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authorLaurent Pinchart <laurent.pinchart@ideasonboard.com>2024-02-26 04:50:15 +0200
committerLaurent Pinchart <laurent.pinchart@ideasonboard.com>2024-03-15 12:54:56 +0200
commitd60fb232588efe9f9aee001faaab35bf5f46bec1 (patch)
tree671aa796d077bc16662cdf465de05db6b77ce96d
parent1a1cf4a2c13a04f23593419ce93e97f9a5bb22d1 (diff)
libcamera: v4l2_subdevice: Expose media bus format info as internal API
The V4L2SubdeviceFormatInfo structure, internal to the v4l2_subdevice.cpp compilation unit, contains information about media bus formats that will be useful in other parts of libcamera. To prepare for this, expose the structure in the v4l2_subdevice.h header and turn it into a class with a similar design as PixelFormatInfo. Signed-off-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com> Reviewed-by: Jacopo Mondi <jacopo.mondi@ideasonboard.com> Reviewed-by: Kieran Bingham <kieran.bingham@ideasonboard.com>
-rw-r--r--include/libcamera/internal/v4l2_subdevice.h13
-rw-r--r--src/libcamera/v4l2_subdevice.cpp92
2 files changed, 75 insertions, 30 deletions
diff --git a/include/libcamera/internal/v4l2_subdevice.h b/include/libcamera/internal/v4l2_subdevice.h
index 17db311b..a4df9ddf 100644
--- a/include/libcamera/internal/v4l2_subdevice.h
+++ b/include/libcamera/internal/v4l2_subdevice.h
@@ -29,6 +29,19 @@ namespace libcamera {
class MediaDevice;
+class MediaBusFormatInfo
+{
+public:
+ bool isValid() const { return code != 0; }
+
+ static const MediaBusFormatInfo &info(uint32_t code);
+
+ const char *name;
+ uint32_t code;
+ unsigned int bitsPerPixel;
+ PixelFormatInfo::ColourEncoding colourEncoding;
+};
+
struct V4L2SubdeviceCapability final : v4l2_subdev_capability {
bool isReadOnly() const
{
diff --git a/src/libcamera/v4l2_subdevice.cpp b/src/libcamera/v4l2_subdevice.cpp
index 1286e7c3..4918e28e 100644
--- a/src/libcamera/v4l2_subdevice.cpp
+++ b/src/libcamera/v4l2_subdevice.cpp
@@ -36,28 +36,40 @@ namespace libcamera {
LOG_DECLARE_CATEGORY(V4L2)
-namespace {
-
-/*
- * \struct MediaBusFormatInfo
+/**
+ * \class MediaBusFormatInfo
* \brief Information about media bus formats
- * \param name Name of MBUS format
- * \param code The media bus format code
- * \param bitsPerPixel Bits per pixel
- * \param colourEncoding Type of colour encoding
+ *
+ * The MediaBusFormatInfo class groups together information describing a media
+ * bus format. It facilitates handling of media bus formats by providing data
+ * commonly used in pipeline handlers.
+ *
+ * \var MediaBusFormatInfo::name
+ * \brief The format name as a human-readable string, used as the text
+ * representation of the format
+ *
+ * \var MediaBusFormatInfo::code
+ * \brief The media bus format code described by this instance (MEDIA_BUS_FMT_*)
+ *
+ * \var MediaBusFormatInfo::bitsPerPixel
+ * \brief The average number of bits per pixel
+ *
+ * The number of bits per pixel averages the total number of bits for all
+ * colour components over the whole image, excluding any padding bits or
+ * padding pixels.
+ *
+ * For formats that transmit multiple or fractional pixels per sample, the
+ * value will differ from the bus width.
+ *
+ * Formats that don't have a fixed number of bits per pixel, such as compressed
+ * formats, report 0 in this field.
+ *
+ * \var MediaBusFormatInfo::colourEncoding
+ * \brief The colour encoding type
*/
-struct MediaBusFormatInfo {
- const char *name;
- uint32_t code;
- unsigned int bitsPerPixel;
- PixelFormatInfo::ColourEncoding colourEncoding;
-};
-/*
- * \var mediaBusFormatInfo
- * \brief A map that associates MediaBusFormatInfo struct to V4L2 media
- * bus codes
- */
+namespace {
+
const std::map<uint32_t, MediaBusFormatInfo> mediaBusFormatInfo{
/* This table is sorted to match the order in linux/media-bus-format.h */
{ MEDIA_BUS_FMT_RGB444_2X8_PADHI_BE, {
@@ -558,6 +570,33 @@ const std::map<uint32_t, MediaBusFormatInfo> mediaBusFormatInfo{
} /* namespace */
/**
+ * \fn bool MediaBusFormatInfo::isValid() const
+ * \brief Check if the media bus format info is valid
+ * \return True if the media bus format info is valid, false otherwise
+ */
+
+/**
+ * \brief Retrieve information about a media bus format
+ * \param[in] code The media bus format code
+ * \return The MediaBusFormatInfo describing the \a code if known, or an invalid
+ * MediaBusFormatInfo otherwise
+ */
+const MediaBusFormatInfo &MediaBusFormatInfo::info(uint32_t code)
+{
+ static const MediaBusFormatInfo invalid{};
+
+ const auto it = mediaBusFormatInfo.find(code);
+ if (it == mediaBusFormatInfo.end()) {
+ LOG(V4L2, Warning)
+ << "Unsupported media bus format "
+ << utils::hex(code, 4);
+ return invalid;
+ }
+
+ return it->second;
+}
+
+/**
* \struct V4L2SubdeviceCapability
* \brief struct v4l2_subdev_capability object wrapper and helpers
*
@@ -653,14 +692,7 @@ const std::string V4L2SubdeviceFormat::toString() const
*/
uint8_t V4L2SubdeviceFormat::bitsPerPixel() const
{
- const auto it = mediaBusFormatInfo.find(mbus_code);
- if (it == mediaBusFormatInfo.end()) {
- LOG(V4L2, Error) << "No information available for format '"
- << *this << "'";
- return 0;
- }
-
- return it->second.bitsPerPixel;
+ return MediaBusFormatInfo::info(mbus_code).bitsPerPixel;
}
/**
@@ -927,9 +959,9 @@ std::optional<ColorSpace> V4L2Subdevice::toColorSpace(const v4l2_mbus_framefmt &
return std::nullopt;
PixelFormatInfo::ColourEncoding colourEncoding;
- auto iter = mediaBusFormatInfo.find(format.code);
- if (iter != mediaBusFormatInfo.end()) {
- colourEncoding = iter->second.colourEncoding;
+ const MediaBusFormatInfo &info = MediaBusFormatInfo::info(format.code);
+ if (info.isValid()) {
+ colourEncoding = info.colourEncoding;
} else {
LOG(V4L2, Warning)
<< "Unknown subdev format "