[libcamera-devel] [PATCH 02/15] android: camera_stream: Add CameraStream::Type

Laurent Pinchart laurent.pinchart at ideasonboard.com
Mon Oct 5 12:46:36 CEST 2020


From: Jacopo Mondi <jacopo at jmondi.org>

Define the CameraStream::Type enumeration and assign it to
each CameraStream instance at construction time.

The CameraStream type will be used to decide if memory needs to be
allocated on its behalf or if the stream is backed by memory externally
allocated by the Android framework.

Reviewed-by: Laurent Pinchart <laurent.pinchart at ideasonboard.com>
Reviewed-by: Kieran Bingham <kieran.bingham at ideasonboard.com>
Reviewed-by: Hirokazu Honda <hiroh at chromium.org>
Reviewed-by: Niklas Söderlund <niklas.soderlund at ragnatech.se>
Signed-off-by: Jacopo Mondi <jacopo at jmondi.org>
---
 src/android/camera_device.cpp |  8 +++-
 src/android/camera_stream.cpp |  4 +-
 src/android/camera_stream.h   | 86 ++++++++++++++++++++++++++++++++++-
 3 files changed, 93 insertions(+), 5 deletions(-)

diff --git a/src/android/camera_device.cpp b/src/android/camera_device.cpp
index bbc692fe109f..0600ebc81c64 100644
--- a/src/android/camera_device.cpp
+++ b/src/android/camera_device.cpp
@@ -1216,12 +1216,14 @@ int CameraDevice::configureStreams(camera3_stream_configuration_t *stream_list)
 
 		config_->addConfiguration(streamConfiguration);
 		unsigned int index = config_->size() - 1;
-		streams_.emplace_back(format, size, index);
+		streams_.emplace_back(format, size, CameraStream::Type::Direct,
+				      index);
 		stream->priv = static_cast<void *>(&streams_.back());
 	}
 
 	/* Now handle the MJPEG streams, adding a new stream if required. */
 	if (jpegStream) {
+		CameraStream::Type type;
 		int index = -1;
 
 		/* Search for a compatible stream in the non-JPEG ones. */
@@ -1239,6 +1241,7 @@ int CameraDevice::configureStreams(camera3_stream_configuration_t *stream_list)
 			LOG(HAL, Info)
 				<< "Android JPEG stream mapped to libcamera stream " << i;
 
+			type = CameraStream::Type::Mapped;
 			index = i;
 			break;
 		}
@@ -1263,6 +1266,7 @@ int CameraDevice::configureStreams(camera3_stream_configuration_t *stream_list)
 			LOG(HAL, Info) << "Adding " << streamConfiguration.toString()
 				       << " for MJPEG support";
 
+			type = CameraStream::Type::Internal;
 			config_->addConfiguration(streamConfiguration);
 			index = config_->size() - 1;
 		}
@@ -1281,7 +1285,7 @@ int CameraDevice::configureStreams(camera3_stream_configuration_t *stream_list)
 			return ret;
 		}
 
-		streams_.emplace_back(formats::MJPEG, cfg.size, index, encoder);
+		streams_.emplace_back(formats::MJPEG, cfg.size, type, index, encoder);
 		jpegStream->priv = static_cast<void *>(&streams_.back());
 	}
 
diff --git a/src/android/camera_stream.cpp b/src/android/camera_stream.cpp
index 01c62978ca3a..585bf2b68f4f 100644
--- a/src/android/camera_stream.cpp
+++ b/src/android/camera_stream.cpp
@@ -10,7 +10,7 @@
 using namespace libcamera;
 
 CameraStream::CameraStream(PixelFormat format, Size size,
-			   unsigned int index, Encoder *encoder)
-	: format_(format), size_(size), index_(index), encoder_(encoder)
+			   Type type, unsigned int index, Encoder *encoder)
+	: format_(format), size_(size), type_(type), index_(index), encoder_(encoder)
 {
 }
diff --git a/src/android/camera_stream.h b/src/android/camera_stream.h
index 10dece7beb69..07c714e3a365 100644
--- a/src/android/camera_stream.h
+++ b/src/android/camera_stream.h
@@ -17,17 +17,101 @@
 class CameraStream
 {
 public:
+	/*
+	 * Enumeration of CameraStream types.
+	 *
+	 * A camera stream associates an Android stream to a libcamera stream.
+	 * This enumeration describes how the two streams are associated and how
+	 * and where data produced from libcamera are delivered to the
+	 * Android framework.
+	 *
+	 * Direct:
+	 *
+	 * The Android stream is directly mapped onto a libcamera stream: frames
+	 * are delivered by the library directly in the memory location
+	 * specified by the Android stream (buffer_handle_t->data) and provided
+	 * to the framework as they are. The Android stream characteristics are
+	 * directly translated to the libcamera stream configuration.
+	 *
+	 * +-----+                +-----+
+	 * |  A  |                |  L  |
+	 * +-----+                +-----+
+	 *    |                      |
+	 *    V                      V
+	 * +-----+                +------+
+	 * |  B  |<---------------|  FB  |
+	 * +-----+                +------+
+	 *
+	 *
+	 * Internal:
+	 *
+	 * Data for the Android stream is produced by processing a libcamera
+	 * stream created by the HAL for that purpose. The libcamera stream
+	 * needs to be supplied with intermediate buffers where the library
+	 * delivers frames to be processed and then provided to the framework.
+	 * The libcamera stream configuration is not a direct translation of the
+	 * Android stream characteristics, but it describes the format and size
+	 * required for the processing procedure to produce frames in the
+	 * Android required format.
+	 *
+	 * +-----+                +-----+
+	 * |  A  |                |  L  |
+	 * +-----+                +-----+
+	 *    |                      |
+	 *    V                      V
+	 * +-----+                +------+
+	 * |  B  |                |  FB  |
+	 * +-----+                +------+
+	 *   ^                       |
+	 *   |-------Processing------|
+	 *
+	 *
+	 * Mapped:
+	 *
+	 * Data for the Android stream is produced by processing a libcamera
+	 * stream associated with another CameraStream. Mapped camera streams do
+	 * not need any memory to be reserved for them as they process data
+	 * produced by libcamera for a different stream whose format and size
+	 * is compatible with the processing procedure requirements to produce
+	 * frames in the Android required format.
+	 *
+	 * +-----+      +-----+          +-----+
+	 * |  A  |      |  A' |          |  L  |
+	 * +-----+      +-----+          +-----+
+	 *    |            |                |
+	 *    V            V                V
+	 * +-----+      +-----+          +------+
+	 * |  B  |      |  B' |<---------|  FB  |
+	 * +-----+      +-----+          +------+
+	 *   ^              |
+	 *   |--Processing--|
+	 *
+	 *
+	 * --------------------------------------------------------------------
+	 * A  = Android stream
+	 * L  = libcamera stream
+	 * B  = memory buffer
+	 * FB = libcamera FrameBuffer
+	 * "Processing" = Frame processing procedure (Encoding, scaling etc)
+	 */
+	enum class Type {
+		Direct,
+		Internal,
+		Mapped,
+	};
 	CameraStream(libcamera::PixelFormat format, libcamera::Size size,
-		     unsigned int index, Encoder *encoder = nullptr);
+		     Type type, unsigned int index, Encoder *encoder = nullptr);
 
 	const libcamera::PixelFormat &format() const { return format_; }
 	const libcamera::Size &size() const { return size_; }
+	Type type() const { return type_; }
 	unsigned int index() const { return index_; }
 	Encoder *encoder() const { return encoder_.get(); }
 
 private:
 	libcamera::PixelFormat format_;
 	libcamera::Size size_;
+	Type type_;
 	/*
 	 * The index of the libcamera StreamConfiguration as added during
 	 * configureStreams(). A single libcamera Stream may be used to deliver
-- 
Regards,

Laurent Pinchart



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