使用librtmp库发送音频，视频数据包

1. libRTMP的包结构

typedef struct RTMPPacket  
{  
  uint8_t  m_headerType;     
  uint8_t  m_packetType;  
  uint8_t  m_hasAbsTimestamp;     
  int      m_nChannel;  
  uint32_t m_nTimeStamp;      
  int32_t  m_nInfoField2;     
  uint32_t m_nBodySize;  
  uint32_t m_nBytesRead;  
  RTMPChunk *m_chunk;  
  char    *m_body;  
} RTMPPacket; 

packet->m_headerType： 可以定义如下：

#define RTMP_PACKET_SIZE_LARGE    0  
#define RTMP_PACKET_SIZE_MEDIUM   1  
#define RTMP_PACKET_SIZE_SMALL    2  
#define RTMP_PACKET_SIZE_MINIMUM  3  

一般定位为 RTMP_PACKET_SIZE_MEDIUM

packet->m_packetType： 音频、视频包类型

#define RTMP_PACKET_TYPE_AUDIO    0x08  
#define RTMP_PACKET_TYPE_VIDEO    0x09  
#define RTMP_PACKET_TYPE_INFO     0x12   

还有其他更多类型，但一般都是 音频或视频

packet->m_hasAbsTimestamp： 是否使用绝对时间戳，一般定义为0。

packet->m_nChannel：音视频通道号码，音视频不要写错，

#define STREAM_CHANNEL_METADATA  0x03  
#define STREAM_CHANNEL_VIDEO     0x04  
#define STREAM_CHANNEL_AUDIO     0x05  

 

packet->m_nTimeStamp：时间戳
一般视频时间戳可以从0开始计算，每帧时间戳 + 1000/fps (25fps每帧递增25；30fps递增33)
音频时间戳也可以从0开始计算，48K采样每帧递增21；44.1K采样每帧递增23。

packet->m_nInfoField2 = rtmp->m_stream_id

packet->m_nBodySize：数据包长度 = NALU包长度 + 包头长度

packet->m_nBytesRead：不用管
packet->m_chunk： 不用管
packet->m_body：包头数据 + NALU数据，其长度为packet->m_nBodySize。

 

2. 发送视频SPS，PPS包

 

int rtmp_write_video_header(RTMP *rtmp) {  
    int size = 10 + 3 + sps_pps.sps_length + 3 + sps_pps.pps_length;  
  
    RTMPPacket packet;  
    RTMPPacket_Reset(&packet);  
    RTMPPacket_Alloc(&packet, size);  
    unsigned char *body = packet.m_body;  
  
    int i = 0;  
    body[i++] = 0x17;  
    body[i++] = 0x00;  
  
    body[i++] = 0x00;  
    body[i++] = 0x00;  
    body[i++] = 0x00;  
  
    //AVCDecoderConfigurationRecord  
    body[i++] = 0x01;  
    body[i++] = sps_pps.sps_data[1];  
    body[i++] = sps_pps.sps_data[2];  
    body[i++] = sps_pps.sps_data[3];  
    body[i++] = 0xFF;  
  
    //sps  
    body[i++] = 0xE1;  
    body[i++] = (sps_pps.sps_length >> 8) & 0xFF;  
    body[i++] =  sps_pps.sps_length       & 0xFF;  
    memcpy(&body[i], sps_pps.sps_data, sps_pps.sps_length);  // 复制sps数据  
    i +=  sps_pps.sps_length;  
  
    // pps  
    body[i++] = 0x01;  
    body[i++] = (sps_pps.pps_length >> 8) & 0xFF;  
    body[i++] =  sps_pps.pps_length       & 0xFF;  
    memcpy(&body[i], sps_pps.pps_data, sps_pps.pps_length);  // 复制pps数据  
    i +=  sps_pps.pps_length;  
  
    packet->m_headerType  = RTMP_PACKET_SIZE_MEDIUM;  
    packet->m_packetType = RTMP_PACKET_TYPE_VIDEO;  
    packet->m_hasAbsTimestamp = 0;  
    packet->m_nChannel   = STREAM_CHANNEL_VIDEO;  
    packet->m_nTimeStamp = 0;  
    packet->m_nInfoField2 = rtmp->m_stream_id;  
    packet->m_nBodySize  = size;  
  
    //调用发送接口  
    int nRet = RTMP_SendPacket(rtmp, packet, TRUE);  
    RTMPPacket_Free(&packet);  
    return nRet;  
}  

在最开始发送一次即可。

3. 发送视频数据包

int rtmp_write_video_frame(RTMP *rtmp, const BYTE *nalu_data, int slice_count, int nTimestamp){  
    int n;  
    int nRet =0;  
    int size = 0;  
    for(n=0; nm_stream_id;  
    packet.m_nBodySize  = size;  
  
    for(n=0; n

4. 发送音频头包

 

int rtmp_write_audio_header(RTMP *rtmp){  
    RTMPPacket packet;  
    RTMPPacket_Reset(&packet);  
    RTMPPacket_Alloc(&packet, 4);  
  
    packet.m_body[0] = 0xAF;  // MP3 AAC format 48000Hz  
    packet.m_body[1] = 0x00;  
    packet.m_body[2] = 0x11;  
    packet.m_body[3] = 0x90;//0x10修改为0x90,2016-1-19  
  
    packet.m_headerType  = RTMP_PACKET_SIZE_MEDIUM;  
    packet.m_packetType = RTMP_PACKET_TYPE_AUDIO;  
    packet.m_hasAbsTimestamp = 0;  
    packet.m_nChannel   = STREAM_CHANNEL_AUDIO;  
    packet.m_nTimeStamp = 0;  
    packet.m_nInfoField2 = rtmp->m_stream_id;  
    packet.m_nBodySize  = 4;  
  
    //调用发送接口  
    int nRet = RTMP_SendPacket(rtmp, &packet, TRUE);  
    RTMPPacket_Free(&packet);//释放内存  
    return nRet;  
}  

在最开始发送一次即可。

5. 发送音频包

int rtmp_write_audio_data(RTMP *rtmp, const BYTE *nalu_data, int nalu_size, int audio_TimeStamp){  
    //rtmp包结构  
    int size = nalu_size + 2;  
    RTMPPacket packet;  
    RTMPPacket_Reset(&packet);  
    RTMPPacket_Alloc(&packet, size);  
  
    int i=0;  
    // MP3 AAC format 48000Hz  
    packet.m_body[i++] = 0xAF;  
    packet.m_body[i++] = 0x01;  
    memcpy(&packet.m_body[i], nalu_data, nalu_size);  
  
    packet.m_headerType  = RTMP_PACKET_SIZE_MEDIUM;  
    packet.m_packetType = RTMP_PACKET_TYPE_AUDIO;  
    packet.m_hasAbsTimestamp = 0;  
    packet.m_nChannel   = STREAM_CHANNEL_AUDIO;  
    packet.m_nTimeStamp = audio_TimeStamp;  
    packet.m_nInfoField2 = rtmp->m_stream_id;  
    packet.m_nBodySize  = size;  
  
    //调用发送接口  
    int nRet = RTMP_SendPacket(rtmp, &packet, TRUE);  
    RTMPPacket_Free(&packet);//释放内存  
    return nRet;  
}  

6. 本地存储packet

int RTMP_SendPacket_wrap(RTMP_ *rtmp, RTMPPacket *packet, int queue){  
#if OUTPUT_FLV  
    uint8_t data[] = {0x09,  
        0x00, 0x00, 0x00,  
        0x00, 0x00, 0x00, 0x00,  
        0x00, 0x00, 0x00 };  
    if(packet->m_packetType == RTMP_PACKET_TYPE_VIDEO){  
        data[0] = 0x09;  
    } else if(packet->m_packetType == RTMP_PACKET_TYPE_AUDIO){  
        data[0] = 0x08;  
    }  
    int len = 0;  
    int_to_bytes(packet->m_nBodySize,  &data[1], 3);  // 3字节 包内容长度  
    int_to_bytes(packet->m_nTimeStamp, &data[4], 3);  // 3字节 时间戳，没用第4字节，太长的文件会溢出  
    len += fwrite(data, 1, 11, flv_fp);               // 写入包头11字节  
    len += fwrite(packet->m_body, 1, packet->m_nBodySize, flv_fp); // 写入数据包体  
    int_to_bytes(len, &data[0], 4);                   // 写入的总字节长度  
    fwrite(data, 1, 4, flv_fp);                       // 等于前Tag总长度  
#endif  
    return RTMP_SendPacket(rtmp, packet, queue);  
}