11、FFMPEG学习笔记记录之视频格式转换

基本思想：记录学习夏曹俊ffmpeg基本函数使用,window11+clion_mingw+ffmpeg库，基本函数使用和格式转换

一、学习大佬的如何使用av_frame_alloc()

cmakelists.txt

cmake_minimum_required(VERSION 3.16)
project(window11)
set(CMAKE_CXX_STANDARD 11)

include_directories(${CMAKE_SOURCE_DIR}/include)

set(OpenCV_DIR "D:\\Opencv455\\buildMinGW")#改为mingw-bulid的位置
set(CMAKE_MODULE_PATH ${CMAKE_MODULE_PATH} "${CMAKE_SOURCE_DIR}/cmake/")

find_package(OpenCV REQUIRED)
set(OpenCV_LIBS opencv_core opencv_imgproc opencv_highgui opencv_imgcodecs)

add_library(libavformat STATIC IMPORTED)
set_target_properties(libavformat PROPERTIES IMPORTED_LOCATION ${CMAKE_SOURCE_DIR}/lib/libavformat.dll.a)

add_library(libavdevice STATIC IMPORTED)
set_target_properties(libavdevice PROPERTIES IMPORTED_LOCATION ${CMAKE_SOURCE_DIR}/lib/libavdevice.dll.a)


add_library(libavcodec STATIC IMPORTED)
set_target_properties(libavcodec PROPERTIES IMPORTED_LOCATION ${CMAKE_SOURCE_DIR}/lib/libavcodec.dll.a)

add_library(libavfilter STATIC IMPORTED)
set_target_properties(libavfilter PROPERTIES IMPORTED_LOCATION ${CMAKE_SOURCE_DIR}/lib/libavfilter.dll.a)

add_library(libavutil STATIC IMPORTED)
set_target_properties(libavutil PROPERTIES IMPORTED_LOCATION ${CMAKE_SOURCE_DIR}/lib/libavutil.dll.a)

add_library(libswresample STATIC IMPORTED)
set_target_properties(libswresample PROPERTIES IMPORTED_LOCATION ${CMAKE_SOURCE_DIR}/lib/libswresample.dll.a)
add_library(libswscale STATIC IMPORTED)
set_target_properties(libswscale PROPERTIES IMPORTED_LOCATION ${CMAKE_SOURCE_DIR}/lib/libswscale.dll.a)
add_executable(window11 main.cpp )

target_link_libraries(window11 ${OpenCV_LIBS}
        libavformat
        libavdevice
        libavcodec
        libavfilter
        libavutil
        libswresample
        libswscale
        )

main.cpp

#include <iostream>
#include <vector>
#include <opencv2/highgui.hpp>
#include <opencv2/video.hpp>
#include <opencv2/opencv.hpp>
extern "C"
{
#include <libavformat/avformat.h>
#include <libavcodec/avcodec.h>
#include <libavutil/imgutils.h>
#include <libswscale/swscale.h>
}
using namespace std;
using namespace cv;

int main() {

  std::cout<<"first ffmpeg"<<std::endl;
 // std::cout<<avcodec_configuration()<<std::endl;

  auto frame1=av_frame_alloc();
    frame1->width=400;
    frame1->height=300;
    frame1->format=AV_PIX_FMT_ARGB;
  int re=av_frame_get_buffer(frame1,0);
  if(re!=0){
      char buff[1024]={0};
      av_strerror(re,buff,sizeof(buff));
      std::cout<<buff<<std::endl;

  }
  std::cout<<"frame ->line="<<frame1->linesize[0]<<std::endl;
  av_frame_free(&frame1);


    return 0;
}

二、学习大佬如何使用 sws_getCachedContext

cmakelists.txt

cmake_minimum_required(VERSION 3.21)
project(untitled1)
find_package(OpenCV REQUIRED)
set(CMAKE_CXX_STANDARD 14)


add_executable(untitled1 main.cpp)
target_link_libraries(untitled1
        ${OpenCV_LIBS}
        -lavformat -lavcodec -lswscale -lavutil -lz
        )

main.cpp

#include <iostream>
#include <vector>
#include <opencv2/highgui.hpp>
#include <opencv2/video.hpp>
#include <opencv2/opencv.hpp>

extern "C"
{
#include <libavformat/avformat.h>
#include <libavcodec/avcodec.h>
#include <libavutil/imgutils.h>
#include <libswscale/swscale.h>

}

#include <fstream>

using namespace std;
using namespace cv;

int main() {

    std::cout << "first ffmpeg" << std::endl;
    // std::cout<<avcodec_configuration()<<std::endl;

    int width = 1920;
    int height = 1080;
    int rgba_width = 1920;
    int rgba_height = 1080;
    unsigned char *yuv[3] = {0};
    yuv[0] = new unsigned char[width * height];//y
    yuv[1] = new unsigned char[width * height / 4];//y
    yuv[2] = new unsigned char[width * height / 4];//y
    unsigned char *rgba = new unsigned char[rgba_width * rgba_height * 4];
    int rgba_linesize = rgba_width * 4;
    ifstream ifs;
    ifs.open("/home/ubuntu/1920x1080_min.yuv", ios::binary);
    if (!ifs) {
        cerr << "open fail" << endl;
        return -1;
    }
    int yuv_linesize[3] = {width , width /2, width / 2};
    SwsContext *yuv2rgb = NULL;
    while (1) {
        ifs.read((char *) yuv[0], width * height);
        ifs.read((char *) yuv[1], width * height / 4);
        ifs.read((char *) yuv[2], width * height / 4);
        if (ifs.gcount() == 0) break;
        yuv2rgb = sws_getCachedContext(yuv2rgb,
                                       width,
                                       height,
                                       AV_PIX_FMT_YUV420P,
                                       rgba_width,
                                       rgba_height,
                                       AV_PIX_FMT_RGBA,
                                       SWS_BILINEAR,
                                       0, 0, 0
        );
        if (!yuv2rgb) {
            cerr << " paramter error" << endl;
            return -1;
        }
        unsigned char *data[1];
        data[0] = rgba;
        int lines[3] = {rgba_linesize,rgba_linesize,rgba_linesize};
        int re = sws_scale(yuv2rgb, yuv, yuv_linesize, 0, height, data, lines);
        std::cout << re << std::endl;
        cv::Mat RGBAImg;
        RGBAImg.create(height , width, CV_8UC4);  //
        RGBAImg.data = data[0];
        cv::Mat rgbImg = cv::Mat(height, width, CV_8UC3);

        cv::cvtColor(RGBAImg, rgbImg, COLOR_RGBA2BGR);

        if (rgbImg.empty()) {
            printf("rgbImg empty\n");
        }


        cv::imshow("mpp", rgbImg);
        cv::waitKey(1);

    }

    delete yuv[0];
    delete yuv[1];
    delete yuv[2];
    delete rgba;
    return 0;
}