一.视频中添加 LOGO 图像大体流程

        首先初始化VI,VENC模块并使能，然后创建两个线程：1.把LOGO灰度化，然后获取VI原始数据，其次把VI数据Mat化并创建一个感兴趣区域，最后把LOGO放感兴趣区域里并把数据发送给VENC。2.专门获取VENC数据，并存储数据到文件里。

二.代码具体实现

// Copyright 2020 Fuzhou Rockchip Electronics Co., Ltd. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.

#include <assert.h>
//#include <bits/types/FILE.h>
#include <fcntl.h>
#include <getopt.h>
#include <opencv2/imgproc.hpp>
#include <pthread.h>
#include <signal.h>
#include <stdbool.h>
#include <stdio.h>
#include <stdlib.h>
#include <time.h>
#include <unistd.h>

// #include "common/sample_common.h"
#include "rkmedia_api.h"

#include <opencv2/core.hpp>
// #include <opencv2/imgoroc.hpp>
#include <opencv2/highgui.hpp>
#include <opencv2/opencv.hpp>

using namespace cv;
using namespace std;


#define CAMERA_PATH "rkispp_scale0"
#define CAMERA_ID 0
#define CAMERA_CHN 0
#define VENC_CHN 0
#define WIDTH 1920
#define HEIGHT 1080

//opencv的Logo处理VI线程
void *opencv_vi_logo_handle_thread(void *args)
{
  pthread_detach(pthread_self());

  MEDIA_BUFFER mb = NULL;
  Mat logo_img = imread("zjl.jpg");//读取LOGO图片编码Mat矩阵
  cvtColor(logo_img, logo_img, COLOR_RGB2GRAY); //cvtColor把彩色图像转换成灰度图

  while (1)
  {
    mb = RK_MPI_SYS_GetMediaBuffer(RK_ID_VI, CAMERA_CHN, -1);//获取VI模块的数据
    if (!mb)
    {
      printf("Get vi break....\n");
      break;
    }

    printf("Get vi success...\n");

    Mat rv1126_img_mat = Mat(HEIGHT, WIDTH, CV_8UC1, RK_MPI_MB_GetPtr(mb));//把VI数据转换成Mat矩阵
    Mat rv1126_img_mat_roi = rv1126_img_mat(Rect(100, 100, logo_img.cols, logo_img.rows));//在Mat矩阵里面获取感兴趣区域
    logo_img.copyTo(rv1126_img_mat_roi);//把Logo的矩阵拷贝到可感兴趣区域
    RK_MPI_SYS_SendMediaBuffer(RK_ID_VENC, VENC_CHN, mb);//把处理后的VI数据传输给VENC编码器
    RK_MPI_MB_ReleaseBuffer(mb);//释放资源
  }

  return NULL;
}


//专门获取上面处理好的数据并保存到文件里
void *get_venc_stream_thread(void *args)
{
  pthread_detach(pthread_self());
  MEDIA_BUFFER mb = NULL;
  FILE * h264_opencv_logo_file = fopen("test_opencv_logo.h264", "w+"); //

  while (1)
  {
    mb = RK_MPI_SYS_GetMediaBuffer(RK_ID_VENC, VENC_CHN, -1);//获取VENC编码器数据
    if(!mb)
    {
       printf("Get venc break.....\n");
       break;
    }

    fwrite(RK_MPI_MB_GetPtr(mb), RK_MPI_MB_GetSize(mb), 1 , h264_opencv_logo_file);//保存数据
    RK_MPI_MB_ReleaseBuffer(mb);//释放资源
  }

  return NULL;
}

int main()
{
  int ret;
  VI_CHN_ATTR_S vi_chn_attr;
  vi_chn_attr.pcVideoNode = CAMERA_PATH;        // Path
  vi_chn_attr.u32Width = WIDTH;                 // Width
  vi_chn_attr.u32Height = HEIGHT;               // Height
  vi_chn_attr.enPixFmt = IMAGE_TYPE_NV12;       // ImageType
  vi_chn_attr.enBufType = VI_CHN_BUF_TYPE_MMAP; // BufType
  vi_chn_attr.u32BufCnt = 3;                    // Cnt
  vi_chn_attr.enWorkMode = VI_WORK_MODE_NORMAL; // Mode
  ret = RK_MPI_VI_SetChnAttr(CAMERA_ID, CAMERA_CHN, &vi_chn_attr);
  if (ret)
  {
    printf("Vi Set Attr Failed.....\n");
    return 0;
  }
  else
  {
    printf("Vi Set Attr Success.....\n");
  }

  ret = RK_MPI_VI_EnableChn(CAMERA_ID, CAMERA_CHN);
  if (ret)
  {
    printf("Vi Enable Attr Failed.....\n");
    return 0;
  }
  else
  {
    printf("Vi Enable Attr Success.....\n");
  }

  VENC_CHN_ATTR_S venc_chn_attr;
  memset(&venc_chn_attr, 0, sizeof(VENC_CHN_ATTR_S));
  venc_chn_attr.stVencAttr.u32PicWidth = WIDTH;
  venc_chn_attr.stVencAttr.u32PicHeight = HEIGHT;
  venc_chn_attr.stVencAttr.u32VirWidth = WIDTH;
  venc_chn_attr.stVencAttr.u32VirHeight = HEIGHT;
  venc_chn_attr.stVencAttr.imageType = IMAGE_TYPE_NV12;
  venc_chn_attr.stVencAttr.enType = RK_CODEC_TYPE_H264;
  venc_chn_attr.stVencAttr.u32Profile = 66;
  venc_chn_attr.stRcAttr.enRcMode = VENC_RC_MODE_H264CBR;
  venc_chn_attr.stRcAttr.stH264Cbr.u32Gop = 25;
  venc_chn_attr.stRcAttr.stH264Cbr.u32BitRate = WIDTH * HEIGHT * 3;
  venc_chn_attr.stRcAttr.stH264Cbr.fr32DstFrameRateDen = 1;
  venc_chn_attr.stRcAttr.stH264Cbr.fr32DstFrameRateNum = 25;
  venc_chn_attr.stRcAttr.stH264Cbr.u32SrcFrameRateDen = 1;
  venc_chn_attr.stRcAttr.stH264Cbr.u32SrcFrameRateNum = 25;
  ret = RK_MPI_VENC_CreateChn(VENC_CHN, &venc_chn_attr);  
  if (ret)
  {
    printf("ERROR: Create venc failed!\n");
    exit(0);
  }

  ret = RK_MPI_VI_StartStream(CAMERA_ID, CAMERA_CHN);
  if (ret)
  {
    printf("start vi failed....\n");
  }
  else
  {
    printf("start vi success....\n");
  }

  pthread_t pid1, pid2;
  pthread_create(&pid1, NULL, opencv_vi_logo_handle_thread, NULL);
  pthread_create(&pid2, NULL, get_venc_stream_thread, NULL);

  while (1)
  {
    sleep(2);
  }

  RK_MPI_VENC_DestroyChn(VENC_CHN);
  RK_MPI_VI_DisableChn(CAMERA_ID, CAMERA_CHN);

  return 0;
}

 三.效果图