[libcamera-devel] [PATCH v5 1/3] android: camera_metadata: Auto-resize CameraMetadata

Paul Elder paul.elder at ideasonboard.com
Fri May 14 08:43:01 CEST 2021


Previously we had to manually declare the size of CameraMetadata on
allocation, and its count could not be changed after construction.
Change CameraMetadata's behavior so that the user can simply add or
update entries, and the CameraMetadata will auto-resize (double the
size) as necessary. Also remove everything involved with calculating
the initial size for any CameraMetadata instances.

Signed-off-by: Paul Elder <paul.elder at ideasonboard.com>
Reviewed-by: Niklas Söderlund <niklas.soderlund at ragnatech.se>

---
Changes in v5:
- add overload for C arrays

Changes in v4:
- upgrade the second overload to allow STL containers instead of just
  vector
  - the main use case I'm imagining is vector and array. C arrays won't
    work because they don't have .data() and .size() (the latter is the
    more important one)
  - libcamera::Span doesn't work because the template engine can't match
    std::vector/std::array to libcamera::Span
    - ‘std::vector<int>’ is not derived from ‘libcamera::Span<const T>’
- return bool from addEntry and updateEntry

Changes in v3:
- dependency on "FULL hardware level fixes" removed
- split addEntry and updateEntry
  - i think the lookup on every (merged) addEntry isn't worth it, since
    the user probably knows if they need to add or update
- add auto-resize (and corresponding check) to updateEntry as well
- add the templates and overloads to updateEntry as well
- increase the default size for the static metadata to be above what we
  had before
- valid_ is now used to indicate a failed addEntry/updateEntry in
  addition to metadata_ == nullptr. this way the user doesn't have to
  check the return value of every single addEntry/updateEntry call, and
  can just check valid_ at the end
- print resize when it happens
- updateEntry resizes if the new data size is greater than the old data

Question: I think on failure of addEntry/updateEntry the metadata could
still be "valid", it's just that the content isn't what the user
expects. Should we keep valid_ as I've repurposed it here in v3, or
should we add another flag?

Changes in v2:
- add overloading of addEntry
- better logging with the separation of core code vs template code
- addEntry failure makes the metadata invalid

The main feature of v2 is the overloading of addEntry. I have three
overloads and the main one:
- tag, single piece of data (reference)
- tag, C array (v5)
- tag, STL container (v3: s/span/vector/) (v4: s/vector/STL container/)
- tag, data pointer, count
- tag, data pointer, count, size of one instance of the data

The last one is the main one, and is not templated. The first two are
nice and convenient, because now we can do things like:

uint32_t orientation = 0;
resultMetadata->addEntry(ANDROID_JPEG_ORIENTATION, orientation);

and

std::vector<uint32_t> availableStates = { SOME_STATE_1, SOME_STATE_2 };
metadata->addEntry(ANDROID_AVAILABLE_STATES, availableStates);

The third is for when android metadata is copied directly from another
piece of android metadata. All the old calls are backward-compatible
using this overload.
---
 src/android/camera_device.cpp   | 47 +-----------------
 src/android/camera_device.h     |  1 -
 src/android/camera_metadata.cpp | 84 +++++++++++++++++++++++++++++----
 src/android/camera_metadata.h   | 52 +++++++++++++++++++-
 4 files changed, 127 insertions(+), 57 deletions(-)

diff --git a/src/android/camera_device.cpp b/src/android/camera_device.cpp
index 7d4d0feb..74f6915c 100644
--- a/src/android/camera_device.cpp
+++ b/src/android/camera_device.cpp
@@ -773,43 +773,6 @@ void CameraDevice::setCallbacks(const camera3_callback_ops_t *callbacks)
 	callbacks_ = callbacks;
 }
 
-std::tuple<uint32_t, uint32_t> CameraDevice::calculateStaticMetadataSize()
-{
-	/*
-	 * \todo Keep this in sync with the actual number of entries.
-	 * Currently: 54 entries, 874 bytes of static metadata
-	 */
-	uint32_t numEntries = 54;
-	uint32_t byteSize = 874;
-
-	/*
-	 * Calculate space occupation in bytes for dynamically built metadata
-	 * entries.
-	 *
-	 * Each stream configuration entry requires 48 bytes:
-	 * 4 32bits integers for ANDROID_SCALER_AVAILABLE_STREAM_CONFIGURATIONS
-	 * 4 64bits integers for ANDROID_SCALER_AVAILABLE_MIN_FRAME_DURATIONS
-	 */
-	byteSize += streamConfigurations_.size() * 48;
-
-	/*
-	 * 2 32bits integers for each HAL_PIXEL_FORMAT_BLOB for thumbnail sizes
-	 * 2 32bits integers for the (0, 0) thumbnail size
-	 *
-	 * This is a worst case estimates as different configurations with the
-	 * same aspect ratio will generate the same size.
-	 */
-	for (const auto &entry : streamConfigurations_) {
-		if (entry.androidFormat != HAL_PIXEL_FORMAT_BLOB)
-			continue;
-
-		byteSize += 8;
-	}
-	byteSize += 8;
-
-	return std::make_tuple(numEntries, byteSize);
-}
-
 /*
  * Return static information for the camera.
  */
@@ -818,15 +781,7 @@ const camera_metadata_t *CameraDevice::getStaticMetadata()
 	if (staticMetadata_)
 		return staticMetadata_->get();
 
-	/*
-	 * The here reported metadata are enough to implement a basic capture
-	 * example application, but a real camera implementation will require
-	 * more.
-	 */
-	uint32_t numEntries;
-	uint32_t byteSize;
-	std::tie(numEntries, byteSize) = calculateStaticMetadataSize();
-	staticMetadata_ = std::make_unique<CameraMetadata>(numEntries, byteSize);
+	staticMetadata_ = std::make_unique<CameraMetadata>(64, 1024);
 	if (!staticMetadata_->isValid()) {
 		LOG(HAL, Error) << "Failed to allocate static metadata";
 		staticMetadata_.reset();
diff --git a/src/android/camera_device.h b/src/android/camera_device.h
index 23457e47..ae162a45 100644
--- a/src/android/camera_device.h
+++ b/src/android/camera_device.h
@@ -98,7 +98,6 @@ private:
 	std::vector<libcamera::Size>
 	getRawResolutions(const libcamera::PixelFormat &pixelFormat);
 
-	std::tuple<uint32_t, uint32_t> calculateStaticMetadataSize();
 	libcamera::FrameBuffer *createFrameBuffer(const buffer_handle_t camera3buffer);
 	void notifyShutter(uint32_t frameNumber, uint64_t timestamp);
 	void notifyError(uint32_t frameNumber, camera3_stream_t *stream);
diff --git a/src/android/camera_metadata.cpp b/src/android/camera_metadata.cpp
index 6f1bcdbe..bf8d2781 100644
--- a/src/android/camera_metadata.cpp
+++ b/src/android/camera_metadata.cpp
@@ -63,11 +63,64 @@ bool CameraMetadata::getEntry(uint32_t tag, camera_metadata_ro_entry_t *entry) c
 	return true;
 }
 
-bool CameraMetadata::addEntry(uint32_t tag, const void *data, size_t count)
+/*
+ * \brief Resize the metadata container, if necessary
+ * \param[in] count Number of entries to add to the container
+ * \param[in] size Total size of entries to add, in bytes
+ * \return True if resize was successful or unnecessary, false otherwise
+ */
+bool CameraMetadata::resize(size_t count, size_t size)
+{
+	if (!valid_)
+		return false;
+
+	if (!count && !size)
+		return true;
+
+	size_t currentEntryCount = get_camera_metadata_entry_count(metadata_);
+	size_t currentEntryCapacity = get_camera_metadata_entry_capacity(metadata_);
+	size_t newEntryCapacity = currentEntryCapacity < currentEntryCount + count ?
+				  currentEntryCapacity * 2 : currentEntryCapacity;
+
+	size_t currentDataCount = get_camera_metadata_data_count(metadata_);
+	size_t currentDataCapacity = get_camera_metadata_data_capacity(metadata_);
+	size_t newDataCapacity = currentDataCapacity < currentDataCount + size ?
+				 currentDataCapacity * 2 : currentDataCapacity;
+
+	if (newEntryCapacity > currentEntryCapacity ||
+	    newDataCapacity > currentDataCapacity) {
+		camera_metadata_t *oldMetadata = metadata_;
+		metadata_ = allocate_camera_metadata(newEntryCapacity, newDataCapacity);
+		if (!metadata_) {
+			metadata_ = oldMetadata;
+			return false;
+		}
+
+		LOG(CameraMetadata, Info)
+			<< "Resized: old entry capacity " << currentEntryCapacity
+			<< ", old data capacity " << currentDataCapacity
+			<< ", new entry capacity " << newEntryCapacity
+			<< ", new data capacity " << newDataCapacity;
+
+		append_camera_metadata(metadata_, oldMetadata);
+		free_camera_metadata(oldMetadata);
+	}
+
+	return true;
+}
+
+bool CameraMetadata::addEntry(uint32_t tag, const void *data, size_t count,
+			      size_t sizeofT)
 {
 	if (!valid_)
 		return false;
 
+	if (!resize(1, count * sizeofT)) {
+		LOG(CameraMetadata, Error) << "Failed to resize";
+		valid_ = false;
+		return false;
+	}
+
 	if (!add_camera_metadata_entry(metadata_, tag, data, count))
 		return true;
 
@@ -99,16 +152,31 @@ bool CameraMetadata::updateEntry(uint32_t tag, const void *data, size_t count)
 		return false;
 	}
 
-	ret = update_camera_metadata_entry(metadata_, entry.index, data,
-					   count, nullptr);
-	if (ret) {
-		const char *name = get_camera_metadata_tag_name(tag);
-		LOG(CameraMetadata, Error)
-			<< "Failed to update tag " << (name ? name : "<unknown>");
+	size_t oldSize =
+		calculate_camera_metadata_entry_data_size(entry.type,
+							  entry.count);
+	size_t newSize =
+		calculate_camera_metadata_entry_data_size(entry.type,
+							  count);
+	size_t sizeIncrement = newSize - oldSize > 0 ? newSize - oldSize : 0;
+	if (!resize(0, sizeIncrement)) {
+		LOG(CameraMetadata, Error) << "Failed to resize";
+		valid_ = false;
 		return false;
 	}
 
-	return true;
+	ret = update_camera_metadata_entry(metadata_, entry.index, data,
+					   count, nullptr);
+	if (!ret)
+		return true;
+
+	const char *name = get_camera_metadata_tag_name(tag);
+	LOG(CameraMetadata, Error)
+		<< "Failed to update tag " << (name ? name : "<unknown>");
+
+	valid_ = false;
+
+	return false;
 }
 
 camera_metadata_t *CameraMetadata::get()
diff --git a/src/android/camera_metadata.h b/src/android/camera_metadata.h
index d653e2f0..07afd4b2 100644
--- a/src/android/camera_metadata.h
+++ b/src/android/camera_metadata.h
@@ -8,6 +8,7 @@
 #define __ANDROID_CAMERA_METADATA_H__
 
 #include <stdint.h>
+#include <vector>
 
 #include <system/camera_metadata.h>
 
@@ -23,9 +24,56 @@ public:
 	CameraMetadata &operator=(const CameraMetadata &other);
 
 	bool isValid() const { return valid_; }
+	bool resize(size_t count, size_t size);
 	bool getEntry(uint32_t tag, camera_metadata_ro_entry_t *entry) const;
-	bool addEntry(uint32_t tag, const void *data, size_t data_count);
-	bool updateEntry(uint32_t tag, const void *data, size_t data_count);
+
+	template<typename T,
+		 std::enable_if_t<std::is_arithmetic_v<T>> * = nullptr>
+	bool addEntry(uint32_t tag, const T &data)
+	{
+		return addEntry(tag, &data, 1, sizeof(T));
+	}
+
+	template<typename T, size_t size>
+	bool addEntry(uint32_t tag, const T (&data)[size])
+	{
+		return addEntry(tag, data, size, sizeof(T));
+	}
+
+	template<typename S,
+		 typename T = typename S::value_type>
+	bool addEntry(uint32_t tag, S &data)
+	{
+		return addEntry(tag, data.data(), data.size(), sizeof(T));
+	}
+
+	template<typename T>
+	bool addEntry(uint32_t tag, const T *data, size_t count)
+	{
+		return addEntry(tag, data, count, sizeof(T));
+	}
+
+	template<typename T>
+	bool updateEntry(uint32_t tag, const T &data)
+	{
+		return updateEntry(tag, &data, 1);
+	}
+
+	template<typename T, size_t size>
+	bool updateEntry(uint32_t tag, const T (&data)[size])
+	{
+		return updateEntry(tag, data, size, sizeof(T));
+	}
+
+	template<typename S,
+		 typename T = typename S::value_type>
+	bool updateEntry(uint32_t tag, S &data)
+	{
+		return updateEntry(tag, data.data(), data.size());
+	}
+
+	bool addEntry(uint32_t tag, const void *data, size_t count, size_t sizeofT);
+	bool updateEntry(uint32_t tag, const void *data, size_t count);
 
 	camera_metadata_t *get();
 	const camera_metadata_t *get() const;
-- 
2.27.0



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