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lal/pkg/rtprtcp/rtp_unpacker_aac.go

84 lines
2.5 KiB
Go

// 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"
// AAC格式的流尝试合成一个完整的帧
func (r *RTPUnpacker) unpackOneAAC() bool {
first := r.list.head.next
if first == nil {
return false
}
// TODO chef:
// 2. 只处理了一个RTP包含多个音频包的情况没有处理一个音频包跨越多个RTP包的情况是否有这种情况
// rfc3640 2.11. Global Structure of Payload Format
//
// +---------+-----------+-----------+---------------+
// | RTP | AU Header | Auxiliary | Access Unit |
// | Header | Section | Section | Data Section |
// +---------+-----------+-----------+---------------+
//
// <----------RTP Packet Payload----------->
//
// rfc3640 3.2.1. The AU Header Section
//
// +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+- .. -+-+-+-+-+-+-+-+-+-+
// |AU-headers-length|AU-header|AU-header| |AU-header|padding|
// | | (1) | (2) | | (n) | bits |
// +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+- .. -+-+-+-+-+-+-+-+-+-+
//
// rfc3640 3.3.6. High Bit-rate AAC
//
b := first.packet.Raw[first.packet.Header.payloadOffset:]
//nazalog.Debugf("%d, %d, %s", len(pkt.Raw), pkt.Header.timestamp, hex.Dump(b))
// AU Header Section
var auHeaderLength uint32
auHeaderLength = uint32(b[0])<<8 + uint32(b[1])
auHeaderLength = (auHeaderLength + 7) / 8
//nazalog.Debugf("auHeaderLength=%d", auHeaderLength)
// no Auxiliary Section
pauh := uint32(2) // AU Header pos
pau := uint32(2) + auHeaderLength // AU pos
auNum := uint32(auHeaderLength) / 2
for i := uint32(0); i < auNum; i++ {
var auSize uint32
auSize = uint32(b[pauh])<<8 | uint32(b[pauh+1]&0xF8) // 13bit
auSize /= 8
//auIndex := b[pauh+1] & 0x7
// raw AAC frame
// pau, auSize
//nazalog.Debugf("%d %d %s", auSize, auIndex, hex.Dump(b[pau:pau+auSize]))
var outPkt base.AVPacket
outPkt.Timestamp = first.packet.Header.Timestamp / uint32(r.clockRate/1000)
outPkt.Timestamp += i * uint32((1024*1000)/r.clockRate)
outPkt.Payload = b[pau : pau+auSize]
outPkt.PayloadType = r.payloadType
r.onAVPacket(outPkt)
pauh += 2
pau += auSize
}
r.unpackedFlag = true
r.unpackedSeq = first.packet.Header.Seq
r.list.head.next = first.next
r.list.size--
return true
}