1. libRTMP的包結構
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: 可以定義如下:
#define RTMP_PACKET_SIZE_LARGE 0
#define RTMP_PACKET_SIZE_MEDIUM 1
#define RTMP_PACKET_SIZE_SMALL 2
#define RTMP_PACKET_SIZE_MINIMUM 3
一般定位爲 RTMP_PACKET_SIZE_MEDIUM
packet->m_packetType: 音頻、視頻包類型
#define RTMP_PACKET_TYPE_AUDIO 0x08
#define RTMP_PACKET_TYPE_VIDEO 0x09
#define RTMP_PACKET_TYPE_INFO 0x12
還有其他更多類型,但一般都是 音頻或視頻
packet->m_hasAbsTimestamp: 是否使用絕對時間戳,一般定義爲0。
packet->m_nChannel:音視頻通道號碼,音視頻不要寫錯,
#define STREAM_CHANNEL_METADATA 0x03
#define STREAM_CHANNEL_VIDEO 0x04
#define STREAM_CHANNEL_AUDIO 0x05
packet->m_nTimeStamp:時間戳
一般視頻時間戳可以從0開始計算,每幀時間戳 + 1000/fps (25fps每幀遞增25;30fps遞增33)
音頻時間戳也可以從0開始計算,48K採樣每幀遞增21;44.1K採樣每幀遞增23。
packet->m_nInfoField2 = rtmp->m_stream_id
packet->m_nBodySize:數據包長度 = NALU包長度 + 包頭長度
packet->m_nBytesRead:不用管
packet->m_chunk: 不用管
packet->m_body:包頭數據 + NALU數據,其長度爲packet->m_nBodySize。
2. 發送視頻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); // 複製sps數據
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); // 複製pps數據
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;
//調用發送接口
int nRet = RTMP_SendPacket(rtmp, packet, TRUE);
RTMPPacket_Free(&packet);
return nRet;
}
在最開始發送一次即可。
3. 發送視頻數據包
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; n<slice_count; n++)
size += (slice[n].slice_length + 4); // 每個slice數據前要加4字節的slice長度
size += 5; // 5字節頭
RTMPPacket packet;
RTMPPacket_Reset(&packet);
RTMPPacket_Alloc(&packet, size);
unsigned char *body = packet.m_body;
// NALU size
int i=0;
body[0] = ((slice[0].slice_type&0x1F) == 0x5) ? 0x17 : 0x27;
body[1] = 0x01; // AVC NALU
body[2] = 0x00;
body[3] = 0x00;
body[4] = 0x00;
i=5;
//包體內存
packet.m_headerType = RTMP_PACKET_SIZE_LARGE;
packet.m_packetType = RTMP_PACKET_TYPE_VIDEO;
packet.m_hasAbsTimestamp = 0;
packet.m_nChannel = STREAM_CHANNEL_VIDEO;
packet.m_nTimeStamp = nTimestamp;
packet.m_nInfoField2 = rtmp->m_stream_id;
packet.m_nBodySize = size;
for(n=0; n<slice_count; n++) {
int len = slice[n].slice_length;
int_to_bytes(len, &body[i], 4);
i+=4;
memcpy(&body[i], nalu_data + slice[n].start_address, len);
i += len;
}
//發送
if (RTMP_IsConnected(rtmp)){
nRet = RTMP_SendPacket(rtmp, &packet, TRUE); //TRUE爲放進發送隊列,FALSE是不放進發送隊列,直接發送
if(nRet <= 0) {
printf("RTMP_SendPacket Error\n");
}
}
//釋放內存
RTMPPacket_Free(&packet);
return nRet;
}
4. 發送音頻頭包
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修改爲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;
//調用發送接口
int nRet = RTMP_SendPacket(rtmp, &packet, TRUE);
RTMPPacket_Free(&packet);//釋放內存
return nRet;
}
在最開始發送一次即可。
5. 發送音頻包
int rtmp_write_audio_data(RTMP *rtmp, const BYTE *nalu_data, int nalu_size, int audio_TimeStamp){
//rtmp包結構
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;
//調用發送接口
int nRet = RTMP_SendPacket(rtmp, &packet, TRUE);
RTMPPacket_Free(&packet);//釋放內存
return nRet;
}
6. 本地存儲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字節 包內容長度
int_to_bytes(packet->m_nTimeStamp, &data[4], 3); // 3字節 時間戳,沒用第4字節,太長的文件會溢出
len += fwrite(data, 1, 11, flv_fp); // 寫入包頭11字節
len += fwrite(packet->m_body, 1, packet->m_nBodySize, flv_fp); // 寫入數據包體
int_to_bytes(len, &data[0], 4); // 寫入的總字節長度
fwrite(data, 1, 4, flv_fp); // 等於前Tag總長度
#endif
return RTMP_SendPacket(rtmp, packet, queue);
}