diff options
| -rw-r--r-- | include/libcamera/internal/formats.h | 6 | ||||
| -rw-r--r-- | src/libcamera/formats.cpp | 102 |
2 files changed, 108 insertions, 0 deletions
diff --git a/include/libcamera/internal/formats.h b/include/libcamera/internal/formats.h index 211da4a3..cad41ad8 100644 --- a/include/libcamera/internal/formats.h +++ b/include/libcamera/internal/formats.h @@ -53,6 +53,12 @@ public: static const PixelFormatInfo &info(const PixelFormat &format); static const PixelFormatInfo &info(const V4L2PixelFormat &format); + unsigned int stride(unsigned int width, unsigned int plane, + unsigned int align = 1) const; + unsigned int frameSize(const Size &size, unsigned int align = 1) const; + unsigned int frameSize(const Size &size, + const std::array<unsigned int, 3> &strides) const; + /* \todo Add support for non-contiguous memory planes */ const char *name; PixelFormat format; diff --git a/src/libcamera/formats.cpp b/src/libcamera/formats.cpp index 48aa2454..3f895a7c 100644 --- a/src/libcamera/formats.cpp +++ b/src/libcamera/formats.cpp @@ -731,4 +731,106 @@ const PixelFormatInfo &PixelFormatInfo::info(const V4L2PixelFormat &format) return info->second; } +/** + * \brief Compute the stride + * \param[in] width The width of the line, in pixels + * \param[in] plane The index of the plane whose stride is to be computed + * \param[in] align The stride alignment, in bytes + * + * The stride is the number of bytes necessary to store a full line of a frame, + * including padding at the end of the line. This function takes into account + * the alignment constraints intrinsic to the format (for instance, the + * SGRBG12_CSI2P format stores two 12-bit pixels in 3 bytes, and thus has a + * required stride alignment of 3 bytes). Additional alignment constraints may + * be specified through the \a align parameter, which will cause the stride to + * be rounded up to the next multiple of \a align. + * + * For multi-planar formats, different planes may have different stride values. + * The \a plane parameter selects which plane to compute the stride for. + * + * \return The number of bytes necessary to store a line, or 0 if the + * PixelFormatInfo instance or the \a plane is not valid + */ +unsigned int PixelFormatInfo::stride(unsigned int width, unsigned int plane, + unsigned int align) const +{ + if (!isValid()) { + LOG(Formats, Warning) << "Invalid pixel format, stride is zero"; + return 0; + } + + if (plane > planes.size() || !planes[plane].bytesPerGroup) { + LOG(Formats, Warning) << "Invalid plane index, stride is zero"; + return 0; + } + + /* ceil(width / pixelsPerGroup) * bytesPerGroup */ + unsigned int stride = (width + pixelsPerGroup - 1) / pixelsPerGroup + * planes[plane].bytesPerGroup; + + /* ceil(stride / align) * align */ + return (stride + align - 1) / align * align; +} + +/** + * \brief Compute the number of bytes necessary to store a frame + * \param[in] size The size of the frame, in pixels + * \param[in] align The stride alignment, in bytes (1 for default alignment) + * + * The frame is computed by adding the product of the line stride and the frame + * height for all planes, taking subsampling and other format characteristics + * into account. Additional stride alignment constraints may be specified + * through the \a align parameter, and will apply to all planes. For more + * complex stride constraints, use the frameSize() overloaded version that takes + * an array of stride values. + * + * \sa stride() + * + * \return The number of bytes necessary to store the frame, or 0 if the + * PixelFormatInfo instance is not valid + */ +unsigned int PixelFormatInfo::frameSize(const Size &size, unsigned int align) const +{ + /* stride * ceil(height / verticalSubSampling) */ + unsigned int sum = 0; + for (unsigned int i = 0; i < 3; i++) { + unsigned int vertSubSample = planes[i].verticalSubSampling; + if (!vertSubSample) + continue; + sum += stride(size.width, i, align) + * ((size.height + vertSubSample - 1) / vertSubSample); + } + + return sum; +} + +/** + * \brief Compute the number of bytes necessary to store a frame + * \param[in] size The size of the frame, in pixels + * \param[in] strides The strides to use for each plane + * + * This function is an overloaded version that takes custom strides for each + * plane, to be used when the device has custom alignment constraints that + * can't be described by just an alignment value. + * + * \return The number of bytes necessary to store the frame, or 0 if the + * PixelFormatInfo instance is not valid + */ +unsigned int +PixelFormatInfo::frameSize(const Size &size, + const std::array<unsigned int, 3> &strides) const +{ + /* stride * ceil(height / verticalSubSampling) */ + unsigned int sum = 0; + for (unsigned int i = 0; i < 3; i++) { + unsigned int vertSubSample = planes[i].verticalSubSampling; + if (!vertSubSample) + continue; + sum += strides[i] + * ((size.height + vertSubSample - 1) / vertSubSample); + } + + return sum; +} + } /* namespace libcamera */ |