AVDataProcess/h264_parser.cpp

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#include <stdio.h>
#include <stdlib.h>
#include <string.h>
//0x00000001或0x000001是一个nalu的起始标志遇到下一个此标志时为该nalu的结尾。
//起始标志的后面第一个字节type里包含有nalu的类型type & 0x1F即为该nalu的类型nalu_type
typedef enum {
NALU_TYPE_SLICE = 1, //非IDR图像中不采用数据划分的片段为P或B帧
NALU_TYPE_DPA = 2, //非IDR图像中A类数据划分片段
NALU_TYPE_DPB = 3, //非IDR图像中B类数据划分片段
NALU_TYPE_DPC = 4, //非IDR图像中C类数据划分片段
NALU_TYPE_IDR = 5, //IDR图像的片段关键帧I帧
NALU_TYPE_SEI = 6, //补充增强信息
NALU_TYPE_SPS = 7, //序列参数集Sequence Parameter Set
NALU_TYPE_PPS = 8, //图像参数集PPSPicture Parameter Set
NALU_TYPE_AUD = 9, //分割符
NALU_TYPE_EOSEQ = 10, //序列结束符
NALU_TYPE_EOSTREAM = 11, //流结束符
NALU_TYPE_FILL = 12, //填充数据
}NaluType;
//类型说明参考http://www.cnblogs.com/lidabo/p/4481601.html
typedef enum {
NALU_PRIORITY_DISPOSABLE = 0,
NALU_PRIORITY_LOW = 1,
NALU_PRIORITY_HIGH = 2,
NALU_PRIORITY_HIGHEST = 3,
}NaluPriority;
typedef struct
{
int startcode_len; //! 起始码长度3个字节或4个字节
unsigned len; //! NALU长度不包括起始码长度
unsigned max_size; //! Nal Unit Buffer size
int forbidden_bit; //! should be always FALSE
//! 禁止位网络发现NAL单元有比特错误时可设置该比特为1以便接收方丢掉该单元。
int nal_reference_idc; //! 表示NAL的优先级。03取值越大表示当前NAL越重要需要优先受到保护。
//! 如果当前NAL是属于参考帧的片或是序列参数集或是图像参数集这些重要的单位时
//! 本句法元素必需大于0。
int nalu_type; //! NALU类型
char *buf; //! contains the first byte followed by the EBSP
} NALU_t;
//如果NALU对应的Slice为一帧的开始就用0x00000001否则就用0x000001。
int findStartCode2(unsigned char *buf)
{
if ( buf[0]!=0 || buf[1]!=0 || buf[2]!=1 ) {
return 0; //0x000001
} else {
return 1;
}
}
int findStartCode3(unsigned char *buf)
{
if ( buf[0]!=0 || buf[1]!=0 || buf[2]!=0 || buf[3]!=1 ) {
return 0; //0x00000001
} else {
return 1;
}
}
//如果NALU对应的Slice为一帧的开始就用0x00000001(即3个字节长度)否则就用0x000001(即4个字节长度)。
int findStartCode(const unsigned char *buf)
{
if (strlen((const char*)buf) >= 3) {
if ( buf[0]==0 && buf[1]==0 && buf[2]==1) {
return 3;
}
}
if (strlen((const char*)buf) >= 4) {
if ( buf[0]==0 && buf[1]==0 && buf[2]==0 && buf[3]==1) {
return 4;
}
}
return 0;
}
int getNalu(NALU_t *nalu, FILE *fp)
{
if (nalu == NULL) {
return -1;
}
unsigned char *buf = (unsigned char *)malloc(nalu->max_size);
if (buf == NULL) {
return 0;
} else {
memset(buf, 0, nalu->max_size);
}
nalu->startcode_len = 3;
//读取前三个字节以判断NALU的起始标志
if (3 != fread(buf, 1, 3, fp)) {
free(buf);
return 0;
}
//获取起始码长度
int info3 = 0;
int pos = 0;
int info2 = findStartCode2(buf);
if (info2 != 1) {
if (1 != fread(buf+3, 1, 1, fp)) {
free(buf);
return 0;
}
info3 = findStartCode3(buf);
if (info3 != 1) {
free(buf);
return -1;
} else {
pos = 4;
nalu->startcode_len = 4;
}
} else {
pos = 3;
nalu->startcode_len = 3;
}
while (1) {
if (feof(fp)) { //文件结束
nalu->len = (pos-1) - nalu->startcode_len;
memcpy(nalu->buf, &buf[nalu->startcode_len], nalu->len);
nalu->forbidden_bit = nalu->buf[0] & 0x80; //1 bit
nalu->nal_reference_idc = nalu->buf[0] & 0x60; //2 bit
nalu->nalu_type = nalu->buf[0] & 0x1f; //5 bit
free(buf);
return pos-1;
}
buf[pos++] = fgetc(fp);
info3 = findStartCode3(&buf[pos-4]);
if (info3 != 1) {
info2 = findStartCode2(&buf[pos-3]);
}
if (info2==1 || info3==1) {
break;
}
}
int rewind = (info3==1) ? -4 : -3;
if (0 != fseek(fp, rewind, SEEK_CUR)) {
free(buf);
}
nalu->len = (pos+rewind) - nalu->startcode_len;
memcpy(nalu->buf, &buf[nalu->startcode_len], nalu->len);
nalu->forbidden_bit = nalu->buf[0] & 0x80; //1 bit
nalu->nal_reference_idc = nalu->buf[0] & 0x60; //2 bit
nalu->nalu_type = nalu->buf[0] & 0x1f; //5 bit
free(buf);
return pos+rewind;
}
int h264_parser(char *file)
{
FILE *h264BitStream = fopen(file, "rb+");
if (h264BitStream == NULL) {
return 0;
}
NALU_t *nalu = (NALU_t *)malloc(sizeof(NALU_t));
if (nalu == NULL) {
return 0;
} else {
memset(nalu, 0, sizeof(NALU_t));
}
nalu->max_size = 100000;
nalu->buf = (char *)malloc(100000);
if (nalu->buf == NULL) {
return 0;
} else {
memset(nalu->buf, 0, 100000);
}
int data_offset=0;
int nal_num=0;
printf("-----+-------- NALU Table ------+---------+\n");
printf(" NUM | POS | IDC | TYPE | LEN |\n");
printf("-----+---------+--------+-------+---------+\n");
while(!feof(h264BitStream)) {
int dataLen = getNalu(nalu, h264BitStream);
char sType[20] = {0};
switch(nalu->nalu_type) {
case NALU_TYPE_SLICE: sprintf(sType, "SLICE"); break;
case NALU_TYPE_DPA: sprintf(sType, "DPA"); break;
case NALU_TYPE_DPB: sprintf(sType, "DPB"); break;
case NALU_TYPE_DPC: sprintf(sType, "DPC"); break;
case NALU_TYPE_IDR: sprintf(sType, "IDR"); break;
case NALU_TYPE_SEI: sprintf(sType, "SEI"); break;
case NALU_TYPE_SPS: sprintf(sType, "SPS"); break;
case NALU_TYPE_PPS: sprintf(sType, "PPS"); break;
case NALU_TYPE_AUD: sprintf(sType, "AUD"); break;
case NALU_TYPE_EOSEQ: sprintf(sType, "EOSEQ"); break;
case NALU_TYPE_EOSTREAM: sprintf(sType, "EOSTREAM"); break;
case NALU_TYPE_FILL: sprintf(sType, "FILL"); break;
}
char idc_str[20] = {0};
switch(nalu->nal_reference_idc >> 5) {
case NALU_PRIORITY_DISPOSABLE:sprintf(idc_str,"DISPOS");break;
case NALU_PRIORITY_LOW:sprintf(idc_str,"LOW");break;
case NALU_PRIORITY_HIGH:sprintf(idc_str,"HIGH");break;
case NALU_PRIORITY_HIGHEST:sprintf(idc_str,"HIGHEST");break;
}
FILE *out = stdout;
fprintf(out,"%5d| %8d| %7s| %6s| %8d|\n",nal_num,data_offset,idc_str,sType,nalu->len);
nal_num++;
data_offset = data_offset + dataLen;
}
if (nalu) {
if (nalu->buf) {
free(nalu->buf);
nalu->buf = NULL;
}
free(nalu);
}
return 0;
}
int main(int argc, char *argv[])
{
if (argc == 2) {
h264_parser(argv[1]);
}
return 0;
}