mirror of
https://github.com/jech/galene.git
synced 2024-12-23 07:45:46 +01:00
208 lines
4.6 KiB
Go
208 lines
4.6 KiB
Go
package rtpconn
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import (
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"io"
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"log"
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"strings"
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"github.com/pion/rtp"
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"github.com/pion/rtp/codecs"
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"github.com/pion/webrtc/v3"
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"github.com/jech/galene/packetcache"
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"github.com/jech/galene/rtptime"
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)
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// isKeyframe determines if packet is the start of a keyframe.
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// It returns (true, true) if that is the case, (false, true) if that is
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// definitely not the case, and (false, false) if the information cannot
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// be determined.
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func isKeyframe(codec string, packet *rtp.Packet) (bool, bool) {
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switch strings.ToLower(codec) {
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case "video/vp8":
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var vp8 codecs.VP8Packet
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_, err := vp8.Unmarshal(packet.Payload)
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if err != nil || len(vp8.Payload) < 1 {
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return false, false
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}
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if vp8.S != 0 && vp8.PID == 0 && (vp8.Payload[0]&0x1) == 0 {
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return true, true
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}
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return false, true
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case "video/vp9":
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var vp9 codecs.VP9Packet
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_, err := vp9.Unmarshal(packet.Payload)
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if err != nil || len(vp9.Payload) < 1 {
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return false, false
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}
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if !vp9.B {
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return false, true
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}
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if (vp9.Payload[0] & 0xc0) != 0x80 {
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return false, false
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}
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profile := (vp9.Payload[0] >> 4) & 0x3
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if profile != 3 {
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return (vp9.Payload[0] & 0xC) == 0, true
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}
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return (vp9.Payload[0] & 0x6) == 0, true
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case "video/h264":
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if len(packet.Payload) < 1 {
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return false, false
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}
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nalu := packet.Payload[0] & 0x1F
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if nalu == 0 {
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// reserved
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return false, false
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} else if nalu <= 23 {
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// simple NALU
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return nalu == 5, true
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} else if nalu == 24 || nalu == 25 || nalu == 26 || nalu == 27 {
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// STAP-A, STAP-B, MTAP16 or MTAP24
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i := 1
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if nalu == 25 || nalu == 26 || nalu == 27 {
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// skip DON
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i += 2
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}
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for i < len(packet.Payload) {
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if i+2 > len(packet.Payload) {
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return false, false
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}
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length := uint16(packet.Payload[i])<<8 |
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uint16(packet.Payload[i+1])
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i += 2
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if i+int(length) > len(packet.Payload) {
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return false, false
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}
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offset := 0
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if nalu == 26 {
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offset = 3
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} else if nalu == 27 {
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offset = 4
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}
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if offset >= int(length) {
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return false, false
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}
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n := packet.Payload[i + offset] & 0x1F
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if n == 5 {
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return true, true
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} else if n >= 24 {
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// is this legal?
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return false, false
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}
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i += int(length)
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}
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if i == len(packet.Payload) {
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return false, true
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}
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return false, false
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} else if nalu == 28 || nalu == 29 {
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// FU-A or FU-B
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if len(packet.Payload) < 2 {
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return false, false
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}
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if (packet.Payload[1] & 0x80) == 0 {
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// not a starting fragment
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return false, true
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}
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return (packet.Payload[1]&0x1F == 5), true
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}
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return false, false
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default:
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return false, false
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}
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}
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func readLoop(conn *rtpUpConnection, track *rtpUpTrack) {
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writers := rtpWriterPool{conn: conn, track: track}
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defer func() {
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writers.close()
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close(track.readerDone)
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}()
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isvideo := track.track.Kind() == webrtc.RTPCodecTypeVideo
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codec := track.track.Codec()
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sendNACK := track.hasRtcpFb("nack", "")
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buf := make([]byte, packetcache.BufSize)
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var packet rtp.Packet
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for {
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bytes, _, err := track.track.Read(buf)
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if err != nil {
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if err != io.EOF {
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log.Printf("%v", err)
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}
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break
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}
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track.rate.Accumulate(uint32(bytes))
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err = packet.Unmarshal(buf[:bytes])
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if err != nil {
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log.Printf("%v", err)
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continue
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}
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track.jitter.Accumulate(packet.Timestamp)
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kf, _ := isKeyframe(codec.MimeType, &packet)
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first, index := track.cache.Store(
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packet.SequenceNumber, packet.Timestamp,
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kf, packet.Marker, buf[:bytes],
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)
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_, rate := track.rate.Estimate()
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delta := packet.SequenceNumber - first
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if (delta & 0x8000) != 0 {
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delta = 0
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}
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// send a NACK if a packet is late by 20ms or 2 packets,
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// whichever is more. Since TCP sends a dupack after 2 packets,
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// this should be safe.
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packets := rate / 50
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if packets > 24 {
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packets = 24
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}
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if packets < 2 {
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packets = 2
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}
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// send NACKs for more recent packets, this makes better
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// use of the NACK bitmap
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unnacked := uint16(4)
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if unnacked > uint16(packets) {
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unnacked = uint16(packets)
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}
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if uint32(delta) > packets {
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found, first, bitmap := track.cache.BitmapGet(
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packet.SequenceNumber - unnacked,
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)
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if found && sendNACK {
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err := conn.sendNACK(track, first, bitmap)
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if err != nil {
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log.Printf("%v", err)
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}
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}
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}
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delay := uint32(rtptime.JiffiesPerSec / 1024)
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if rate > 512 {
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delay = rtptime.JiffiesPerSec / rate / 2
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}
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writers.write(packet.SequenceNumber, index, delay,
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isvideo, packet.Marker)
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select {
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case action := <-track.localCh:
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err := writers.add(action.track, action.add)
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if err != nil {
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log.Printf("add/remove track: %v", err)
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}
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default:
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}
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}
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}
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