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Add support for NV12 encoding in cv_bridge #552

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ec6fef6
Add NV12 Support to cv_bridge
quic-zhanlin Jul 30, 2025
e344f6a
Add support for NV12 encoding in utest2
quic-zhanlin Aug 4, 2025
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41 changes: 33 additions & 8 deletions cv_bridge/src/cv_bridge.cpp
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Original file line number Diff line number Diff line change
Expand Up @@ -54,6 +54,23 @@ namespace enc = sensor_msgs::image_encodings;
namespace cv_bridge
{

static inline bool isPlanar(const std::string & encoding)
{
return encoding == enc::NV12 || encoding == enc::NV21 || encoding == enc::NV24;
}

static inline float getHeightScaling(const std::string & encoding)
{
if (isPlanar(encoding)) {
if (encoding == enc::NV12 ||
encoding == enc::NV21)
{
return 1.5f;
}
}
return 1.0f;
}

static int depthStrToInt(const std::string depth)
{
if (depth == "8U") {
Expand Down Expand Up @@ -99,6 +116,7 @@ int getCvType(const std::string & encoding)
// Miscellaneous
if (encoding == enc::YUV422) {return CV_8UC2;}
if (encoding == enc::YUV422_YUY2) {return CV_8UC2;}
if (encoding == enc::NV12) {return CV_8UC1;}

// Check all the generic content encodings
std::cmatch m;
Expand All @@ -120,7 +138,7 @@ int getCvType(const std::string & encoding)

/// @cond DOXYGEN_IGNORE

enum Encoding { INVALID = -1, GRAY = 0, RGB, BGR, RGBA, BGRA, YUV422, YUV422_YUY2, BAYER_RGGB, BAYER_BGGR,
enum Encoding { INVALID = -1, GRAY = 0, RGB, BGR, RGBA, BGRA, YUV422, YUV422_YUY2, NV12, BAYER_RGGB, BAYER_BGGR,
BAYER_GBRG, BAYER_GRBG, MAX_ENCODING};

Encoding getEncoding(const std::string & encoding)
Expand All @@ -132,6 +150,7 @@ Encoding getEncoding(const std::string & encoding)
if ((encoding == enc::RGBA8) || (encoding == enc::RGBA16)) {return RGBA;}
if (encoding == enc::YUV422) {return YUV422;}
if (encoding == enc::YUV422_YUY2) {return YUV422_YUY2;}
if (encoding == enc::NV12) {return NV12;}

if ((encoding == enc::BAYER_RGGB8) || (encoding == enc::BAYER_RGGB16)) {return BAYER_RGGB;}
if ((encoding == enc::BAYER_BGGR8) || (encoding == enc::BAYER_BGGR16)) {return BAYER_BGGR;}
Expand Down Expand Up @@ -192,6 +211,12 @@ std::map<std::pair<Encoding, Encoding>, std::vector<int>> getConversionCodes()
res[std::make_pair(YUV422_YUY2, RGBA)].push_back(cv::COLOR_YUV2RGBA_YUY2);
res[std::make_pair(YUV422_YUY2, BGRA)].push_back(cv::COLOR_YUV2BGRA_YUY2);

res[std::make_pair(NV12, GRAY)].push_back(cv::COLOR_YUV2GRAY_NV12);
res[std::make_pair(NV12, RGB)].push_back(cv::COLOR_YUV2RGB_NV12);
res[std::make_pair(NV12, BGR)].push_back(cv::COLOR_YUV2BGR_NV12);
res[std::make_pair(NV12, RGBA)].push_back(cv::COLOR_YUV2RGBA_NV12);
res[std::make_pair(NV12, BGRA)].push_back(cv::COLOR_YUV2BGRA_NV12);

// Deal with Bayer
res[std::make_pair(BAYER_RGGB, GRAY)].push_back(cv::COLOR_BayerBG2GRAY);
res[std::make_pair(BAYER_RGGB, RGB)].push_back(cv::COLOR_BayerBG2RGB);
Expand All @@ -217,9 +242,9 @@ const std::vector<int> getConversionCode(std::string src_encoding, std::string d
Encoding src_encod = getEncoding(src_encoding);
Encoding dst_encod = getEncoding(dst_encoding);
bool is_src_color_format = enc::isColor(src_encoding) || enc::isMono(src_encoding) ||
enc::isBayer(src_encoding) || (src_encoding == enc::YUV422) || (src_encoding == enc::YUV422_YUY2);
enc::isBayer(src_encoding) || (src_encoding == enc::YUV422) || (src_encoding == enc::YUV422_YUY2) || (src_encoding == enc::NV12);
bool is_dst_color_format = enc::isColor(dst_encoding) || enc::isMono(dst_encoding) ||
enc::isBayer(dst_encoding) || (dst_encoding == enc::YUV422) || (dst_encoding == enc::YUV422_YUY2);
enc::isBayer(dst_encoding) || (dst_encoding == enc::YUV422) || (dst_encoding == enc::YUV422_YUY2) || (dst_encoding == enc::NV12);
bool is_num_channels_the_same =
(enc::numChannels(src_encoding) == enc::numChannels(dst_encoding));

Expand Down Expand Up @@ -288,15 +313,15 @@ cv::Mat matFromImage(const sensor_msgs::msg::Image & source)
throw Exception(ss.str());
}

if (source.height * source.step != source.data.size()) {
if (source.height * source.step * getHeightScaling(source.encoding) != source.data.size()) {
std::stringstream ss;
ss << "Image is wrongly formed: height * step != size or " << source.height << " * " <<
source.step << " != " << source.data.size();
ss << "Image is wrongly formed: height * step * HeightScaling != size or " << source.height << " * " <<
source.step << " * " << getHeightScaling(source.encoding) << " != " << source.data.size();
throw Exception(ss.str());
}

// If the endianness is the same as locally, share the data
cv::Mat mat(source.height, source.width, source_type, const_cast<uchar *>(&source.data[0]),
cv::Mat mat(source.height * getHeightScaling(source.encoding), source.width, source_type, const_cast<uchar *>(&source.data[0]),
source.step);

if ((rcpputils::endian::native == rcpputils::endian::big && source.is_bigendian) ||
Expand Down Expand Up @@ -389,7 +414,7 @@ sensor_msgs::msg::Image::SharedPtr CvImage::toImageMsg() const
void CvImage::toImageMsg(sensor_msgs::msg::Image & ros_image) const
{
ros_image.header = header;
ros_image.height = image.rows;
ros_image.height = image.rows / getHeightScaling(encoding);
ros_image.width = image.cols;
ros_image.encoding = encoding;
ros_image.is_bigendian = (rcpputils::endian::native == rcpputils::endian::big);
Expand Down
40 changes: 31 additions & 9 deletions cv_bridge/test/utest2.cpp
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Original file line number Diff line number Diff line change
Expand Up @@ -45,6 +45,23 @@

using namespace sensor_msgs::image_encodings;

static inline bool isPlanar(const std::string & encoding)
{
return encoding == NV12 || encoding == NV21 || encoding == NV24;
}

static inline float getHeightScaling(const std::string & encoding)
{
if (isPlanar(encoding)) {
if (encoding == NV12 ||
encoding == NV21)
{
return 1.5f;
}
}
return 1.0f;
}

bool isUnsigned(const std::string & encoding)
{
return encoding == RGB8 || encoding == RGBA8 || encoding == RGB16 || encoding == RGBA16 ||
Expand All @@ -71,8 +88,8 @@ getEncodings()
TYPE_64FC1, /*TYPE_64FC2,*/ TYPE_64FC3, TYPE_64FC4,
// BAYER_RGGB8, BAYER_BGGR8, BAYER_GBRG8, BAYER_GRBG8,
// BAYER_RGGB16, BAYER_BGGR16, BAYER_GBRG16, BAYER_GRBG16,
YUV422, YUV422_YUY2};
return std::vector<std::string>(encodings, encodings + 48 - 8 - 7);
YUV422, YUV422_YUY2, NV12};
return std::vector<std::string>(encodings, encodings + 48 - 8 - 6);
}

TEST(OpencvTests, testCase_encode_decode)
Expand All @@ -82,8 +99,9 @@ TEST(OpencvTests, testCase_encode_decode)
std::string src_encoding = encodings[i];
bool is_src_color_format = isColor(src_encoding) || isMono(src_encoding) ||
(src_encoding == sensor_msgs::image_encodings::YUV422) ||
(src_encoding == sensor_msgs::image_encodings::YUV422_YUY2);
cv::Mat image_original(cv::Size(400, 400), cv_bridge::getCvType(src_encoding));
(src_encoding == sensor_msgs::image_encodings::YUV422_YUY2) ||
(src_encoding == sensor_msgs::image_encodings::NV12);
cv::Mat image_original(cv::Size(400, 400 * getHeightScaling(src_encoding)), cv_bridge::getCvType(src_encoding));
cv::RNG r(77);
r.fill(image_original, cv::RNG::UNIFORM, 0, 127);

Expand All @@ -97,7 +115,8 @@ TEST(OpencvTests, testCase_encode_decode)
std::string dst_encoding = encodings[j];
bool is_dst_color_format = isColor(dst_encoding) || isMono(dst_encoding) ||
(dst_encoding == sensor_msgs::image_encodings::YUV422) ||
(dst_encoding == sensor_msgs::image_encodings::YUV422_YUY2);
(dst_encoding == sensor_msgs::image_encodings::YUV422_YUY2) ||
(dst_encoding == sensor_msgs::image_encodings::NV12);
bool is_num_channels_the_same = (numChannels(src_encoding) == numChannels(dst_encoding));

cv_bridge::CvImageConstPtr cv_image;
Expand Down Expand Up @@ -127,21 +146,24 @@ TEST(OpencvTests, testCase_encode_decode)
EXPECT_THROW((void)cvtColor(cv_image, src_encoding)->image, cv_bridge::Exception);
continue;
}
// We do not support conversion to YUV422 for now, except from YUV422
// We do not support conversion to YUV422/NV12 for now, except from YUV422/NV12
if (((dst_encoding == YUV422) && (src_encoding != YUV422)) ||
((dst_encoding == YUV422_YUY2) && (src_encoding != YUV422_YUY2))) {
((dst_encoding == YUV422_YUY2) && (src_encoding != YUV422_YUY2)) ||
((dst_encoding == NV12) && (src_encoding != NV12))) {
EXPECT_THROW(cv_bridge::toCvShare(image_msg, dst_encoding), cv_bridge::Exception);
continue;
}

cv_image = cv_bridge::toCvShare(image_msg, dst_encoding);

// We do not support conversion to YUV422 for now, except from YUV422
// We do not support conversion to YUV422/NV12 for now, except from YUV422/NV12
if (((src_encoding == YUV422) && (dst_encoding != YUV422)) ||
((src_encoding == YUV422_YUY2) && (dst_encoding != YUV422_YUY2))){
((src_encoding == YUV422_YUY2) && (dst_encoding != YUV422_YUY2)) ||
((src_encoding == NV12) && (dst_encoding != NV12))){
EXPECT_THROW((void)cvtColor(cv_image, src_encoding)->image, cv_bridge::Exception);
continue;
}

}
// And convert back to a cv::Mat
image_back = cvtColor(cv_image, src_encoding)->image;
Expand Down