RTMPdump（libRTMP）源代码分析 7：建立一个流媒体连接（NetStream部分 2）

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Ai_Yang 2021-07-06 16:21:45

文章标签 流媒体 文章分类 Android 移动开发

RTMPdump 源代码分析 1： main()函数

RTMPdump (libRTMP) 源代码分析4：连接第一步——握手 (HandShake)

RTMPdump (libRTMP) 源代码分析7：建立一个流媒体连接 (NetStream部分 2)

RTMPdump (libRTMP) 源代码分析10：处理各种消息 (Message)

函数调用结构图

上回说到，有两个函数尤为重要：

[cpp] view plain copy

//处理接收到的Chunk
int
RTMP_ClientPacket(RTMP *r, RTMPPacket *packet)
{
int bHasMediaPacket = 0;
switch (packet->m_packetType)
{
//RTMP消息类型ID=1,设置块大小
case 0x01:
/* chunk size */
//----------------
r->dlg->AppendCInfo("处理收到的数据。消息 Set Chunk Size (typeID=1)。");
//-----------------------------
RTMP_LogPrintf("处理消息 Set Chunk Size (typeID=1)\n");
HandleChangeChunkSize(r, packet);
break;
//RTMP消息类型ID=3，致谢
case 0x03:
/* bytes read report */
RTMP_Log(RTMP_LOGDEBUG, "%s, received: bytes read report", __FUNCTION__);
break;
//RTMP消息类型ID=4，用户控制
case 0x04:
/* ctrl */
//----------------
r->dlg->AppendCInfo("处理收到的数据。消息 User Control (typeID=4)。");
//-----------------------------
RTMP_LogPrintf("处理消息 User Control (typeID=4)\n");
HandleCtrl(r, packet);
break;
//RTMP消息类型ID=5
case 0x05:
/* server bw */
//----------------
r->dlg->AppendCInfo("处理收到的数据。消息 Window Acknowledgement Size (typeID=5)。");
//-----------------------------
RTMP_LogPrintf("处理消息 Window Acknowledgement Size (typeID=5)\n");
HandleServerBW(r, packet);
break;
//RTMP消息类型ID=6
case 0x06:
/* client bw */
//----------------
r->dlg->AppendCInfo("处理收到的数据。消息 Set Peer Bandwidth (typeID=6)。");
//-----------------------------
RTMP_LogPrintf("处理消息 Set Peer Bandwidth (typeID=6)\n");
HandleClientBW(r, packet);
break;
//RTMP消息类型ID=8，音频数据
case 0x08:
/* audio data */
/*RTMP_Log(RTMP_LOGDEBUG, "%s, received: audio %lu bytes", __FUNCTION__, packet.m_nBodySize); */
HandleAudio(r, packet);
bHasMediaPacket = 1;
if (!r->m_mediaChannel)
r->m_mediaChannel = packet->m_nChannel;
if (!r->m_pausing)
r->m_mediaStamp = packet->m_nTimeStamp;
break;
//RTMP消息类型ID=9，视频数据
case 0x09:
/* video data */
/*RTMP_Log(RTMP_LOGDEBUG, "%s, received: video %lu bytes", __FUNCTION__, packet.m_nBodySize); */
HandleVideo(r, packet);
bHasMediaPacket = 1;
if (!r->m_mediaChannel)
r->m_mediaChannel = packet->m_nChannel;
if (!r->m_pausing)
r->m_mediaStamp = packet->m_nTimeStamp;
break;
//RTMP消息类型ID=15，AMF3编码，忽略
case 0x0F: /* flex stream send */
RTMP_Log(RTMP_LOGDEBUG,
"%s, flex stream send, size %lu bytes, not supported, ignoring",
__FUNCTION__, packet->m_nBodySize);
break;
//RTMP消息类型ID=16，AMF3编码，忽略
case 0x10: /* flex shared object */
RTMP_Log(RTMP_LOGDEBUG,
"%s, flex shared object, size %lu bytes, not supported, ignoring",
__FUNCTION__, packet->m_nBodySize);
break;
//RTMP消息类型ID=17，AMF3编码，忽略
case 0x11: /* flex message */
{
RTMP_Log(RTMP_LOGDEBUG,
"%s, flex message, size %lu bytes, not fully supported",
__FUNCTION__, packet->m_nBodySize);
/*RTMP_LogHex(packet.m_body, packet.m_nBodySize); */
/* some DEBUG code */
#if 0
RTMP_LIB_AMFObject obj;
int nRes = obj.Decode(packet.m_body+1, packet.m_nBodySize-1);
if(nRes < 0) {
RTMP_Log(RTMP_LOGERROR, "%s, error decoding AMF3 packet", __FUNCTION__);
/*return; */
}
obj.Dump();
#endif
if (HandleInvoke(r, packet->m_body + 1, packet->m_nBodySize - 1) == 1)
bHasMediaPacket = 2;
break;
}
//RTMP消息类型ID=18，AMF0编码，数据消息
case 0x12:
/* metadata (notify) */
RTMP_Log(RTMP_LOGDEBUG, "%s, received: notify %lu bytes", __FUNCTION__,
packet->m_nBodySize);
//处理元数据,暂时注释
/*
if (HandleMetadata(r, packet->m_body, packet->m_nBodySize))
bHasMediaPacket = 1;
break;
*/
//RTMP消息类型ID=19，AMF0编码，忽略
case 0x13:
RTMP_Log(RTMP_LOGDEBUG, "%s, shared object, not supported, ignoring",
__FUNCTION__);
break;
//RTMP消息类型ID=20，AMF0编码，命令消息
//处理命令消息！
case 0x14:
//----------------
r->dlg->AppendCInfo("处理收到的数据。消息命令 (AMF0编码) (typeID=20)。");
//-----------------------------
/* invoke */
RTMP_Log(RTMP_LOGDEBUG, "%s, received: invoke %lu bytes", __FUNCTION__,
packet->m_nBodySize);
RTMP_LogPrintf("处理命令消息 (typeID=20，AMF0编码)\n");
/*RTMP_LogHex(packet.m_body, packet.m_nBodySize); */
if (HandleInvoke(r, packet->m_body, packet->m_nBodySize) == 1)
bHasMediaPacket = 2;
break;
//RTMP消息类型ID=22
case 0x16:
{
/* go through FLV packets and handle metadata packets */
unsigned int pos = 0;
uint32_t nTimeStamp = packet->m_nTimeStamp;
while (pos + 11 < packet->m_nBodySize)
{
uint32_t dataSize = AMF_DecodeInt24(packet->m_body + pos + 1); /* size without header (11) and prevTagSize (4) */
if (pos + 11 + dataSize + 4 > packet->m_nBodySize)
{
RTMP_Log(RTMP_LOGWARNING, "Stream corrupt?!");
break;
}
if (packet->m_body[pos] == 0x12)
{
HandleMetadata(r, packet->m_body + pos + 11, dataSize);
}
else if (packet->m_body[pos] == 8 || packet->m_body[pos] == 9)
{
nTimeStamp = AMF_DecodeInt24(packet->m_body + pos + 4);
nTimeStamp |= (packet->m_body[pos + 7] << 24);
}
pos += (11 + dataSize + 4);
}
if (!r->m_pausing)
r->m_mediaStamp = nTimeStamp;
/* FLV tag(s) */
/*RTMP_Log(RTMP_LOGDEBUG, "%s, received: FLV tag(s) %lu bytes", __FUNCTION__, packet.m_nBodySize); */
bHasMediaPacket = 1;
break;
}
default:
RTMP_Log(RTMP_LOGDEBUG, "%s, unknown packet type received: 0x%02x", __FUNCTION__,
packet->m_packetType);
#ifdef _DEBUG
RTMP_LogHex(RTMP_LOGDEBUG, (const uint8_t *)packet->m_body, packet->m_nBodySize);
#endif
}
return bHasMediaPacket;
}