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Overview
The VCodecGst C++ library provides video encoding and decoding functions for H264, HEVC (H265), and JPEG codecs for Linux OS, based on GStreamer. The library supports software encoders/decoders and hardware encoders/decoders for Intel, Nvidia Jetson, NXP, and V4L2 platforms (for example, Raspberry PI). The VCodecGst video codec class inherits its interface and data structures from the VCodec interface library. The library depends on the open-source VCodec library (provides codec interface, source code included, Apache 2.0 license), the open-source GStreamer, and the open-source Logger library (provides functions to print logs, source code included, Apache 2.0 license). The library uses the C++17 standard and is compatible with Linux and Windows.
Documentation
Documentation: GO TO DOCUMENTATION
Simple interface
class VCodecGst : public VCodec
{
public:
/// Get library version.
static std::string getVersion();
/// Set parameter value.
bool setParam(VCodecParam id, float value) override;
/// Get parameter value.
float getParam(VCodecParam id) override;
/// Encode video frame.
bool transcode(Frame& src, Frame& dst) override;
/// Execute command.
bool executeCommand(VCodecCommand id) override;
};
Simple example
#include <iostream>
#include <opencv2/opencv.hpp>
#include "VCodecGst.h"
int main(void)
{
// Create codec object and set params.
cr::video::VCodec* encoder = new cr::video::VCodecGst();
encoder->setParam(cr::video::VCodecParam::BITRATE_KBPS, 10000);
encoder->setParam(cr::video::VCodecParam::FPS, 20);
encoder->setParam(cr::video::VCodecParam::GOP, 30);
encoder->setParam(cr::video::VCodecParam::H264_PROFILE, 0);
// Open video file with OpenCV.
cv::VideoCapture videoSource;
if (!videoSource.open("test.mp4"))
return -1;
// Get frame size from video source.
int width = (int)videoSource.get(cv::CAP_PROP_FRAME_WIDTH);
int height = (int)videoSource.get(cv::CAP_PROP_FRAME_HEIGHT);
// Init frames.
cv::Mat inputFrameBgr(height, width, CV_8UC3);
cv::Mat inputFrameYuv(height, width, CV_8UC3);
cr::video::Frame nv12Frame(width, height, cr::video::Fourcc::NV12);
cr::video::Frame h264Frame(width, height, cr::video::Fourcc::H264);
// Main loop.
while (true)
{
// Capture next video frame.
videoSource >> inputFrameBgr;
if (inputFrameBgr.empty())
{
// Set first video frame position.
videoSource.set(cv::CAP_PROP_POS_FRAMES, 1);
continue;
}
// Convert BGR to YUV.
cvtColor(inputFrameBgr, inputFrameYuv, cv::COLOR_BGR2YUV);
// Convert YUV to NV12 (replacing pixels). You can use something else.
size_t p = height;
nv12Frame.frameId++; // Just to show unique info.
for (size_t i = 0; i < (size_t)height; i = i + 2)
{
for (size_t j = 0; j < (size_t)width; j = j + 2)
{
nv12Frame.data[i * (size_t)width + j] =
inputFrameYuv.data[i * (size_t)width * 3 + j * 3];
nv12Frame.data[i * (size_t)width + j + 1] =
inputFrameYuv.data[i * (size_t)width * 3 + j * 3 + 3];
nv12Frame.data[(i + 1) * (size_t)width + j] =
inputFrameYuv.data[(i + 1) * (size_t)width * 3 + j * 3];
nv12Frame.data[(i + 1) * (size_t)width + j + 1] =
inputFrameYuv.data[(i + 1) * (size_t)width * 3 + j * 3 + 3];
nv12Frame.data[p * width + j] =
inputFrameYuv.data[i * (size_t)width * 3 + j * 3 + 1];
nv12Frame.data[p * width + j + 1] =
inputFrameYuv.data[i * (size_t)width * 3 + j * 3 + 2];
}
++p;
}
// Encode data.
if (!encoder->transcode(nv12Frame, h264Frame))
{
std::cout << "Can't encode frame" << std::endl;
continue;
}
// Show info.
std::cout << "[" << h264Frame.frameId << "] Size " <<
h264Frame.size << " Compression ratio : %" <<
(int)(100.0f * ((float)h264Frame.size / (float)nv12Frame.size)) <<
std::endl;
}
}
