[libcamera-devel] [PATCH v2 01/17] libcamera: ipu3: Use the optimal sensor size

[Jacopo Mondi]

As reported by commit 7208e70211a6 ("libcamera: ipu3: Always use sensor
full frame size") the current implementation of the IPU3 pipeline
handler always uses the sensor resolution as the ImgU input frame size in
order to work around an issue with the ImgU configuration procedure.

Now that the frame selection policy has been modified in the CIO2Device
class implementation to comply with the requirements of the ImgU
configuration script we can remove the workaround and select the most
opportune sensor size to feed the ImgU with.

Signed-off-by: Jacopo Mondi <jacopo at jmondi.org>
Reviewed-by: Paul Elder <paul.elder at ideasonboard.com>
Reviewed-by: Umang Jain <umang.jain at ideasonboard.com>
---
 src/libcamera/pipeline/ipu3/ipu3.cpp | 41 ++++++++++++++++------------
 1 file changed, 23 insertions(+), 18 deletions(-)

diff --git a/src/libcamera/pipeline/ipu3/ipu3.cpp b/src/libcamera/pipeline/ipu3/ipu3.cpp
index c287bf86e79a..291338288685 100644
--- a/src/libcamera/pipeline/ipu3/ipu3.cpp
+++ b/src/libcamera/pipeline/ipu3/ipu3.cpp
@@ -229,7 +229,16 @@ CameraConfiguration::Status IPU3CameraConfiguration::validate()
 		status = Adjusted;
 	}
 
-	/* Validate the requested stream configuration */
+	/*
+	 * Validate the requested stream configuration and select the sensor
+	 * format by collecting the maximum RAW stream width and height and
+	 * picking the closest larger match.
+	 *
+	 * If no RAW stream is requested use the one of the largest YUV stream,
+	 * plus margin pixels for the IF and BDS rectangle to downscale.
+	 *
+	 * \todo Clarify the IF and BDS margins requirements.
+	 */
 	unsigned int rawCount = 0;
 	unsigned int yuvCount = 0;
 	Size maxYuvSize;
@@ -240,7 +249,7 @@ CameraConfiguration::Status IPU3CameraConfiguration::validate()
 
 		if (info.colourEncoding == PixelFormatInfo::ColourEncodingRAW) {
 			rawCount++;
-			rawSize = cfg.size;
+			rawSize.expandTo(cfg.size);
 		} else {
 			yuvCount++;
 			maxYuvSize.expandTo(cfg.size);
@@ -269,24 +278,20 @@ CameraConfiguration::Status IPU3CameraConfiguration::validate()
 	/*
 	 * Generate raw configuration from CIO2.
 	 *
-	 * \todo The image sensor frame size should be selected to optimize
-	 * operations based on the sizes of the requested streams. However such
-	 * a selection makes the pipeline configuration procedure fail for small
-	 * resolutions (for example: 640x480 with OV5670) and causes the capture
-	 * operations to stall for some stream size combinations (see the
-	 * commit message of the patch that introduced this comment for more
-	 * failure examples).
+	 * The output YUV streams will be limited in size to the
+	 * maximum frame size requested for the RAW stream, if present.
 	 *
-	 * Until the sensor frame size calculation criteria are clarified, when
-	 * capturing from ImgU always use the largest possible size which
-	 * guarantees better results at the expense of the frame rate and CSI-2
-	 * bus bandwidth. When only a raw stream is requested use the requested
-	 * size instead, as the ImgU is not involved.
+	 * If no raw stream is requested generate a size as large as the maximum
+	 * requested YUV size aligned to the ImgU constraints and bound by the
+	 * sensor's maximum resolution. See
+	 * https://bugs.libcamera.org/show_bug.cgi?id=32
 	 */
-	if (!yuvCount)
-		cio2Configuration_ = data_->cio2_.generateConfiguration(rawSize);
-	else
-		cio2Configuration_ = data_->cio2_.generateConfiguration({});
+	if (rawSize.isNull())
+		rawSize = maxYuvSize.alignedUpTo(40, 540)
+				    .alignedUpTo(IMGU_OUTPUT_WIDTH_MARGIN,
+						 IMGU_OUTPUT_HEIGHT_MARGIN)
+				    .boundedTo(data_->cio2_.sensor()->resolution());
+	cio2Configuration_ = data_->cio2_.generateConfiguration(rawSize);
 	if (!cio2Configuration_.pixelFormat.isValid())
 		return Invalid;
 
-- 
2.32.0