// Copyright 2020, Chef. All rights reserved. // https://github.com/q191201771/lal // // Use of this source code is governed by a MIT-style license // that can be found in the License file. // // Author: Chef (191201771@qq.com) package rtprtcp import ( "github.com/q191201771/lal/pkg/base" "github.com/q191201771/naza/pkg/bele" "github.com/q191201771/naza/pkg/nazalog" ) func calcPositionIfNeededAVC(pkt *RTPPacket) { b := pkt.Raw[pkt.Header.payloadOffset:] // rfc3984 5.3. NAL Unit Octet Usage // // +---------------+ // |0|1|2|3|4|5|6|7| // +-+-+-+-+-+-+-+-+ // |F|NRI| Type | // +---------------+ outerNALUType := b[0] & 0x1F if outerNALUType <= NALUTypeAVCSingleMax { pkt.positionType = PositionTypeSingle return } else if outerNALUType == NALUTypeAVCFUA { // rfc3984 5.8. Fragmentation Units (FUs) // // 0 1 2 3 // 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 // +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ // | FU indicator | FU header | | // +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | // | | // | FU payload | // | | // | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ // | :...OPTIONAL RTP padding | // +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ // // FU indicator: // +---------------+ // |0|1|2|3|4|5|6|7| // +-+-+-+-+-+-+-+-+ // |F|NRI| Type | // +---------------+ // // Fu header: // +---------------+ // |0|1|2|3|4|5|6|7| // +-+-+-+-+-+-+-+-+ // |S|E|R| Type | // +---------------+ fuIndicator := b[0] _ = fuIndicator fuHeader := b[1] startCode := (fuHeader & 0x80) != 0 endCode := (fuHeader & 0x40) != 0 if startCode { pkt.positionType = PositionTypeFUAStart return } if endCode { pkt.positionType = PositionTypeFUAEnd return } pkt.positionType = PositionTypeFUAMiddle return } else if outerNALUType == NALUTypeAVCSTAPA { pkt.positionType = PositionTypeSTAPA } else { nazalog.Errorf("unknown nalu type. outerNALUType=%d", outerNALUType) } return } // AVC或HEVC格式的流，尝试合成一个完整的帧 func (r *RTPUnpacker) unpackOneAVCOrHEVC() bool { first := r.list.head.next if first == nil { return false } switch first.packet.positionType { case PositionTypeSingle: var pkt base.AVPacket pkt.PayloadType = r.payloadType pkt.Timestamp = first.packet.Header.Timestamp / uint32(r.clockRate/1000) pkt.Payload = make([]byte, len(first.packet.Raw)-int(first.packet.Header.payloadOffset)+4) bele.BEPutUint32(pkt.Payload, uint32(len(first.packet.Raw))-first.packet.Header.payloadOffset) copy(pkt.Payload[4:], first.packet.Raw[first.packet.Header.payloadOffset:]) r.unpackedFlag = true r.unpackedSeq = first.packet.Header.Seq r.list.head.next = first.next r.list.size-- r.onAVPacket(pkt) return true case PositionTypeSTAPA: var pkt base.AVPacket pkt.PayloadType = r.payloadType pkt.Timestamp = first.packet.Header.Timestamp / uint32(r.clockRate/1000) // 跳过首字节，并且将多nalu前的2字节长度，替换成4字节长度 buf := first.packet.Raw[first.packet.Header.payloadOffset+1:] // 使用两次遍历，第一次遍历找出总大小，第二次逐个拷贝，目的是使得内存块一次就申请好，不用动态扩容造成额外性能开销 totalSize := 0 for i := 0; i != len(buf); { if len(buf)-i < 2 { nazalog.Errorf("invalid STAP-A packet.") return false } naluSize := int(bele.BEUint16(buf[i:])) totalSize += 4 + naluSize i += 2 + naluSize } pkt.Payload = make([]byte, totalSize) j := 0 for i := 0; i != len(buf); { naluSize := int(bele.BEUint16(buf[i:])) bele.BEPutUint32(pkt.Payload[j:], uint32(naluSize)) copy(pkt.Payload[j+4:], buf[i+2:i+2+naluSize]) j += 4 + naluSize i += 2 + naluSize } r.unpackedFlag = true r.unpackedSeq = first.packet.Header.Seq r.list.head.next = first.next r.list.size-- r.onAVPacket(pkt) return true case PositionTypeFUAStart: prev := first p := first.next for { if prev == nil || p == nil { return false } if SubSeq(p.packet.Header.Seq, prev.packet.Header.Seq) != 1 { return false } if p.packet.positionType == PositionTypeFUAMiddle { prev = p p = p.next continue } else if p.packet.positionType == PositionTypeFUAEnd { var pkt base.AVPacket pkt.PayloadType = r.payloadType pkt.Timestamp = p.packet.Header.Timestamp / uint32(r.clockRate/1000) var naluTypeLen int var naluType []byte if r.payloadType == base.AVPacketPTAVC { naluTypeLen = 1 naluType = make([]byte, naluTypeLen) fuIndicator := first.packet.Raw[first.packet.Header.payloadOffset] fuHeader := first.packet.Raw[first.packet.Header.payloadOffset+1] naluType[0] = (fuIndicator & 0xE0) | (fuHeader & 0x1F) } else { naluTypeLen = 2 naluType = make([]byte, naluTypeLen) buf := first.packet.Raw[first.packet.Header.payloadOffset:] fuType := buf[2] & 0x3f naluType[0] = (buf[0] & 0x81) | (fuType << 1) naluType[1] = buf[1] } // 使用两次遍历，第一次遍历找出总大小，第二次逐个拷贝，目的是使得内存块一次就申请好，不用动态扩容造成额外性能开销 totalSize := 0 pp := first for { totalSize += len(pp.packet.Raw) - int(pp.packet.Header.payloadOffset) - (naluTypeLen + 1) if pp == p { break } pp = pp.next } pkt.Payload = make([]byte, totalSize+4+naluTypeLen) bele.BEPutUint32(pkt.Payload, uint32(totalSize+naluTypeLen)) var index int if r.payloadType == base.AVPacketPTAVC { pkt.Payload[4] = naluType[0] index = 5 } else { pkt.Payload[4] = naluType[0] pkt.Payload[5] = naluType[1] index = 6 } packetCount := 0 pp = first for { copy(pkt.Payload[index:], pp.packet.Raw[int(pp.packet.Header.payloadOffset)+(naluTypeLen+1):]) index += len(pp.packet.Raw) - int(pp.packet.Header.payloadOffset) - (naluTypeLen + 1) packetCount++ if pp == p { break } pp = pp.next } r.unpackedFlag = true r.unpackedSeq = p.packet.Header.Seq r.list.head.next = p.next r.list.size -= packetCount r.onAVPacket(pkt) return true } else { // 不应该出现其他类型 nazalog.Errorf("invalid position type. position=%d", p.packet.positionType) return false } } case PositionTypeFUAMiddle: // noop case PositionTypeFUAEnd: // noop default: nazalog.Errorf("invalid position. pos=%d", first.packet.positionType) } return false }