本文共 1156 字,大约阅读时间需要 3 分钟。
#include结果为:using namespace std;int main(){ int offset; int fromWhere; // 2表示文件结尾 FILE *fp = fopen("myData.txt", "w"); fprintf(fp, "123456"); fclose(fp); fp = fopen("myData.txt", "r"); offset = 0; fromWhere = 2; fseek(fp, offset, fromWhere); cout << ftell(fp) << endl; fclose(fp); cout << "*********************" << endl; int a[10]; memset(a, 0, sizeof(a)); fp = fopen("yourData", "wb"); fwrite(a, sizeof(a), 1, fp); fclose(fp); fp = fopen("yourData", "rb"); fseek(fp, offset, fromWhere); cout << ftell(fp) << endl; fclose(fp); return 0;}
6
********************* 40
在视频中,经常要求视频的帧数,现有foreman_qcif.yuv文件,帧数为300,且看下面程序:(x264中就是这么求的)
#include// yuv文件结构体typedef struct yuvFile{ FILE *fp; int width; int height;}YUVFILE;// 获取yuv文件的帧数int getFrameTotalYuv(YUVFILE file){ int frameTotal; int size; if( !fseek( file.fp, 0, SEEK_END ) ) { size = ftell( file.fp ); frameTotal = size/( file.width * file.height * 3 / 2 ); // yuv420 } return frameTotal;}int main(){ YUVFILE file; file.fp = fopen("foreman_qcif.yuv", "rb"); file.width = 176; file.height = 144; printf("%d\n", getFrameTotalYuv(file)); return 0;}
结果为:300
转载地址:http://xnzti.baihongyu.com/