libcamera: v4l2_pixelformat: Return a format list in fromPixelFormat()

As we prepare to associate multiple V4L2 FourCC to a single libcamera
format, make the V4L2PixelFormat::fromPixelFormat() return a list of
formats and convert all its users to pick the first one.

This change prepares to re-introduce V4L2VideoDevice::toV4L2PixelFormat()
which will instead match the list of V4L2 FourCC against the formats
supported by the video device.

While at it, reword the V4L2PixelFormat::fromPixelFormat() documentation
to distinguish between planar/multiplanar and contiguous/non-contiguous.

Signed-off-by: Jacopo Mondi <jacopo@jmondi.org>

12 files changed, 42 insertions, 40 deletions

diff --git a/include/libcamera/internal/v4l2_pixelformat.h b/include/libcamera/internal/v4l2_pixelformat.h
index fb2d5d0b..750f31fc 100644
--- a/include/libcamera/internal/v4l2_pixelformat.h
+++ b/include/libcamera/internal/v4l2_pixelformat.h
@@ -11,6 +11,7 @@
 #include <ostream>
 #include <stdint.h>
 #include <string>
+#include <vector>
 
 #include <linux/videodev2.h>
 
@@ -44,8 +45,9 @@ public:
 	const char *description() const;
 
 	PixelFormat toPixelFormat() const;
-	static V4L2PixelFormat fromPixelFormat(const PixelFormat &pixelFormat,
-					       bool multiplanar = false);
+	static std::vector<V4L2PixelFormat>
+		fromPixelFormat(const PixelFormat &pixelFormat,
+				bool multiplanar = false);
 
 private:
 	uint32_t fourcc_;
diff --git a/src/libcamera/pipeline/ipu3/cio2.cpp b/src/libcamera/pipeline/ipu3/cio2.cpp
index 08e254f7..4a13d169 100644
--- a/src/libcamera/pipeline/ipu3/cio2.cpp
+++ b/src/libcamera/pipeline/ipu3/cio2.cpp
@@ -203,7 +203,7 @@ int CIO2Device::configure(const Size &size, V4L2DeviceFormat *outputFormat)
 	if (itInfo == mbusCodesToPixelFormat.end())
 		return -EINVAL;
 
-	outputFormat->fourcc = V4L2PixelFormat::fromPixelFormat(itInfo->second);
+	outputFormat->fourcc = V4L2PixelFormat::fromPixelFormat(itInfo->second)[0];
 	outputFormat->size = sensorFormat.size;
 	outputFormat->planesCount = 1;
 
diff --git a/src/libcamera/pipeline/ipu3/imgu.cpp b/src/libcamera/pipeline/ipu3/imgu.cpp
index 59305f85..25116400 100644
--- a/src/libcamera/pipeline/ipu3/imgu.cpp
+++ b/src/libcamera/pipeline/ipu3/imgu.cpp
@@ -558,7 +558,7 @@ int ImgUDevice::configureVideoDevice(V4L2VideoDevice *dev, unsigned int pad,
 		return 0;
 
 	*outputFormat = {};
-	outputFormat->fourcc = V4L2PixelFormat::fromPixelFormat(formats::NV12);
+	outputFormat->fourcc = V4L2PixelFormat::fromPixelFormat(formats::NV12)[0];
 	outputFormat->size = cfg.size;
 	outputFormat->planesCount = 2;
 
diff --git a/src/libcamera/pipeline/raspberrypi/raspberrypi.cpp b/src/libcamera/pipeline/raspberrypi/raspberrypi.cpp
index 9d561415..6e813bcb 100644
--- a/src/libcamera/pipeline/raspberrypi/raspberrypi.cpp
+++ b/src/libcamera/pipeline/raspberrypi/raspberrypi.cpp
@@ -96,7 +96,7 @@ V4L2DeviceFormat toV4L2DeviceFormat(const V4L2SubdeviceFormat &format,
 	const PixelFormat pix = mbusCodeToPixelFormat(format.mbus_code, packingReq);
 	V4L2DeviceFormat deviceFormat;
 
-	deviceFormat.fourcc = V4L2PixelFormat::fromPixelFormat(pix);
+	deviceFormat.fourcc = V4L2PixelFormat::fromPixelFormat(pix)[0];
 	deviceFormat.size = format.size;
 	deviceFormat.colorSpace = format.colorSpace;
 	return deviceFormat;
@@ -516,14 +516,14 @@ CameraConfiguration::Status RPiCameraConfiguration::validate()
 
 		V4L2VideoDevice::Formats fmts = dev->formats();
 
-		if (fmts.find(V4L2PixelFormat::fromPixelFormat(cfgPixFmt)) == fmts.end()) {
+		if (fmts.find(V4L2PixelFormat::fromPixelFormat(cfgPixFmt)[0]) == fmts.end()) {
 			/* If we cannot find a native format, use a default one. */
 			cfgPixFmt = formats::NV12;
 			status = Adjusted;
 		}
 
 		V4L2DeviceFormat format;
-		format.fourcc = V4L2PixelFormat::fromPixelFormat(cfgPixFmt);
+		format.fourcc = V4L2PixelFormat::fromPixelFormat(cfgPixFmt)[0];
 		format.size = cfg.size;
 		format.colorSpace = cfg.colorSpace;
 
@@ -783,7 +783,7 @@ int PipelineHandlerRPi::configure(Camera *camera, CameraConfiguration *config)
 		RPi::Stream *stream = i == maxIndex ? &data->isp_[Isp::Output0]
 						    : &data->isp_[Isp::Output1];
 
-		V4L2PixelFormat fourcc = V4L2PixelFormat::fromPixelFormat(cfg.pixelFormat);
+		V4L2PixelFormat fourcc = V4L2PixelFormat::fromPixelFormat(cfg.pixelFormat)[0];
 		format.size = cfg.size;
 		format.fourcc = fourcc;
 		format.colorSpace = cfg.colorSpace;
@@ -829,7 +829,7 @@ int PipelineHandlerRPi::configure(Camera *camera, CameraConfiguration *config)
 		maxSize = Size(320, 240);
 		format = {};
 		format.size = maxSize;
-		format.fourcc = V4L2PixelFormat::fromPixelFormat(formats::YUV420);
+		format.fourcc = V4L2PixelFormat::fromPixelFormat(formats::YUV420)[0];
 		/* No one asked for output, so the color space doesn't matter. */
 		format.colorSpace = ColorSpace::Jpeg;
 		ret = data->isp_[Isp::Output0].dev()->setFormat(&format);
@@ -862,7 +862,7 @@ int PipelineHandlerRPi::configure(Camera *camera, CameraConfiguration *config)
 
 		output1Format.size = (format.size / 2).boundedTo(limit).alignedDownTo(2, 2);
 		output1Format.colorSpace = format.colorSpace;
-		output1Format.fourcc = V4L2PixelFormat::fromPixelFormat(formats::YUV420);
+		output1Format.fourcc = V4L2PixelFormat::fromPixelFormat(formats::YUV420)[0];
 
 		LOG(RPI, Debug) << "Setting ISP Output1 (internal) to "
 				<< output1Format;
diff --git a/src/libcamera/pipeline/rkisp1/rkisp1_path.cpp b/src/libcamera/pipeline/rkisp1/rkisp1_path.cpp
index 6f175758..f4e71bab 100644
--- a/src/libcamera/pipeline/rkisp1/rkisp1_path.cpp
+++ b/src/libcamera/pipeline/rkisp1/rkisp1_path.cpp
@@ -81,7 +81,7 @@ CameraConfiguration::Status RkISP1Path::validate(StreamConfiguration *cfg)
 	cfg->bufferCount = RKISP1_BUFFER_COUNT;
 
 	V4L2DeviceFormat format;
-	format.fourcc = V4L2PixelFormat::fromPixelFormat(cfg->pixelFormat);
+	format.fourcc = V4L2PixelFormat::fromPixelFormat(cfg->pixelFormat)[0];
 	format.size = cfg->size;
 
 	int ret = video_->tryFormat(&format);
@@ -147,7 +147,7 @@ int RkISP1Path::configure(const StreamConfiguration &config,
 
 	const PixelFormatInfo &info = PixelFormatInfo::info(config.pixelFormat);
 	V4L2DeviceFormat outputFormat;
-	outputFormat.fourcc = V4L2PixelFormat::fromPixelFormat(config.pixelFormat);
+	outputFormat.fourcc = V4L2PixelFormat::fromPixelFormat(config.pixelFormat)[0];
 	outputFormat.size = config.size;
 	outputFormat.planesCount = info.numPlanes();
 
@@ -156,7 +156,7 @@ int RkISP1Path::configure(const StreamConfiguration &config,
 		return ret;
 
 	if (outputFormat.size != config.size ||
-	    outputFormat.fourcc != V4L2PixelFormat::fromPixelFormat(config.pixelFormat)) {
+	    outputFormat.fourcc != V4L2PixelFormat::fromPixelFormat(config.pixelFormat)[0]) {
 		LOG(RkISP1, Error)
 			<< "Unable to configure capture in " << config.toString();
 		return -EINVAL;
diff --git a/src/libcamera/pipeline/simple/converter.cpp b/src/libcamera/pipeline/simple/converter.cpp
index 62d173bb..47e2150b 100644
--- a/src/libcamera/pipeline/simple/converter.cpp
+++ b/src/libcamera/pipeline/simple/converter.cpp
@@ -46,7 +46,7 @@ int SimpleConverter::Stream::configure(const StreamConfiguration &inputCfg,
 				       const StreamConfiguration &outputCfg)
 {
 	V4L2PixelFormat videoFormat =
-		V4L2PixelFormat::fromPixelFormat(inputCfg.pixelFormat);
+		V4L2PixelFormat::fromPixelFormat(inputCfg.pixelFormat)[0];
 
 	V4L2DeviceFormat format;
 	format.fourcc = videoFormat;
@@ -71,7 +71,7 @@ int SimpleConverter::Stream::configure(const StreamConfiguration &inputCfg,
 	}
 
 	/* Set the pixel format and size on the output. */
-	videoFormat = V4L2PixelFormat::fromPixelFormat(outputCfg.pixelFormat);
+	videoFormat = V4L2PixelFormat::fromPixelFormat(outputCfg.pixelFormat)[0];
 	format = {};
 	format.fourcc = videoFormat;
 	format.size = outputCfg.size;
@@ -210,7 +210,7 @@ std::vector<PixelFormat> SimpleConverter::formats(PixelFormat input)
 	 * enumerate the conversion capabilities on its output (V4L2 capture).
 	 */
 	V4L2DeviceFormat v4l2Format;
-	v4l2Format.fourcc = V4L2PixelFormat::fromPixelFormat(input);
+	v4l2Format.fourcc = V4L2PixelFormat::fromPixelFormat(input)[0];
 	v4l2Format.size = { 1, 1 };
 
 	int ret = m2m_->output()->setFormat(&v4l2Format);
@@ -287,7 +287,7 @@ SimpleConverter::strideAndFrameSize(const PixelFormat &pixelFormat,
 				    const Size &size)
 {
 	V4L2DeviceFormat format;
-	format.fourcc = V4L2PixelFormat::fromPixelFormat(pixelFormat);
+	format.fourcc = V4L2PixelFormat::fromPixelFormat(pixelFormat)[0];
 	format.size = size;
 
 	int ret = m2m_->capture()->tryFormat(&format);
diff --git a/src/libcamera/pipeline/simple/simple.cpp b/src/libcamera/pipeline/simple/simple.cpp
index bc0cb1a0..33a7b4e5 100644
--- a/src/libcamera/pipeline/simple/simple.cpp
+++ b/src/libcamera/pipeline/simple/simple.cpp
@@ -918,7 +918,7 @@ CameraConfiguration::Status SimpleCameraConfiguration::validate()
 				return Invalid;
 		} else {
 			V4L2DeviceFormat format;
-			format.fourcc = V4L2PixelFormat::fromPixelFormat(cfg.pixelFormat);
+			format.fourcc = V4L2PixelFormat::fromPixelFormat(cfg.pixelFormat)[0];
 			format.size = cfg.size;
 
 			int ret = data_->video_->tryFormat(&format);
@@ -1028,7 +1028,7 @@ int SimplePipelineHandler::configure(Camera *camera, CameraConfiguration *c)
 		return ret;
 
 	/* Configure the video node. */
-	V4L2PixelFormat videoFormat = V4L2PixelFormat::fromPixelFormat(pipeConfig->captureFormat);
+	V4L2PixelFormat videoFormat = V4L2PixelFormat::fromPixelFormat(pipeConfig->captureFormat)[0];
 
 	V4L2DeviceFormat captureFormat;
 	captureFormat.fourcc = videoFormat;
diff --git a/src/libcamera/pipeline/uvcvideo/uvcvideo.cpp b/src/libcamera/pipeline/uvcvideo/uvcvideo.cpp
index 53b2f23a..338aff02 100644
--- a/src/libcamera/pipeline/uvcvideo/uvcvideo.cpp
+++ b/src/libcamera/pipeline/uvcvideo/uvcvideo.cpp
@@ -149,7 +149,7 @@ CameraConfiguration::Status UVCCameraConfiguration::validate()
 	cfg.bufferCount = 4;
 
 	V4L2DeviceFormat format;
-	format.fourcc = V4L2PixelFormat::fromPixelFormat(cfg.pixelFormat);
+	format.fourcc = V4L2PixelFormat::fromPixelFormat(cfg.pixelFormat)[0];
 	format.size = cfg.size;
 
 	int ret = data_->video_->tryFormat(&format);
@@ -205,7 +205,7 @@ int PipelineHandlerUVC::configure(Camera *camera, CameraConfiguration *config)
 	int ret;
 
 	V4L2DeviceFormat format;
-	format.fourcc = V4L2PixelFormat::fromPixelFormat(cfg.pixelFormat);
+	format.fourcc = V4L2PixelFormat::fromPixelFormat(cfg.pixelFormat)[0];
 	format.size = cfg.size;
 
 	ret = data->video_->setFormat(&format);
@@ -213,7 +213,7 @@ int PipelineHandlerUVC::configure(Camera *camera, CameraConfiguration *config)
 		return ret;
 
 	if (format.size != cfg.size ||
-	    format.fourcc != V4L2PixelFormat::fromPixelFormat(cfg.pixelFormat))
+	    format.fourcc != V4L2PixelFormat::fromPixelFormat(cfg.pixelFormat)[0])
 		return -EINVAL;
 
 	cfg.setStream(&data->stream_);
diff --git a/src/libcamera/pipeline/vimc/vimc.cpp b/src/libcamera/pipeline/vimc/vimc.cpp
index 3379ac5c..b88b30ff 100644
--- a/src/libcamera/pipeline/vimc/vimc.cpp
+++ b/src/libcamera/pipeline/vimc/vimc.cpp
@@ -171,7 +171,7 @@ CameraConfiguration::Status VimcCameraConfiguration::validate()
 	cfg.bufferCount = 4;
 
 	V4L2DeviceFormat format;
-	format.fourcc = V4L2PixelFormat::fromPixelFormat(cfg.pixelFormat);
+	format.fourcc = V4L2PixelFormat::fromPixelFormat(cfg.pixelFormat)[0];
 	format.size = cfg.size;
 
 	int ret = data_->video_->tryFormat(&format);
@@ -275,7 +275,7 @@ int PipelineHandlerVimc::configure(Camera *camera, CameraConfiguration *config)
 		return ret;
 
 	V4L2DeviceFormat format;
-	format.fourcc = V4L2PixelFormat::fromPixelFormat(cfg.pixelFormat);
+	format.fourcc = V4L2PixelFormat::fromPixelFormat(cfg.pixelFormat)[0];
 	format.size = cfg.size;
 
 	ret = data->video_->setFormat(&format);
@@ -283,7 +283,7 @@ int PipelineHandlerVimc::configure(Camera *camera, CameraConfiguration *config)
 		return ret;
 
 	if (format.size != cfg.size ||
-	    format.fourcc != V4L2PixelFormat::fromPixelFormat(cfg.pixelFormat))
+	    format.fourcc != V4L2PixelFormat::fromPixelFormat(cfg.pixelFormat)[0])
 		return -EINVAL;
 
 	/*
@@ -598,7 +598,7 @@ int VimcCameraData::allocateMockIPABuffers()
 	constexpr unsigned int kBufCount = 2;
 
 	V4L2DeviceFormat format;
-	format.fourcc = V4L2PixelFormat::fromPixelFormat(formats::BGR888);
+	format.fourcc = V4L2PixelFormat::fromPixelFormat(formats::BGR888)[0];
 	format.size = Size (160, 120);
 
 	int ret = video_->setFormat(&format);
diff --git a/src/libcamera/v4l2_pixelformat.cpp b/src/libcamera/v4l2_pixelformat.cpp
index cf6c1858..7ab63f09 100644
--- a/src/libcamera/v4l2_pixelformat.cpp
+++ b/src/libcamera/v4l2_pixelformat.cpp
@@ -302,26 +302,26 @@ PixelFormat V4L2PixelFormat::toPixelFormat() const
 }
 
 /**
- * \brief Convert \a pixelFormat to its corresponding V4L2PixelFormat
+ * \brief Convert \a pixelFormat to a list of corresponding V4L2PixelFormat
  * \param[in] pixelFormat The PixelFormat to convert
  * \param[in] multiplanar V4L2 Multiplanar API support flag
  *
- * Multiple V4L2 formats may exist for one PixelFormat when the format uses
- * multiple planes, as V4L2 defines separate 4CCs for contiguous and separate
- * planes formats. Set the \a multiplanar parameter to false to select a format
- * with contiguous planes, or to true to select a format with non-contiguous
- * planes.
+ * Multiple V4L2 formats may exist for one PixelFormat. This function returns
+ * the list of V4L2 formats and distinguish if the format describes contiguous
+ * or non-contiguous planes as V4L2 defines separate 4CCs for the two variants.
+ * This function uses the \a multiplanar argument, defaulted to false,
+ * to select formats with non-contiguous or contiguous planes.
  *
  * \return The V4L2PixelFormat corresponding to \a pixelFormat
  */
-V4L2PixelFormat V4L2PixelFormat::fromPixelFormat(const PixelFormat &pixelFormat,
-						 bool multiplanar)
+std::vector<V4L2PixelFormat> V4L2PixelFormat::fromPixelFormat(const PixelFormat &pixelFormat,
+							      bool multiplanar)
 {
 	const PixelFormatInfo &info = PixelFormatInfo::info(pixelFormat);
 	if (!info.isValid())
-		return V4L2PixelFormat();
+		return {};
 
-	return multiplanar ? info.v4l2Formats.multi[0] : info.v4l2Formats.single[0];
+	return multiplanar ? info.v4l2Formats.multi : info.v4l2Formats.single;
 }
 
 /**
diff --git a/src/v4l2/v4l2_camera_proxy.cpp b/src/v4l2/v4l2_camera_proxy.cpp
index 26a227da..55ff62cd 100644
--- a/src/v4l2/v4l2_camera_proxy.cpp
+++ b/src/v4l2/v4l2_camera_proxy.cpp
@@ -182,7 +182,7 @@ void V4L2CameraProxy::setFmtFromConfig(const StreamConfiguration &streamConfig)
 
 	v4l2PixFormat_.width        = size.width;
 	v4l2PixFormat_.height       = size.height;
-	v4l2PixFormat_.pixelformat  = V4L2PixelFormat::fromPixelFormat(streamConfig.pixelFormat);
+	v4l2PixFormat_.pixelformat  = V4L2PixelFormat::fromPixelFormat(streamConfig.pixelFormat)[0];
 	v4l2PixFormat_.field        = V4L2_FIELD_NONE;
 	v4l2PixFormat_.bytesperline = streamConfig.stride;
 	v4l2PixFormat_.sizeimage    = streamConfig.frameSize;
@@ -290,7 +290,7 @@ int V4L2CameraProxy::vidioc_enum_fmt(V4L2CameraFile *file, struct v4l2_fmtdesc *
 		return -EINVAL;
 
 	PixelFormat format = streamConfig_.formats().pixelformats()[arg->index];
-	V4L2PixelFormat v4l2Format = V4L2PixelFormat::fromPixelFormat(format);
+	V4L2PixelFormat v4l2Format = V4L2PixelFormat::fromPixelFormat(format)[0];
 
 	arg->flags = format == formats::MJPEG ? V4L2_FMT_FLAG_COMPRESSED : 0;
 	utils::strlcpy(reinterpret_cast<char *>(arg->description),
@@ -333,7 +333,7 @@ int V4L2CameraProxy::tryFormat(struct v4l2_format *arg)
 
 	arg->fmt.pix.width        = config.size.width;
 	arg->fmt.pix.height       = config.size.height;
-	arg->fmt.pix.pixelformat  = V4L2PixelFormat::fromPixelFormat(config.pixelFormat);
+	arg->fmt.pix.pixelformat  = V4L2PixelFormat::fromPixelFormat(config.pixelFormat)[0];
 	arg->fmt.pix.field        = V4L2_FIELD_NONE;
 	arg->fmt.pix.bytesperline = config.stride;
 	arg->fmt.pix.sizeimage    = config.frameSize;
diff --git a/test/libtest/buffer_source.cpp b/test/libtest/buffer_source.cpp
index 1b261697..84f1169c 100644
--- a/test/libtest/buffer_source.cpp
+++ b/test/libtest/buffer_source.cpp
@@ -72,7 +72,7 @@ int BufferSource::allocate(const StreamConfiguration &config)
 	}
 
 	format.size = config.size;
-	format.fourcc = V4L2PixelFormat::fromPixelFormat(config.pixelFormat);
+	format.fourcc = V4L2PixelFormat::fromPixelFormat(config.pixelFormat)[0];
 	if (video->setFormat(&format)) {
 		std::cout << "Failed to set format on output device" << std::endl;
 		return TestFail;