网站建设的专业知识,怎么才能免费建网站,游戏推广平台有哪些,WordPress知更鸟破解版一.AAC音频格式介绍 AAC音频格式#xff1a;Advanced Audio Coding#xff08;高级音频解码#xff09;#xff0c;是一种由MPEG—4标准定义的有损音频压缩格式。音频压缩编码的输出码流#xff0c;以音频帧的形式存在。每个音频帧包含若干个音频采样的压缩数据#xff0…一.AAC音频格式介绍 AAC音频格式Advanced Audio Coding高级音频解码是一种由MPEG—4标准定义的有损音频压缩格式。音频压缩编码的输出码流以音频帧的形式存在。每个音频帧包含若干个音频采样的压缩数据AAC的一个音频帧包含960或1024个样值这些压缩编码后的音频帧称为原始数据块(RawData Block)由于原始数据块以帧的形式存在即简称为原始帧。
二.AAC编码封装格式 原始帧是可变的如果对原始帧进行ADTS的封装得到的原始帧为ADTS帧如果对原始帧进行ADIF封装得到的原始帧为ADIF帧。它们的区别如下
ADIFAudioData Interchange Format音频数据交换格式。这种格式明确解码必须在明确定义的音频数据流的开始处进行常用于磁盘文件中
ADTSAudioData Transport Stream音频数据传输流。这种格式的特点是它一个有同步字的比特流且允许在音频数据流的任意帧解码也就是说它每一帧都有信息头。
三.ADTS帧组成 一个AAC原始数据库长度是可变的对原始帧加上ADTS头进行ADTS封装就形成了ADTS帧。AAC音频的每一帧(ADTS帧)体由ADTS Header和AAC Audio Data(包含1~4个音频原始帧)组成其中ADTS Header占7个字节或9个字节由两部分组成固定头信息(adts_fixed_header)、可变头信息(adts_variable_header)。固定头信息中的数据每一帧都是相同的主要定义了音频的采样率、声道数、帧长度等关键信息这是解码AAC所需关键信息可变头信息则在帧与帧之间可变。
ADTS组成结 ADTS Header结构体
struct AdtsHeader {unsigned int syncword; //12 bit 同步字 1111 1111 1111一个ADTS帧的开始uint8_t id; //1 bit 0代表MPEG-4, 1代表MPEG-2。uint8_t layer; //2 bit 必须为0uint8_t protectionAbsent; //1 bit 1代表没有CRC0代表有CRCuint8_t profile; //1 bit AAC级别MPEG-2 AAC中定义了3种profileMPEG-4 AAC中定义了6种profileuint8_t samplingFreqIndex; //4 bit 采样率uint8_t privateBit; //1bit 编码时设置为0解码时忽略uint8_t channelCfg; //3 bit 声道数量uint8_t originalCopy; //1bit 编码时设置为0解码时忽略uint8_t home; //1 bit 编码时设置为0解码时忽略uint8_t copyrightIdentificationBit; //1 bit 编码时设置为0解码时忽略uint8_t copyrightIdentificationStart; //1 bit 编码时设置为0解码时忽略unsigned int aacFrameLength; //13 bit 一个ADTS帧的长度包括ADTS头和AAC原始流unsigned int adtsBufferFullness; //11 bit 缓冲区充满度0x7FF说明是码率可变的码流不需要此字段。CBR可能需要此字段不同编码器使用情况不同。这个在使用音频编码的时候需要注意。/* number_of_raw_data_blocks_in_frame* 表示ADTS帧中有number_of_raw_data_blocks_in_frame 1个AAC原始帧* 所以说number_of_raw_data_blocks_in_frame 0* 表示说ADTS帧中有一个AAC数据块并不是说没有。(一个AAC原始帧包含一段时间内1024个采样及相关数据)*/uint8_t numberOfRawDataBlockInFrame; //2 bit
};ADTS Header参数含义
syncword占12bits。同步头信息表示一个ADTS帧的开始总是0xFFF。正是因为它的存在才支持解码任意帧ID 占1bit。MPEG的版本0为MPGE-41为MPGE-2Layer 占2bits。总是”00”protection_absent占1bit。0时ADTS Header长度占9字节1时ADTS Header占7字节profile 占2bit。使用哪个级别的AAC值00、01、10分别对应Mainprofile、LC、SSR
sampling_frequency_index占4bits。表示使用的采样率下标通过这个下标在Sampling Frequencies[ ]数组中查找得知采样率的值如0xb对应的采样率为8000Hzchannel_configuration表示声道数如1-单声道2-立体声orininal_copy 1bit 编码时设置为0解码时忽略。
home 1bit 编码时设置为0解码时忽略。
copyrightIdentificationBit 1bit 编码时设置为0解码时忽略。
copyrightIdentificationStart 1bit 编码时设置为0解码时忽略。
aacFrameLength 13bit 一个ADTS帧的⻓度包括ADTS头和AAC原始流。
adtsBufferFullness 11bit 缓冲区充满度0x7FF说明是码率可变的码流不需要此字段。CBR可能需要此字段不同编码器使用情况不同。具体查看附录。
numberOfRawDataBlockInFrame 2bit 表示ADTS帧中有number_of_raw_data_blocks_in_frame 1个AAC原始帧为0表示说ADTS帧中只有一个AAC数据. 四.ACC音频的RTP打包方式 AAC的RTP打包方式就是将ADTS帧取出ADTS头部取出AAC数据每帧数据封装成一个RTP包,需要注意的是并不是将AAC数据直接拷贝到RTP的载荷中。AAC封装成RTP包在RTP载荷中的前四个字节是有特殊含义的然后再是AAC数据如下图所示。
RTP头部1bit1bit1bit1bit ACC DATA
RTP包的结构由RTP头部和RTP载荷组成由上图所知RTP载荷分为4个字节和ACC的数据组成。我们需要注意的RTP封装包并不是将AAC数据直接拷贝到RTP的载荷中AAC封装成RTP包在RTP载荷中的前四个字节是有特殊含义的然后再封装AAC数据。
其中RTP载荷的一个字节为0x00第二个字节为0x10。第三个字节和第四个字节保存AAC Data的大小最多只能保存13bit第三个字节保存数据大小的高八位第四个字节的高5位保存数据大小的低5位。
rtpPacket-payload[0] 0x00;
rtpPacket-payload[1] 0x10;
rtpPacket-payload[2] (frameSize 0x1FE0) 5; //高8位
rtpPacket-payload[3] (frameSize 0x1F) 3; //低5位
RTSP协议推送音频数据代码实现
main.cpp
#include stdio.h
#include stdlib.h
#include stdint.h
#include string.h
#include time.h
#include sys/types.h
#include sys/stat.h
#include fcntl.h
#include WinSock2.h
#include WS2tcpip.h
#include windows.h
#include rtp.h#define SERVER_PORT 8554
#define SERVER_RTP_PORT 55532
#define SERVER_RTCP_PORT 55533
#define BUF_MAX_SIZE (1024*1024)
#define AAC_FILE_NAME ../data/test-long.aacstatic int createTcpSocket() {int sockfd;int on 1;sockfd socket(AF_INET, SOCK_STREAM, 0);if (sockfd 0)return -1;setsockopt(sockfd, SOL_SOCKET, SO_REUSEADDR, (const char*)on, sizeof(on));return sockfd;
}static int createUdpSocket() {int sockfd;int on 1;sockfd socket(AF_INET, SOCK_DGRAM, 0);if (sockfd 0)return -1;setsockopt(sockfd, SOL_SOCKET, SO_REUSEADDR, (const char*)on, sizeof(on));return sockfd;
}static int bindSocketAddr(int sockfd, const char* ip, int port) {struct sockaddr_in addr;addr.sin_family AF_INET;addr.sin_port htons(port);addr.sin_addr.s_addr inet_addr(ip);if (bind(sockfd, (struct sockaddr*)addr, sizeof(struct sockaddr)) 0)return -1;return 0;
}struct AdtsHeader {unsigned int syncword; //12 bit ͬ 1111 1111 1111һADTS֡Ŀʼuint8_t id; //1 bit 0MPEG-4, 1MPEG-2uint8_t layer; //2 bit Ϊ0uint8_t protectionAbsent; //1 bit 1ûCRC0CRCuint8_t profile; //1 bit AACMPEG-2 AACж3profileMPEG-4 AACж6profileuint8_t samplingFreqIndex; //4 bit uint8_t privateBit; //1bit ʱΪ0ʱuint8_t channelCfg; //3 bit uint8_t originalCopy; //1bit ʱΪ0ʱuint8_t home; //1 bit ʱΪ0ʱuint8_t copyrightIdentificationBit; //1 bit ʱΪ0ʱuint8_t copyrightIdentificationStart; //1 bit ʱΪ0ʱunsigned int aacFrameLength; //13 bit һADTS֡ijȰADTSͷAACԭʼunsigned int adtsBufferFullness; //11 bit ȣ0x7FF˵ʿɱҪֶΡCBRҪֶΣͬʹͬʹƵʱҪע⡣/* number_of_raw_data_blocks_in_frame* ʾADTS֡number_of_raw_data_blocks_in_frame 1AACԭʼ֡* ˵number_of_raw_data_blocks_in_frame 0* ʾ˵ADTS֡һAACݿ鲢˵ûС(һAACԭʼ֡һʱ1024)*/uint8_t numberOfRawDataBlockInFrame; //2 bit
};static int parseAdtsHeader(uint8_t* in, struct AdtsHeader* res) {static int frame_number 0;memset(res, 0, sizeof(*res));if ((in[0] 0xFF) ((in[1] 0xF0) 0xF0)){res-id ((uint8_t)in[1] 0x08) 3;//ڶֽ0x08֮õ13λbitӦֵres-layer ((uint8_t)in[1] 0x06) 1;//ڶֽ0x06֮1λõ14,15λbitӦֵres-protectionAbsent (uint8_t)in[1] 0x01;res-profile ((uint8_t)in[2] 0xc0) 6;res-samplingFreqIndex ((uint8_t)in[2] 0x3c) 2;res-privateBit ((uint8_t)in[2] 0x02) 1;res-channelCfg ((((uint8_t)in[2] 0x01) 2) | (((unsigned int)in[3] 0xc0) 6));res-originalCopy ((uint8_t)in[3] 0x20) 5;res-home ((uint8_t)in[3] 0x10) 4;res-copyrightIdentificationBit ((uint8_t)in[3] 0x08) 3;res-copyrightIdentificationStart (uint8_t)in[3] 0x04 2;res-aacFrameLength (((((unsigned int)in[3]) 0x03) 11) |(((unsigned int)in[4] 0xFF) 3) |((unsigned int)in[5] 0xE0) 5);res-adtsBufferFullness (((unsigned int)in[5] 0x1f) 6 |((unsigned int)in[6] 0xfc) 2);res-numberOfRawDataBlockInFrame ((uint8_t)in[6] 0x03);return 0;}else{printf(failed to parse adts header\n);return -1;}
}static int rtpSendAACFrame(int socket, const char* ip, int16_t port,struct RtpPacket* rtpPacket, uint8_t* frame, uint32_t frameSize) {//ĵhttps://blog.csdn.net/yangguoyu8023/article/details/106517251/int ret;rtpPacket-payload[0] 0x00;rtpPacket-payload[1] 0x10;rtpPacket-payload[2] (frameSize 0x1FE0) 5; //8λrtpPacket-payload[3] (frameSize 0x1F) 3; //5λmemcpy(rtpPacket-payload 4, frame, frameSize);ret rtpSendPacketOverUdp(socket, ip, port, rtpPacket, frameSize 4);if (ret 0){printf(failed to send rtp packet\n);return -1;}rtpPacket-rtpHeader.seq;/** Ƶ44100* һAACÿ1024Ϊһ֡* һ 44100 / 1024 43֡* ʱ 44100 / 43 1025* һ֡ʱΪ 1 / 43 23ms*/rtpPacket-rtpHeader.timestamp 1025;return 0;
}static int acceptClient(int sockfd, char* ip, int* port) {int clientfd;socklen_t len 0;struct sockaddr_in addr;memset(addr, 0, sizeof(addr));len sizeof(addr);clientfd accept(sockfd, (struct sockaddr*)addr, len);if (clientfd 0)return -1;strcpy(ip, inet_ntoa(addr.sin_addr));*port ntohs(addr.sin_port);return clientfd;
}static char* getLineFromBuf(char* buf, char* line) {while (*buf ! \n){*line *buf;line;buf;}*line \n;line;*line \0;buf;return buf;
}static int handleCmd_OPTIONS(char* result, int cseq) {sprintf(result, RTSP/1.0 200 OK\r\nCSeq: %d\r\nPublic: OPTIONS, DESCRIBE, SETUP, PLAY\r\n\r\n,cseq);return 0;
}static int handleCmd_DESCRIBE(char* result, int cseq, char* url) {char sdp[500];char localIp[100];sscanf(url, rtsp://%[^:]:, localIp);sprintf(sdp, v0\r\no- 9%ld 1 IN IP4 %s\r\nt0 0\r\nacontrol:*\r\nmaudio 0 RTP/AVP 97\r\nartpmap:97 mpeg4-generic/44100/2\r\nafmtp:97 profile-level-id1;modeAAC-hbr;sizelength13;indexlength3;indexdeltalength3;config1210;\r\n//afmtp:97 SizeLength13;\r\nacontrol:track0\r\n,time(NULL), localIp);sprintf(result, RTSP/1.0 200 OK\r\nCSeq: %d\r\nContent-Base: %s\r\nContent-type: application/sdp\r\nContent-length: %d\r\n\r\n%s,cseq,url,strlen(sdp),sdp);return 0;
}static int handleCmd_SETUP(char* result, int cseq, int clientRtpPort) {sprintf(result, RTSP/1.0 200 OK\r\nCSeq: %d\r\nTransport: RTP/AVP;unicast;client_port%d-%d;server_port%d-%d\r\nSession: 66334873\r\n\r\n,cseq,clientRtpPort,clientRtpPort 1,SERVER_RTP_PORT,SERVER_RTCP_PORT);return 0;
}static int handleCmd_PLAY(char* result, int cseq) {sprintf(result, RTSP/1.0 200 OK\r\nCSeq: %d\r\nRange: npt0.000-\r\nSession: 66334873; timeout10\r\n\r\n,cseq);return 0;
}static void doClient(int clientSockfd, const char* clientIP, int clientPort) {int serverRtpSockfd -1, serverRtcpSockfd -1;char method[40];char url[100];char version[40];int CSeq;int clientRtpPort, clientRtcpPort;char* rBuf (char*)malloc(BUF_MAX_SIZE);char* sBuf (char*)malloc(BUF_MAX_SIZE);while (true) {int recvLen;recvLen recv(clientSockfd, rBuf, BUF_MAX_SIZE, 0);if (recvLen 0) {break;}rBuf[recvLen] \0;printf(%s rBuf %s \n, __FUNCTION__, rBuf);const char* sep \n;char* line strtok(rBuf, sep);while (line) {if (strstr(line, OPTIONS) ||strstr(line, DESCRIBE) ||strstr(line, SETUP) ||strstr(line, PLAY)) {if (sscanf(line, %s %s %s\r\n, method, url, version) ! 3) {// error}}else if (strstr(line, CSeq)) {if (sscanf(line, CSeq: %d\r\n, CSeq) ! 1) {// error}}else if (!strncmp(line, Transport:, strlen(Transport:))) {// Transport: RTP/AVP/UDP;unicast;client_port13358-13359// Transport: RTP/AVP;unicast;client_port13358-13359if (sscanf(line, Transport: RTP/AVP/UDP;unicast;client_port%d-%d\r\n,clientRtpPort, clientRtcpPort) ! 2) {// errorprintf(parse Transport error \n);}}line strtok(NULL, sep);}if (!strcmp(method, OPTIONS)) {if (handleCmd_OPTIONS(sBuf, CSeq)){printf(failed to handle options\n);break;}}else if (!strcmp(method, DESCRIBE)) {if (handleCmd_DESCRIBE(sBuf, CSeq, url)){printf(failed to handle describe\n);break;}}else if (!strcmp(method, SETUP)) {if (handleCmd_SETUP(sBuf, CSeq, clientRtpPort)){printf(failed to handle setup\n);break;}serverRtpSockfd createUdpSocket();serverRtcpSockfd createUdpSocket();if (serverRtpSockfd 0 || serverRtcpSockfd 0){printf(failed to create udp socket\n);break;}if (bindSocketAddr(serverRtpSockfd, 0.0.0.0, SERVER_RTP_PORT) 0 ||bindSocketAddr(serverRtcpSockfd, 0.0.0.0, SERVER_RTCP_PORT) 0){printf(failed to bind addr\n);break;}}else if (!strcmp(method, PLAY)) {if (handleCmd_PLAY(sBuf, CSeq)){printf(failed to handle play\n);break;}}else {printf(δmethod %s \n, method);break;}printf(%s sBuf %s \n, __FUNCTION__, sBuf);send(clientSockfd, sBuf, strlen(sBuf), 0);//ʼţRTPif (!strcmp(method, PLAY)) {struct AdtsHeader adtsHeader;struct RtpPacket* rtpPacket;uint8_t* frame;int ret;FILE* fp fopen(AAC_FILE_NAME, rb);if (!fp) {printf(ȡ %s ʧ\n, AAC_FILE_NAME);break;}frame (uint8_t*)malloc(5000);rtpPacket (struct RtpPacket*)malloc(5000);rtpHeaderInit(rtpPacket, 0, 0, 0, RTP_VESION, RTP_PAYLOAD_TYPE_AAC, 1, 0, 0, 0x32411);while (true){ret fread(frame, 1, 7, fp);if (ret 0){printf(fread err\n);break;}printf(fread ret%d \n,ret);if (parseAdtsHeader(frame, adtsHeader) 0){printf(parseAdtsHeader err\n);break;}ret fread(frame, 1, adtsHeader.aacFrameLength - 7, fp);if (ret 0){printf(fread err\n);break;}rtpSendAACFrame(serverRtpSockfd, clientIP, clientRtpPort,rtpPacket, frame, adtsHeader.aacFrameLength - 7);Sleep(1);//usleep(23223);//1000/43.06 * 1000}free(frame);free(rtpPacket);break;}memset(method, 0, sizeof(method) / sizeof(char));memset(url, 0, sizeof(url) / sizeof(char));CSeq 0;}closesocket(clientSockfd);if (serverRtpSockfd) {closesocket(serverRtpSockfd);}if (serverRtcpSockfd 0) {closesocket(serverRtcpSockfd);}free(rBuf);free(sBuf);}int main() {// windows socket startWSADATA wsaData;if (WSAStartup(MAKEWORD(2, 2), wsaData) ! 0){printf(PC Server Socket Start Up Error \n);return -1;}// windows socket endint rtspServerSockfd;int ret;rtspServerSockfd createTcpSocket();if (rtspServerSockfd 0){printf(failed to create tcp socket\n);return -1;}ret bindSocketAddr(rtspServerSockfd, 0.0.0.0, SERVER_PORT);if (ret 0){printf(failed to bind addr\n);return -1;}ret listen(rtspServerSockfd, 10);if (ret 0){printf(failed to listen\n);return -1;}printf(%s rtsp://127.0.0.1:%d\n, __FILE__, SERVER_PORT);while (1){int clientSockfd;char clientIp[40];int clientPort;clientSockfd acceptClient(rtspServerSockfd, clientIp, clientPort);if (clientSockfd 0){printf(failed to accept client\n);return -1;}printf(accept client;client ip:%s,client port:%d\n, clientIp, clientPort);doClient(clientSockfd, clientIp, clientPort);}closesocket(rtspServerSockfd);return 0;
}
rtp.cpp
#include sys/types.h
#include WinSock2.h
#include WS2tcpip.h
#include windows.h
#include rtp.hvoid rtpHeaderInit(struct RtpPacket* rtpPacket, uint8_t csrcLen, uint8_t extension,uint8_t padding, uint8_t version, uint8_t payloadType, uint8_t marker,uint16_t seq, uint32_t timestamp, uint32_t ssrc)
{rtpPacket-rtpHeader.csrcLen csrcLen;rtpPacket-rtpHeader.extension extension;rtpPacket-rtpHeader.padding padding;rtpPacket-rtpHeader.version version;rtpPacket-rtpHeader.payloadType payloadType;rtpPacket-rtpHeader.marker marker;rtpPacket-rtpHeader.seq seq;rtpPacket-rtpHeader.timestamp timestamp;rtpPacket-rtpHeader.ssrc ssrc;
}
int rtpSendPacketOverTcp(int clientSockfd, struct RtpPacket* rtpPacket, uint32_t dataSize)
{rtpPacket-rtpHeader.seq htons(rtpPacket-rtpHeader.seq);rtpPacket-rtpHeader.timestamp htonl(rtpPacket-rtpHeader.timestamp);rtpPacket-rtpHeader.ssrc htonl(rtpPacket-rtpHeader.ssrc);uint32_t rtpSize RTP_HEADER_SIZE dataSize;char* tempBuf (char *)malloc(4 rtpSize);tempBuf[0] 0x24;//$tempBuf[1] 0x00;tempBuf[2] (uint8_t)(((rtpSize) 0xFF00) 8);tempBuf[3] (uint8_t)((rtpSize) 0xFF);memcpy(tempBuf 4, (char*)rtpPacket, rtpSize);int ret send(clientSockfd, tempBuf, 4 rtpSize, 0);rtpPacket-rtpHeader.seq ntohs(rtpPacket-rtpHeader.seq);rtpPacket-rtpHeader.timestamp ntohl(rtpPacket-rtpHeader.timestamp);rtpPacket-rtpHeader.ssrc ntohl(rtpPacket-rtpHeader.ssrc);free(tempBuf);tempBuf NULL;return ret;
}
int rtpSendPacketOverUdp(int serverRtpSockfd, const char* ip, int16_t port, struct RtpPacket* rtpPacket, uint32_t dataSize)
{struct sockaddr_in addr;int ret;addr.sin_family AF_INET;addr.sin_port htons(port);addr.sin_addr.s_addr inet_addr(ip);rtpPacket-rtpHeader.seq htons(rtpPacket-rtpHeader.seq);rtpPacket-rtpHeader.timestamp htonl(rtpPacket-rtpHeader.timestamp);rtpPacket-rtpHeader.ssrc htonl(rtpPacket-rtpHeader.ssrc);ret sendto(serverRtpSockfd, (char *)rtpPacket, dataSize RTP_HEADER_SIZE, 0,(struct sockaddr*)addr, sizeof(addr));rtpPacket-rtpHeader.seq ntohs(rtpPacket-rtpHeader.seq);rtpPacket-rtpHeader.timestamp ntohl(rtpPacket-rtpHeader.timestamp);rtpPacket-rtpHeader.ssrc ntohl(rtpPacket-rtpHeader.ssrc);return ret;}rtp.h
#pragma once
#pragma comment(lib, ws2_32.lib)
#include stdint.h#define RTP_VESION 2#define RTP_PAYLOAD_TYPE_H264 96
#define RTP_PAYLOAD_TYPE_AAC 97#define RTP_HEADER_SIZE 12
#define RTP_MAX_PKT_SIZE 1400/** 0 1 2 3* 7 6 5 4 3 2 1 0|7 6 5 4 3 2 1 0|7 6 5 4 3 2 1 0|7 6 5 4 3 2 1 0* --------------------------------* |V2|P|X| CC |M| PT | sequence number |* --------------------------------* | timestamp |* --------------------------------* | synchronization source (SSRC) identifier |* * | contributing source (CSRC) identifiers |* : .... :* --------------------------------**/
struct RtpHeader
{/* byte 0 */uint8_t csrcLen : 4;uint8_t extension : 1;uint8_t padding : 1;uint8_t version : 2;/* byte 1 */uint8_t payloadType : 7;uint8_t marker : 1;/* bytes 2,3 */uint16_t seq;/* bytes 4-7 */uint32_t timestamp;/* bytes 8-11 */uint32_t ssrc;
};struct RtpPacket
{struct RtpHeader rtpHeader;uint8_t payload[0];
};void rtpHeaderInit(struct RtpPacket* rtpPacket, uint8_t csrcLen, uint8_t extension,uint8_t padding, uint8_t version, uint8_t payloadType, uint8_t marker,uint16_t seq, uint32_t timestamp, uint32_t ssrc);int rtpSendPacketOverTcp(int clientSockfd, struct RtpPacket* rtpPacket, uint32_t dataSize);
int rtpSendPacketOverUdp(int serverRtpSockfd, const char* ip, int16_t port, struct RtpPacket* rtpPacket, uint32_t dataSize);
