| //MP4Analyze.h
#define uint8_t unsigned char
/******atom tag*******/
uint8_t moov[] = "moov";
uint8_t trak[] = "trak";
uint8_t mdia[] = "mdia";
uint8_t minf[] = "minf";
uint8_t stbl[] = "stbl";
uint8_t stsd[] = "stsd";
uint8_t stsc[] = "stsc";
uint8_t stsz[] = "stsz";
uint8_t stco[] = "stco";
uint8_t ftyp[] = "ftyp";
uint8_t mdat[] = "mdat";
typedef struct Atom
{
unsigned int size;
uint8_t tag[4];
int ver_flag;
unsigned int num_of_entries;
unsigned int pos;
uint8_t *data;
} Atom;
/****audio format****/
uint8_t kmp3[] = {0x6D,0x73,0x00,0x55};
uint8_t fmp3[] = ".mp3";
uint8_t raw[] = "raw ";
uint8_t wave[] = "wave";
uint8_t mp4a[] = "mp4a";
uint8_t enca[] = "enca";//encrypted to ISO/IEC 14496-12 or 3GPP standards
uint8_t smar[] = "smar";//encoded to 3GPP GSM 6.10 AMR narrowband standards
uint8_t sawb[] = "sawb";//encoded to 3GPP GSM 6.10 AMR wideband standards
uint8_t m4ds[] = "m4ds";//encoded to ISO/IEC 14496-10 AVC standards
uint8_t esds[] = "esds";
uint8_t fram[] = "fram";
/*** We may not need these ***/
#define MKTAG(a,b,c,d) (a | (b << 8) | (c << 16) | (d << 24))
typedef struct AVCodecTag {
int id;
unsigned int tag;
} AVCodecTag;
typedef struct stsdtable
{
unsigned int size;
char format[4];
int res1;
int ref;
short version;
short pad1;
int pad2;
short channels;
short bitspersample;
short compress_id;
short res2;
short samplerate1;
short samplerate2;
//{if(version==1)
int sampleperpacket;
int bytesperpacket;
int bytesperframe;
int bytespersample;
//}
} stsdtable;
/***** result is stored here ******/
typedef struct sampletable
{
unsigned int size;
unsigned int id_of_sd;
} sampletable;
//MP4Analyze.cpp
#include "MP4Analyze.h"
#include <vector>
#include <map>
#include <iostream>
#include <string>
#ifdef WIN32
#include <winsock2.h>
#pragma comment(lib, "Ws2_32.lib")
#pragma warning (disable:4786)
#endif
#ifdef __GNUG__
#include <netinet/in.h>
#endif
using namespace std;
/**
*** mp4存在宽度为8字节的wide atom tag，需要注意，这里暂未考虑
**/
/*
* check if a mov/mp4/3gp type
*/
int check_format(uint8_t *data, int size)
{
if(strncmp((char*)moov,(char*)(data+4),4)==0 ||
strncmp((char*)ftyp,(char*)(data+4),4)==0 ||strncmp((char*)mdat,(char*)(data+4),4)==0 )
return 0;
return -1;
}
unsigned int get_size(const uint8_t *data,int size)
{
unsigned int tmp = 0;
for(int i=0; i<size; ++i)
{
tmp <<= 8;
tmp += *data++;
}
return tmp;
}
/* if found,return the offset from the data[0]*/
int seek_tag(uint8_t tag[],uint8_t *data, unsigned int size1,uint8_t **pos,unsigned int *size2)
{
if(data == NULL || size1 == 0)
return -1;
unsigned int tag_size = get_size(data,4);
if(tag_size >size1 + 8)
return -1;
unsigned int tmp = 0;
while(strncmp((char*)data+4,(char*)tag,4) != 0)
{
// printf("%s/n",data+4);
if(tag_size==0)
return -1;
if(tag_size < size1 + 8)
{
data += tag_size;
tmp += tag_size;
}
else
return -1;
tag_size = get_size(data,4);
}
printf("find :%c%c%c%c/n",tag[0],tag[1],tag[2],tag[3]);
if(tmp + tag_size > size1 )
printf("warning: the atom may be not complete!/n");
*pos = data+8;
*size2 = tag_size -8;
return tmp;
}
/*** elementary stream descriptor analyse ***/
/*
unsigned int codec_get_tag(const AVCodecTag *tags, int id)
{
while (tags->id != CODEC_ID_NONE) {
if (tags->id == id)
return tags->tag;
tags++;
}
return 0;
}
/* may not need analyse
int esds_analyze(uint8_t *data, unsigned int size)
{
return 0;
}
*/
/*version == 2 ??? reffer to ffmpeg source mov.c line 943
if (format == MKTAG('l','p','c','m'))
st->codec->codec_id = mov_get_lpcm_codec_id(st->codec->bits_per_coded_sample, flags);
*/
vector<stsdtable>& get_audio_info(uint8_t *data, unsigned int size, vector<stsdtable>& stable)//stsd
{
uint8_t * datapos = data;
Atom *stsd_audio =(Atom *)data;
int tmp_size = 16;
printf("size : %u/n",ntohl(stsd_audio->size));
printf("num_entr: %u/n",ntohl(stsd_audio->num_of_entries));
for(int i=0; i < ntohl(stsd_audio->num_of_entries); ++i)
{
if(tmp_size > size)//注意
return stable;
datapos += tmp_size;
stsdtable * audio_entry = (stsdtable *)(datapos);
stable.push_back(*audio_entry);//这里存入的是网络序的数据，使用时需进行转换
tmp_size += ntohl(audio_entry->size);
/***************/
printf("--tablesize: %d/n",ntohl(audio_entry->size));
printf("--format : %s/n",audio_entry->format);
printf("--version : %d/n",ntohs(audio_entry->version));
printf("--channels: %d/n",ntohs(audio_entry->channels));
printf("--bitpersam: %d/n",ntohs(audio_entry->bitspersample));
printf("--IDcompress: %d/n",ntohs(audio_entry->compress_id));
printf("--samplerate: %d.%d/n",ntohs(audio_entry->samplerate1),ntohs(audio_entry->samplerate2));
/**************/
tmp_size = sizeof(stsdtable);
if(ntohs(audio_entry->version)==0)
{
tmp_size -= 16;
}
datapos += tmp_size;
//if(ntohs(audio_entry->compress_id)==-2)//此处尚需考证
if(ntohl(audio_entry->size) > sizeof(stsdtable))
{
printf("----atom size:%d/n",get_size(datapos,4));
printf("----atom name:%c%c%c%c/n",datapos[4],datapos[5],datapos[6],datapos[7]);
if(strncmp((char*)datapos,(char*)esds,4)==0)
{
//handle esds
}
}
}
return stable;
}
map<unsigned int,sampletable> & get_packet_offset(uint8_t *STBL[], map<unsigned int,sampletable>& table)
{
//table.insert(pair<long,sampletable>(1,sample));
unsigned int num_sam_to_chunk = get_size(STBL[0]-4,4);//stsc
unsigned int num_sample = get_size(STBL[1]-4,4);//stsz
unsigned int num_chunk = get_size(STBL[2]-4,4);//stco
unsigned int chunk_index = 0;
unsigned int next_chunk_index = 0;
uint8_t *cur_sam_to_chunk = STBL[0];
uint8_t *cur_sam_size = STBL[1];
uint8_t *cur_chunk_offset = STBL[2];
sampletable sample;
printf("number of stsc entries:%d /nnumber of sample size:%d /nnumber of chunk offset:%d/n",num_sam_to_chunk,num_sample,num_chunk);
for(unsigned int i = 0; i < num_sam_to_chunk; ++i)//对所有的entries
{
chunk_index = get_size(cur_sam_to_chunk,4);
next_chunk_index = get_size(cur_sam_to_chunk+12,4);
sample.id_of_sd = get_size(cur_sam_to_chunk+8,4);
if(i == num_sam_to_chunk -1)//最后一个
{
next_chunk_index = num_chunk+1;
}
printf("chunk_index:(%d---%d)/n",chunk_index,next_chunk_index);
for(unsigned int k=chunk_index; k < next_chunk_index; ++k)//当前chunk序号到下一个chunk序号之间的chunk
{//处理所有重复的chunk
printf("chunk_index:%d sample num:%d/n",chunk_index,get_size(cur_sam_to_chunk+4,4));
unsigned int offset = get_size(cur_chunk_offset+(chunk_index-1)*4,4);
for(unsigned int j=0; j < get_size(cur_sam_to_chunk+4,4); ++j)//chunk内地sample数目
{//处理该chunk中的sample
sample.size = get_size(cur_sam_size,4);
printf("--sample offset:%d %x size:%d/n",offset,offset,sample.size);
table.insert(pair<unsigned int,sampletable>(offset,sample));
offset = offset + sample.size;
cur_sam_size += 4;
}
system("pause");
chunk_index++;
}
cur_sam_to_chunk += 12;
}
return table;
}
int seek_audio_atom( uint8_t *data1, unsigned int size1)
{
uint8_t tag[] = "mdiaminfsmhd";
uint8_t *datapos;
unsigned int tag_size;
uint8_t *data;
unsigned int size;
int offset_of_atom = 0;
if((offset_of_atom = seek_tag(moov, data1, size1, &data, &size)) == -1)
return -1;
if(offset_of_atom + size >size1)
{ //some handles
printf("moov atom is not complete,need more data");
}
data1 = data;
size1 = size;
uint8_t *nexttrak = data;
unsigned int traksize = size;
int i=0;
while(1)
{
printf("-----/n");
if(seek_tag(trak, nexttrak, traksize, &datapos, &tag_size) != -1)
{
nexttrak = datapos + tag_size;
if(size1 < (nexttrak - data1))
return -1;
traksize = size1 - (nexttrak - data1);
data = datapos;
size = tag_size;
}
else
{
return -1;
}
i=0;
while(i<3)
{
if(seek_tag(tag+i*4, data, size, &datapos, &tag_size) != -1)
{
if(i==2)
break;
data = datapos;
size = tag_size;
++i;
}
else
{
break;
}
}
if(strncmp("smhd",(char*)(datapos-4),4) == 0)
{
if(seek_tag(stbl, data, size, &datapos, &tag_size)!= -1)
{
printf("—find audio stbl—!/n");
data = datapos;
size = tag_size;
if(seek_tag(stsd, data, size, &datapos, &tag_size) != -1)
{
vector<stsdtable> stable; //音频信息
get_audio_info(datapos-8, tag_size,stable);
}
uint8_t *STBL[3] ={NULL,NULL,NULL};//
uint8_t *datapos1;
unsigned int tag_size1;//
if(seek_tag(stsc, data, size, &datapos1, &tag_size1) != -1)
{
STBL[0] = datapos1 + 8;
}
uint8_t *datapos2;
unsigned int tag_size2;
if(seek_tag(stsz, data, size, &datapos2, &tag_size2) != -1)
{
STBL[1] = datapos2 + 12;
}
uint8_t *datapos3;
unsigned int tag_size3;
if(seek_tag(stco, data, size, &datapos3, &tag_size3) != -1)
{
STBL[2] = datapos3 + 8;
}
if(STBL[0] && STBL[1] && STBL[2] )
{
map<unsigned int,sampletable> postable;//音频帧信息
get_packet_offset(STBL,postable);
}
}
return 0;
}
}
return -1;
}
int main(char arg, char *argv[])
{
FILE *mp4;
cout<<"please input the file name :"<<endl;
string filename;
cin>>filename;
mp4 = fopen(filename.c_str(),"rb");
uint8_t buffer[300000];
fread(buffer,1,300000,mp4);
seek_audio_atom((uint8_t*)buffer,300000);
fclose(mp4);
return 0;
}
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