RTMPdump（libRTMP） 源代码分析 9： 接收消息（Message）（接收视音频数据）(六)
Type == 0x16)
{
unsigned int pos = 0;
int delta;
/* grab first timestamp and see if it needs fixing */
// nTimeStamp = AMF_DecodeInt24(packetBody + 4);
// nTimeStamp |= (packetBody[7] << 24);
// delta = packet.m_nTimeStamp - nTimeStamp;
while (pos + 11 < nPacketLen)
{
/* size without header (11) and without prevTagSize (4) */
uint32_t dataSize = AMF_DecodeInt24(packetBody + pos + 1);
nTimeStamp = AMF_DecodeInt24(packetBody + pos + 4);
nTimeStamp |= (packetBody[pos + 7] << 24);
// if (delta)
// {
// nTimeStamp += delta;
// AMF_EncodeInt24(ptr+pos+4, pend, nTimeStamp);
// ptr[pos+7] = nTimeStamp>>24;
// }
/* set data type */
r->m_read.dataType |= (((*(packetBody + pos) == 0x08) << 2) |
(*(packetBody + pos) == 0x09));
if (pos + 11 + dataSize + 4 > nPacketLen)
{
if (pos + 11 + dataSize > nPacketLen)
{
RTMP_Log(RTMP_LOGERROR,
"Wrong data size (%lu), stream corrupted, aborting!",
dataSize);
ret = RTMP_READ_ERROR;
break;
}
RTMP_Log(RTMP_LOGWARNING, "No tagSize found, appending!");
/* we have to append a last tagSize! */
prevTagSize = dataSize + 11;
AMF_EncodeInt32(ptr + pos + 11 + dataSize, pend,
prevTagSize);
size += 4;
len += 4;
}
else
{
prevTagSize =
AMF_DecodeInt32(packetBody + pos + 11 + dataSize);
#ifdef _DEBUG
RTMP_Log(RTMP_LOGDEBUG,
"FLV Packet: type %02X, dataSize: %lu, tagSize: %lu, timeStamp: %lu ms",
(unsigned char)packetBody[pos], dataSize, prevTagSize,
nTimeStamp);
#endif
if (prevTagSize != (dataSize + 11))
{
#ifdef _DEBUG
RTMP_Log(RTMP_LOGWARNING,
"Tag and data size are not consitent, writing tag size according to dataSize+11: %d",
dataSize + 11);
#endif
prevTagSize = dataSize + 11;
AMF_EncodeInt32(ptr + pos + 11 + dataSize, pend,
prevTagSize);
}
}
pos += prevTagSize + 4; /*(11+dataSize+4); */
}
}
ptr += len;
if (packet.m_packetType != 0x16)
{
/* FLV tag packets contain their own prevTagSize */
AMF_EncodeInt32(ptr, pend, prevTagSize);
}
/* In non-live this nTimeStamp can contain an absolute TS.
* Update ext timestamp with this absolute offset in non-live mode
* otherwise report the relative one
*/
/* RTMP_Log(RTMP_LOGDEBUG, "type: %02X, size: %d, pktTS: %dms, TS: %dms, bLiveStream: %d", packet.m_packetType, nPacketLen, packet.m_nTimeStamp, nTimeStamp, r->Link.lFlags & RTMP_LF_LIVE); */
r->m_read.timestamp = (r->Link.lFlags & RTMP_LF_LIVE) packet.m_nTimeStamp : nTimeStamp;
ret = size;
break;
}
if (rtnGetNextMediaPacket)
RTMPPacket_Free(&packet);
if (recopy)
{
len = ret > buflen buflen : ret;
memcpy(buf, r->m_read.buf, len);
r->m_read.bufpos = r->m_read.buf + len;
r->m_read.buflen = ret - len;
}
return ret;
}
函数功能很多，重要的地方已经加上了注释，在此不再细分析。