libcamera: v4l2_videodevice: Reintroduce toV4L2PixelFormat()

This is a partial revert of commit 395d43d6d7 ("libcamera:
v4l2_videodevice: Drop toV4L2PixelFormat()")

The function was removed because it incorrectly maps non-contiguous V4L2
format variants (ie V4L2_PIX_FMT_YUV420M) to the API version supported
by the video device (singleplanar API and multiplanar API).  It was
decided at the time to remove the function and let its users call
directly V4L2PixelFormat::fromPixelFormat() which accepts a
'multiplanar' flags.

As we aim to associate multiple V4L2PixelFormat to a single libcamera
format, the next patches will verify which of them is actually supported
by the video device. For now, return the contiguous version
unconditionally.

Re-introduce V4L2VideoDevice::toV4L2PixelFormat() and convert all
the V4L2PixelFormat::fromPixelFormat() users to use it.

The V4L2 compatibility layer is the only outlier as it doesn't have a
video device to poke, hence it still uses
V4L2PixelFormat::fromPixelFormat().

Next patches will implement the device format matching logic and handle
the non-contiguous plane issue in V4L2VideoDevice::toV4L2PixelFormat().

Signed-off-by: Jacopo Mondi <jacopo@jmondi.org>
Reviewed-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Tested-by: Paul Elder <paul.elder@ideasonboard.com>

Documentation/guides/pipeline-handler.rst

@@ -971,7 +971,8 @@ with the fourcc and size attributes to apply directly to the capture device
 node. The fourcc attribute is a `V4L2PixelFormat`_ and differs from the
 ``libcamera::PixelFormat``. Converting the format requires knowledge of the
 plane configuration for multiplanar formats, so you must explicitly convert it
-using the helper ``V4L2PixelFormat::fromPixelFormat()``.
+using the helper ``V4L2VideoDevice::toV4L2PixelFormat()`` provided by the
+V4L2VideoDevice instance that the format will be applied on.
 
 .. _V4L2DeviceFormat: https://libcamera.org/api-html/classlibcamera_1_1V4L2DeviceFormat.html
 .. _V4L2PixelFormat: https://libcamera.org/api-html/classlibcamera_1_1V4L2PixelFormat.html
@@ -981,7 +982,7 @@ Add the following code beneath the code from above:
 .. code-block:: cpp
 
    V4L2DeviceFormat format = {};
-   format.fourcc = V4L2PixelFormat::fromPixelFormat(cfg.pixelFormat);
+   format.fourcc = data->video_->toV4L2PixelFormat(cfg.pixelFormat);
    format.size = cfg.size;
 
 Set the video device format defined above using the
@@ -1001,7 +1002,7 @@ Continue the implementation with the following code:
           return ret;
 
    if (format.size != cfg.size ||
-          format.fourcc != V4L2PixelFormat::fromPixelFormat(cfg.pixelFormat))
+          format.fourcc != data->video_->toV4L2PixelFormat(cfg.pixelFormat))
           return -EINVAL;
 
 Finally, store and set stream-specific data reflecting the state of the stream.

include/libcamera/internal/v4l2_videodevice.h

@@ -228,6 +228,8 @@ public:
 	static std::unique_ptr<V4L2VideoDevice>
 	fromEntityName(const MediaDevice *media, const std::string &entity);
 
+	V4L2PixelFormat toV4L2PixelFormat(const PixelFormat &pixelFormat) const;
+
 protected:
 	std::string logPrefix() const override;
 

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 = output_->toV4L2PixelFormat(itInfo->second);
 	outputFormat->size = sensorFormat.size;
 	outputFormat->planesCount = 1;
 

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 = dev->toV4L2PixelFormat(formats::NV12);
 	outputFormat->size = cfg.size;
 	outputFormat->planesCount = 2;
 

src/libcamera/pipeline/raspberrypi/raspberrypi.cpp

@@ -90,13 +90,14 @@ PixelFormat mbusCodeToPixelFormat(unsigned int mbus_code,
 	return pix;
 }
 
-V4L2DeviceFormat toV4L2DeviceFormat(const V4L2SubdeviceFormat &format,
+V4L2DeviceFormat toV4L2DeviceFormat(const V4L2VideoDevice *dev,
+				    const V4L2SubdeviceFormat &format,
 				    BayerFormat::Packing packingReq)
 {
 	const PixelFormat pix = mbusCodeToPixelFormat(format.mbus_code, packingReq);
 	V4L2DeviceFormat deviceFormat;
 
-	deviceFormat.fourcc = V4L2PixelFormat::fromPixelFormat(pix);
+	deviceFormat.fourcc = dev->toV4L2PixelFormat(pix);
 	deviceFormat.size = format.size;
 	deviceFormat.colorSpace = format.colorSpace;
 	return deviceFormat;
@@ -422,15 +423,15 @@ CameraConfiguration::Status RPiCameraConfiguration::validate()
 			 * Calculate the best sensor mode we can use based on
 			 * the user request.
 			 */
+			V4L2VideoDevice *unicam = data_->unicam_[Unicam::Image].dev();
 			const PixelFormatInfo &info = PixelFormatInfo::info(cfg.pixelFormat);
 			unsigned int bitDepth = info.isValid() ? info.bitsPerPixel : defaultRawBitDepth;
 			V4L2SubdeviceFormat sensorFormat = findBestFormat(data_->sensorFormats_, cfg.size, bitDepth);
 			BayerFormat::Packing packing = BayerFormat::Packing::CSI2;
 			if (info.isValid() && !info.packed)
 				packing = BayerFormat::Packing::None;
-			V4L2DeviceFormat unicamFormat = toV4L2DeviceFormat(sensorFormat,
+			V4L2DeviceFormat unicamFormat = toV4L2DeviceFormat(unicam, sensorFormat, packing);
-									   packing);
+			int ret = unicam->tryFormat(&unicamFormat);
-			int ret = data_->unicam_[Unicam::Image].dev()->tryFormat(&unicamFormat);
 			if (ret)
 				return Invalid;
 
@@ -516,14 +517,14 @@ CameraConfiguration::Status RPiCameraConfiguration::validate()
 
 		V4L2VideoDevice::Formats fmts = dev->formats();
 
-		if (fmts.find(V4L2PixelFormat::fromPixelFormat(cfgPixFmt)) == fmts.end()) {
+		if (fmts.find(dev->toV4L2PixelFormat(cfgPixFmt)) == 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 = dev->toV4L2PixelFormat(cfg.pixelFormat);
 		format.size = cfg.size;
 		format.colorSpace = cfg.colorSpace;
 
@@ -751,8 +752,9 @@ int PipelineHandlerRPi::configure(Camera *camera, CameraConfiguration *config)
 	if (ret)
 		return ret;
 
-	V4L2DeviceFormat unicamFormat = toV4L2DeviceFormat(sensorFormat, packing);
+	V4L2VideoDevice *unicam = data->unicam_[Unicam::Image].dev();
-	ret = data->unicam_[Unicam::Image].dev()->setFormat(&unicamFormat);
+	V4L2DeviceFormat unicamFormat = toV4L2DeviceFormat(unicam, sensorFormat, packing);
+	ret = unicam->setFormat(&unicamFormat);
 	if (ret)
 		return ret;
 
@@ -783,7 +785,7 @@ 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 = stream->dev()->toV4L2PixelFormat(cfg.pixelFormat);
 		format.size = cfg.size;
 		format.fourcc = fourcc;
 		format.colorSpace = cfg.colorSpace;
@@ -826,13 +828,15 @@ int PipelineHandlerRPi::configure(Camera *camera, CameraConfiguration *config)
 	 * statistics coming from the hardware.
 	 */
 	if (!output0Set) {
+		V4L2VideoDevice *dev = data->isp_[Isp::Output0].dev();
+
 		maxSize = Size(320, 240);
 		format = {};
 		format.size = maxSize;
-		format.fourcc = V4L2PixelFormat::fromPixelFormat(formats::YUV420);
+		format.fourcc = dev->toV4L2PixelFormat(formats::YUV420);
 		/* No one asked for output, so the color space doesn't matter. */
 		format.colorSpace = ColorSpace::Jpeg;
-		ret = data->isp_[Isp::Output0].dev()->setFormat(&format);
+		ret = dev->setFormat(&format);
 		if (ret) {
 			LOG(RPI, Error)
 				<< "Failed to set default format on ISP Output0: "
@@ -856,18 +860,20 @@ int PipelineHandlerRPi::configure(Camera *camera, CameraConfiguration *config)
 	 * colour denoise will not run.
 	 */
 	if (!output1Set) {
+		V4L2VideoDevice *dev = data->isp_[Isp::Output1].dev();
+
 		V4L2DeviceFormat output1Format;
 		constexpr Size maxDimensions(1200, 1200);
 		const Size limit = maxDimensions.boundedToAspectRatio(format.size);
 
 		output1Format.size = (format.size / 2).boundedTo(limit).alignedDownTo(2, 2);
 		output1Format.colorSpace = format.colorSpace;
-		output1Format.fourcc = V4L2PixelFormat::fromPixelFormat(formats::YUV420);
+		output1Format.fourcc = dev->toV4L2PixelFormat(formats::YUV420);
 
 		LOG(RPI, Debug) << "Setting ISP Output1 (internal) to "
 				<< output1Format;
 
-		ret = data->isp_[Isp::Output1].dev()->setFormat(&output1Format);
+		ret = dev->setFormat(&output1Format);
 		if (ret) {
 			LOG(RPI, Error) << "Failed to set format on ISP Output1: "
 					<< ret;

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 = video_->toV4L2PixelFormat(cfg->pixelFormat);
 	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 = video_->toV4L2PixelFormat(config.pixelFormat);
 	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 != video_->toV4L2PixelFormat(config.pixelFormat)) {
 		LOG(RkISP1, Error)
 			<< "Unable to configure capture in " << config.toString();
 		return -EINVAL;

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);
+		m2m_->output()->toV4L2PixelFormat(inputCfg.pixelFormat);
 
 	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 = m2m_->capture()->toV4L2PixelFormat(outputCfg.pixelFormat);
 	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 = m2m_->output()->toV4L2PixelFormat(input);
 	v4l2Format.size = { 1, 1 };
 
 	int ret = m2m_->output()->setFormat(&v4l2Format);
@@ -220,7 +220,7 @@ std::vector<PixelFormat> SimpleConverter::formats(PixelFormat input)
 		return {};
 	}
 
-	if (v4l2Format.fourcc != V4L2PixelFormat::fromPixelFormat(input)) {
+	if (v4l2Format.fourcc != m2m_->output()->toV4L2PixelFormat(input)) {
 		LOG(SimplePipeline, Debug)
 			<< "Input format " << input << " not supported.";
 		return {};
@@ -287,7 +287,7 @@ SimpleConverter::strideAndFrameSize(const PixelFormat &pixelFormat,
 				    const Size &size)
 {
 	V4L2DeviceFormat format;
-	format.fourcc = V4L2PixelFormat::fromPixelFormat(pixelFormat);
+	format.fourcc = m2m_->capture()->toV4L2PixelFormat(pixelFormat);
 	format.size = size;
 
 	int ret = m2m_->capture()->tryFormat(&format);

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 = data_->video_->toV4L2PixelFormat(cfg.pixelFormat);
 			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 = video->toV4L2PixelFormat(pipeConfig->captureFormat);
 
 	V4L2DeviceFormat captureFormat;
 	captureFormat.fourcc = videoFormat;

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 = data_->video_->toV4L2PixelFormat(cfg.pixelFormat);
 	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 = data->video_->toV4L2PixelFormat(cfg.pixelFormat);
 	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 != data->video_->toV4L2PixelFormat(cfg.pixelFormat))
 		return -EINVAL;
 
 	cfg.setStream(&data->stream_);

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 = data_->video_->toV4L2PixelFormat(cfg.pixelFormat);
 	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 = data->video_->toV4L2PixelFormat(cfg.pixelFormat);
 	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 != data->video_->toV4L2PixelFormat(cfg.pixelFormat))
 		return -EINVAL;
 
 	/*
@@ -598,7 +598,7 @@ int VimcCameraData::allocateMockIPABuffers()
 	constexpr unsigned int kBufCount = 2;
 
 	V4L2DeviceFormat format;
-	format.fourcc = V4L2PixelFormat::fromPixelFormat(formats::BGR888);
+	format.fourcc = video_->toV4L2PixelFormat(formats::BGR888);
 	format.size = Size (160, 120);
 
 	int ret = video_->setFormat(&format);

src/libcamera/v4l2_videodevice.cpp

@@ -1989,6 +1989,20 @@ V4L2VideoDevice::fromEntityName(const MediaDevice *media,
 	return std::make_unique<V4L2VideoDevice>(mediaEntity);
 }
 
+/**
+ * \brief Convert \a PixelFormat to its corresponding V4L2 FourCC
+ * \param[in] pixelFormat The PixelFormat to convert
+ *
+ * The V4L2 format variant the function returns the contiguous version
+ * unconditionally.
+ *
+ * \return The V4L2_PIX_FMT_* pixel format code corresponding to \a pixelFormat
+ */
+V4L2PixelFormat V4L2VideoDevice::toV4L2PixelFormat(const PixelFormat &pixelFormat) const
+{
+	return V4L2PixelFormat::fromPixelFormat(pixelFormat);
+}
+
 /**
  * \class V4L2M2MDevice
  * \brief Memory-to-Memory video device

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 = video->toV4L2PixelFormat(config.pixelFormat);
 	if (video->setFormat(&format)) {
 		std::cout << "Failed to set format on output device" << std::endl;
 		return TestFail;