[libcamera-devel] [PATCH v2 6/8] libcamera: v4l2_videodevice: Add multiplanar argument to toV4L2PixelFormat

[Jacopo Mondi]

The toV4L2PixelFormat() function selects which V4L2 format variant to
use (contiguous planes vs non-contiguous version) by using video device
multiplanar API from the capabilities.

The isMultiplanar() function however verifies if the video device uses
the singleplanar or the multiplanar V4L2 API, something which is
unrelated to the format variant to use.

Add a 'multiplanar' flag, which defaults to false, to the
toV4L2PixelFormat() function to allow explicit selection of the format
variant.

Signed-off-by: Jacopo Mondi <jacopo at jmondi.org>
---
 include/libcamera/internal/v4l2_videodevice.h |  3 ++-
 src/libcamera/v4l2_videodevice.cpp            | 13 +++++++------
 2 files changed, 9 insertions(+), 7 deletions(-)

diff --git a/include/libcamera/internal/v4l2_videodevice.h b/include/libcamera/internal/v4l2_videodevice.h
index 6d8850c99afd..64296c5849f2 100644
--- a/include/libcamera/internal/v4l2_videodevice.h
+++ b/include/libcamera/internal/v4l2_videodevice.h
@@ -228,7 +228,8 @@ public:
 	static std::unique_ptr<V4L2VideoDevice>
 	fromEntityName(const MediaDevice *media, const std::string &entity);
 
-	V4L2PixelFormat toV4L2PixelFormat(const PixelFormat &pixelFormat) const;
+	V4L2PixelFormat toV4L2PixelFormat(const PixelFormat &pixelFormat,
+					  bool multiplanar = false) const;
 
 protected:
 	std::string logPrefix() const override;
diff --git a/src/libcamera/v4l2_videodevice.cpp b/src/libcamera/v4l2_videodevice.cpp
index a3242ba755c0..767ab2361ef5 100644
--- a/src/libcamera/v4l2_videodevice.cpp
+++ b/src/libcamera/v4l2_videodevice.cpp
@@ -1992,23 +1992,24 @@ V4L2VideoDevice::fromEntityName(const MediaDevice *media,
 /**
  * \brief Convert \a PixelFormat to one of the device supported V4L2 FourCC
  * \param[in] pixelFormat The PixelFormat to convert
+ * \param[in] multiplanar Use the multiplanar format version, default to false
  *
  * Convert a\ pixelformat to a V4L2 FourCC that is known to be supported by
  * the video device.
  *
- * For multiplanar formats, the V4L2 format variant (contiguous or
- * non-contiguous planes) is selected automatically based on the capabilities
- * of the video device. If the video device supports the V4L2 multiplanar API,
- * non-contiguous formats are preferred.
+ * V4L2 defines different format variants for the same format when using
+ * contiguous or non-contiguous planes. The \a multiplanar parameter allows
+ * to select which variant to use.
  *
  * \return The V4L2PixelFormat corresponding to \a pixelFormat or an invalid
  * PixelFormat if \a pixelFormat is not supported by the video device
  */
-V4L2PixelFormat V4L2VideoDevice::toV4L2PixelFormat(const PixelFormat &pixelFormat) const
+V4L2PixelFormat V4L2VideoDevice::toV4L2PixelFormat(const PixelFormat &pixelFormat,
+						   bool multiplanar) const
 {
 	std::vector<V4L2PixelFormat> deviceFormats = enumPixelformats(0);
 	std::vector<V4L2PixelFormat> v4l2PixelFormats =
-		V4L2PixelFormat::fromPixelFormat(pixelFormat, caps_.isMultiplanar());
+		V4L2PixelFormat::fromPixelFormat(pixelFormat, multiplanar);
 
 	for (const V4L2PixelFormat &v4l2Format : v4l2PixelFormats) {
 		auto it = std::find_if(deviceFormats.begin(), deviceFormats.end(),
-- 
2.37.1