also set the following android result metadata tags:
- ANDROID_JPEG_THUMBNAIL_SIZE
- ANDROID_JPEG_THUMBNAIL_QUALITY

Signed-off-by: Paul Elder <paul.elder at ideasonboard.com>

---
New in v3
- split from "android: Set result metadata and EXIF fields based on
  request"
---
 src/android/jpeg/post_processor_jpeg.cpp | 40 +++++++++++++++++-------
 src/android/jpeg/post_processor_jpeg.h   |  1 +
 src/android/jpeg/thumbnailer.cpp         | 25 ++-------------
 src/android/jpeg/thumbnailer.h           |  4 +--
 4 files changed, 34 insertions(+), 36 deletions(-)

diff --git a/src/android/jpeg/post_processor_jpeg.cpp b/src/android/jpeg/post_processor_jpeg.cpp
index b325a06a..e5e42d39 100644
--- a/src/android/jpeg/post_processor_jpeg.cpp
+++ b/src/android/jpeg/post_processor_jpeg.cpp
@@ -41,12 +41,6 @@ int PostProcessorJpeg::configure(const StreamConfiguration &inCfg,
 	streamSize_ = outCfg.size;
 
 	thumbnailer_.configure(inCfg.size, inCfg.pixelFormat);
-	StreamConfiguration thCfg = inCfg;
-	thCfg.size = thumbnailer_.size();
-	if (thumbnailEncoder_.configure(thCfg) != 0) {
-		LOG(JPEG, Error) << "Failed to configure thumbnail encoder";
-		return -EINVAL;
-	}
 
 	encoder_ = std::make_unique<EncoderLibJpeg>();
 
@@ -54,14 +48,20 @@ int PostProcessorJpeg::configure(const StreamConfiguration &inCfg,
 }
 
 void PostProcessorJpeg::generateThumbnail(const FrameBuffer &source,
+					  const Size &targetSize,
 					  std::vector<unsigned char> *thumbnail)
 {
 	/* Stores the raw scaled-down thumbnail bytes. */
 	std::vector<unsigned char> rawThumbnail;
 
-	thumbnailer_.createThumbnail(source, &rawThumbnail);
+	thumbnailer_.createThumbnail(source, targetSize, &rawThumbnail);
+
+	StreamConfiguration thCfg;
+	thCfg.size = targetSize;
+	thCfg.pixelFormat = thumbnailer_.pixelFormat();
+	int ret = thumbnailEncoder_.configure(thCfg);
 
-	if (!rawThumbnail.empty()) {
+	if (!rawThumbnail.empty() && !ret) {
 		/*
 		 * \todo Avoid value-initialization of all elements of the
 		 * vector.
@@ -125,10 +125,26 @@ int PostProcessorJpeg::process(const FrameBuffer &source,
 					 entry.data.i64, 1);
 	}
 
-	std::vector<unsigned char> thumbnail;
-	generateThumbnail(source, &thumbnail);
-	if (!thumbnail.empty())
-		exif.setThumbnail(thumbnail, Exif::Compression::JPEG);
+	ret = requestMetadata.getEntry(ANDROID_JPEG_THUMBNAIL_SIZE, &entry);
+	if (ret) {
+		const int32_t *data = entry.data.i32;
+		Size thumbnailSize = { static_cast<uint32_t>(data[0]),
+				       static_cast<uint32_t>(data[1]) };
+
+		if (thumbnailSize != Size(0, 0)) {
+			std::vector<unsigned char> thumbnail;
+			generateThumbnail(source, thumbnailSize, &thumbnail);
+			if (!thumbnail.empty())
+				exif.setThumbnail(thumbnail, Exif::Compression::JPEG);
+		}
+
+		resultMetadata->addEntry(ANDROID_JPEG_THUMBNAIL_SIZE, data, 2);
+
+		/* \todo Use this quality as a parameter to the encoder */
+		ret = requestMetadata.getEntry(ANDROID_JPEG_THUMBNAIL_QUALITY, &entry);
+		if (ret)
+			resultMetadata->addEntry(ANDROID_JPEG_THUMBNAIL_QUALITY, entry.data.u8, 1);
+	}
 
 	ret = requestMetadata.getEntry(ANDROID_JPEG_GPS_COORDINATES, &entry);
 	if (ret) {
diff --git a/src/android/jpeg/post_processor_jpeg.h b/src/android/jpeg/post_processor_jpeg.h
index d721d1b9..660b79b4 100644
--- a/src/android/jpeg/post_processor_jpeg.h
+++ b/src/android/jpeg/post_processor_jpeg.h
@@ -31,6 +31,7 @@ public:
 
 private:
 	void generateThumbnail(const libcamera::FrameBuffer &source,
+			       const libcamera::Size &targetSize,
 			       std::vector<unsigned char> *thumbnail);
 
 	CameraDevice *const cameraDevice_;
diff --git a/src/android/jpeg/thumbnailer.cpp b/src/android/jpeg/thumbnailer.cpp
index 5374538a..f709d343 100644
--- a/src/android/jpeg/thumbnailer.cpp
+++ b/src/android/jpeg/thumbnailer.cpp
@@ -32,30 +32,11 @@ void Thumbnailer::configure(const Size &sourceSize, PixelFormat pixelFormat)
 		return;
 	}
 
-	targetSize_ = computeThumbnailSize();
-
 	valid_ = true;
 }
 
-/*
- * The Exif specification recommends the width of the thumbnail to be a
- * multiple of 16 (section 4.8.1). Hence, compute the corresponding height
- * keeping the aspect ratio same as of the source.
- */
-Size Thumbnailer::computeThumbnailSize() const
-{
-	unsigned int targetHeight;
-	constexpr unsigned int kTargetWidth = 160;
-
-	targetHeight = kTargetWidth * sourceSize_.height / sourceSize_.width;
-
-	if (targetHeight & 1)
-		targetHeight++;
-
-	return Size(kTargetWidth, targetHeight);
-}
-
 void Thumbnailer::createThumbnail(const FrameBuffer &source,
+				  const Size &targetSize,
 				  std::vector<unsigned char> *destination)
 {
 	MappedFrameBuffer frame(&source, PROT_READ);
@@ -73,8 +54,8 @@ void Thumbnailer::createThumbnail(const FrameBuffer &source,
 
 	const unsigned int sw = sourceSize_.width;
 	const unsigned int sh = sourceSize_.height;
-	const unsigned int tw = targetSize_.width;
-	const unsigned int th = targetSize_.height;
+	const unsigned int tw = targetSize.width;
+	const unsigned int th = targetSize.height;
 
 	ASSERT(tw % 2 == 0 && th % 2 == 0);
 
diff --git a/src/android/jpeg/thumbnailer.h b/src/android/jpeg/thumbnailer.h
index 98f11833..bbd9832d 100644
--- a/src/android/jpeg/thumbnailer.h
+++ b/src/android/jpeg/thumbnailer.h
@@ -20,15 +20,15 @@ public:
 	void configure(const libcamera::Size &sourceSize,
 		       libcamera::PixelFormat pixelFormat);
 	void createThumbnail(const libcamera::FrameBuffer &source,
+			     const libcamera::Size &targetSize,
 			     std::vector<unsigned char> *dest);
-	const libcamera::Size &size() const { return targetSize_; }
+	const libcamera::PixelFormat &pixelFormat() const { return pixelFormat_; }
 
 private:
 	libcamera::Size computeThumbnailSize() const;
 
 	libcamera::PixelFormat pixelFormat_;
 	libcamera::Size sourceSize_;
-	libcamera::Size targetSize_;
 
 	bool valid_;
 };
-- 
2.27.0