#include <stdio.h>
#include <malloc.h>
#include <string.h>#if _WIN32
#define __func__ __FUNCTION__
#endif#define SWAP_EDIAN_U32(X) (((0x000000ff&(X))<<24)|((0x0000ff00&(X))<<8)|((0x00ff0000&(X))>>8)|((0xff000000&(X))>>24))typedef unsigned long long int VSize_t ;#pragma pack(1)
typedef struct{unsigned int len;char name[4];unsigned int offset;
}MP4Box;
#pragma pack()int findBox(const char *vidname,MP4Box *box,int offset)
{FILE *vfp=fopen(vidname,"rb");if(NULL==vfp){printf("[%s-%d]:Open %s failed !\n",__func__,__LINE__,vidname);return -1;}fseek(vfp,0,SEEK_END);VSize_t flen=ftell(vfp);fseek(vfp,offset,SEEK_SET);flen-=offset;VSize_t rlen=0;int ret=0;while(rlen<flen){MP4Box boxtmp;if(8!=fread((unsigned char *)&boxtmp,1,8,vfp)){printf("[%s-%d]:Read %s error !\n",__func__,__LINE__,vidname);ret=-1;break;}        char srcname[5];char dstname[5];    memcpy(srcname,boxtmp.name,4);srcname[4]=0;memcpy(dstname,box->name,4);dstname[4]=0;//printf("rlen=%x\n",rlen);//int t=0;//unsigned char *ppp=(unsigned char *)&boxtmp;//for(t=0;t<8;t++){//    printf("%02x ",ppp[t]);//}//printf("\n");VSize_t boxLen=SWAP_EDIAN_U32(boxtmp.len);if(boxLen<8){printf("[%s-%d]:%s file damage\n",__func__,__LINE__,vidname);ret=-1;break;}if(0==strcmp(srcname,dstname)){memcpy((unsigned char *)box,(unsigned char *)&boxtmp,8);if(rlen+boxLen>flen){ret=0;break;}box->offset=ftell(vfp)-8;ret=1;break;}else{if(rlen+boxLen>flen){printf("[%s-%d]:Box length beyond file !\n",__func__,__LINE__);ret=0;break;}fseek(vfp,boxLen-8,SEEK_CUR);rlen+=boxLen;}}fclose(vfp);return ret;
}void changeStco(unsigned char *buf,int len,int chunkDeta)
{int i=0;unsigned int *pchunkOffset=0;for(i=16;i<len;i+=4){pchunkOffset=(unsigned int *)(buf+i);*pchunkOffset=SWAP_EDIAN_U32(SWAP_EDIAN_U32(*pchunkOffset)+chunkDeta);}
}int main(int argc,char **argv)
{if(3!=argc){printf("Usage:\n");printf("mp4ThumbPick test.mp4 out.mp4");return -1;}MP4Box matBox,moovBox,stcoBox;{char dstName[4]={'m','d','a','t'};memcpy(matBox.name,dstName,4);if(findBox(argv[1],&matBox,0)>0){printf("mdat offset:0x%08x\n",matBox.offset);    }}{char dstName[4]={'m','o','o','v'};memcpy(moovBox.name,dstName,4);if(findBox(argv[1],&moovBox,0)>0){printf("moov offset:0x%08x\n",moovBox.offset);    }}{MP4Box box;char dstName[4]={'t','r','a','k'};memcpy(box.name,dstName,4);if(findBox(argv[1],&box,moovBox.offset+8)<=0){printf("trak box not founc\n");return -1;}        char dstName1[4]={'m','d','i','a'};memcpy(box.name,dstName1,4);if(findBox(argv[1],&box,box.offset+8)<=0){printf("mdia box not founc\n");return -1;}char dstName2[4]={'m','i','n','f'};memcpy(box.name,dstName2,4);if(findBox(argv[1],&box,box.offset+8)<=0){printf("minf box not founc\n");return -1;}char dstName3[4]={'s','t','b','l'};memcpy(box.name,dstName3,4);if(findBox(argv[1],&box,box.offset+8)<=0){printf("stbl box not founc\n");return -1;}char dstName4[4]={'s','t','c','o'};memcpy(box.name,dstName4,4);if(findBox(argv[1],&box,box.offset+8)<=0){printf("stco box not founc\n");return -1;}stcoBox=box;}int matLen=SWAP_EDIAN_U32(matBox.len);int moovLen=SWAP_EDIAN_U32(moovBox.len);int stcoLen=SWAP_EDIAN_U32(stcoBox.len);printf("matBox.offset:%d,matBox.len=%d\n",matBox.offset,matLen);printf("moovBox.offset:%d,moovBox.len=%d\n",moovBox.offset,moovLen);printf("stcoBox.offset:%d,stcoBox.len=%d\n",stcoBox.offset,stcoLen);FILE *infp=fopen(argv[1],"rb");FILE *outfp=fopen(argv[2],"wb");if(NULL==infp||NULL==outfp){printf("Open %s/%s error!\n",argv[1],argv[2]);}fseek(infp,0,SEEK_END);int flen=ftell(infp);fseek(infp,0,SEEK_SET);unsigned char *buf=(unsigned char *)malloc(matBox.offset);fread(buf,1,matBox.offset,infp);fwrite(buf,1,matBox.offset,outfp);free(buf);//save moovbuf=(unsigned char *)malloc(moovLen);fseek(infp,moovBox.offset,SEEK_SET);fread(buf,1,moovLen,infp);changeStco(buf+stcoBox.offset-moovBox.offset,stcoLen,moovLen);fwrite(buf,1,moovLen,outfp);free(buf);//save mdatint rrlen=0,rlen=0;buf=(unsigned char *)malloc(1024);fseek(infp,matBox.offset,SEEK_SET);while(rlen<matLen){if(rlen+1024<=matLen){rrlen=fread(buf,1,1024,infp);fwrite(buf,1,1024,outfp);rlen+=rrlen;}else{rrlen=fread(buf,1,matLen-rlen,infp);fwrite(buf,1,matLen-rlen,outfp);break;}}free(buf);//after moovif(moovBox.offset+moovLen<flen){int sparelen=flen-(moovBox.offset+moovLen);buf=(unsigned char *)malloc(sparelen);fseek(infp,moovBox.offset+moovLen,SEEK_SET);fread(buf,1,sparelen,infp);fwrite(buf,1,sparelen,outfp);free(buf);}fclose(infp);fclose(outfp);return 0;
}