func UnpackRTP2H264(rtpPayload []byte) []byte {
if len(rtpPayload) <= 0 {
return nil
}
var out []byte
fu_indicator := rtpPayload[0] //获取第一个字节
fu_header := rtpPayload[1] //获取第二个字节
nalu_type := fu_indicator & 0x1f //获取FU indicator的类型域
flag := fu_header & 0xe0 //获取FU header的前三位，判断当前是分包的开始、中间或结束
nal_fua := ((fu_indicator & 0xe0) | (fu_header & 0x1f)) //FU_A nal
var FrameType string
if nal_fua == 0x67 {
FrameType = "SPS"
} else if nal_fua == 0x68 {
FrameType = "PPS"
} else if nal_fua == 0x65 {
FrameType = "IDR"
} else if nal_fua == 0x61 {
FrameType = "P Frame"
} else if nal_fua == 0x41 {
FrameType = "P Frame"
}
log.Printf("nalu_type: %x flag: %x FrameType: %s", nalu_type, flag, FrameType)
if nalu_type == 0x1c { //判断NAL的类型为0x1c=28，说明是FU-A分片
if flag == 0x80 { //分片NAL单元开始位
/*
o := make([]byte, len(rtpPayload)+5-2) //I帧开头可能为00 00 00 01、00 00 01，组帧时只用00 00 01开头
o[0] = 0x00
o[1] = 0x00
o[2] = 0x00
o[3] = 0x01
o[4] = nal_fua*/
o := make([]byte, len(rtpPayload)+4-2) //I帧开头可能为00 00 00 01、00 00 01，组帧时只用00 00 01开头
o[0] = 0x00
o[1] = 0x00
o[2] = 0x01
o[3] = nal_fua
copy(o[4:], rtpPayload[2:])
out = o
} else { //中间分片包或者最后一个分片包
o := make([]byte, len(rtpPayload)-2)
copy(o[0:], rtpPayload[2:])
out = o
}
} else if nalu_type == 0x1 { //单一NAL 单元模式
o := make([]byte, len(rtpPayload)+4) //将整个rtpPayload一起放进去
o[0] = 0x00
o[1] = 0x00
o[2] = 0x00
o[3] = 0x01
copy(o[4:], rtpPayload[0:])
out = o
} else {
log.Printf("Unsport nalu type!")
}
return out
}