使用golang解析rtp成H264裸码流

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

}