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Implement pid and mark rewriting for VP9, fix VP9 sync bits. 

The sync bits were incorrect.  In addition, we need to set the
marker at the new end of the frame when doing spatial decimation.
This commit is contained in:
Juliusz Chroboczek 2021-08-03 05:05:21 +02:00
parent 56226a2934
commit 4f7be19644
3 changed files with 109 additions and 17 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

53
codecs/codecs.go
View File

@ -230,12 +230,15 @@ func KeyframeDimensions(codec string, packet *rtp.Packet) (uint32, uint32) {
type Flags struct {
Seqno uint16
Marker bool
Start bool
Pid uint16 // only if it needs rewriting
End bool
Keyframe bool
Pid uint16
Tid uint8
Sid uint8
TidUpSync bool
SidSync bool
SidUpSync bool
SidNonReference bool
Discardable bool
}
@ -248,6 +251,7 @@ func PacketFlags(codec string, buf []byte) (Flags, error) {
var flags Flags
flags.Seqno = (uint16(buf[2]) << 8) | uint16(buf[3])
flags.Marker = (buf[1] & 0x80) != 0
if strings.EqualFold(codec, "video/vp8") {
var packet rtp.Packet
@ -261,10 +265,13 @@ func PacketFlags(codec string, buf []byte) (Flags, error) {
return flags, err
}
flags.Start = vp8.S == 1 && vp8.PID == 0
flags.Start = vp8.S != 0 && vp8.PID == 0
flags.End = packet.Marker
flags.Keyframe = vp8.S != 0 && (vp8.Payload[0]&0x1) == 0
flags.Pid = vp8.PictureID
flags.Tid = vp8.TID
flags.TidUpSync = vp8.Y == 1
flags.TidUpSync = flags.Keyframe || vp8.Y == 1
flags.SidUpSync = flags.Keyframe
flags.Discardable = vp8.N == 1
return flags, nil
} else if strings.EqualFold(codec, "video/vp9") {
@ -279,22 +286,35 @@ func PacketFlags(codec string, buf []byte) (Flags, error) {
return flags, err
}
flags.Start = vp9.B
flags.End = vp9.E
if (vp9.Payload[0] & 0xc0) == 0x80 {
profile := (vp9.Payload[0] >> 4) & 0x3
if profile != 3 {
flags.Keyframe = (vp9.Payload[0] & 0xC) == 0
} else {
flags.Keyframe = (vp9.Payload[0] & 0x6) == 0
}
}
flags.Pid = vp9.PictureID
flags.Tid = vp9.TID
flags.Sid = vp9.SID
flags.TidUpSync = vp9.U
flags.SidSync = vp9.P
// not yet in pion/rtp
flags.TidUpSync = flags.Keyframe || vp9.U
flags.SidUpSync = flags.Keyframe || !vp9.P
flags.SidNonReference = (packet.Payload[0] & 0x01) != 0
return flags, nil
}
return flags, nil
}
func RewritePacket(codec string, data []byte, seqno uint16, delta uint16) error {
func RewritePacket(codec string, data []byte, setMarker bool, seqno uint16, delta uint16) error {
if len(data) < 12 {
return errTruncated
}
if(setMarker) {
data[1] |= 0x80
}
data[2] = uint8(seqno >> 8)
data[3] = uint8(seqno)
if delta == 0 {
@ -335,6 +355,23 @@ func RewritePacket(codec string, data []byte, seqno uint16, delta uint16) error
data[offset+2] = (data[offset+2] + uint8(delta)) & 0x7F
}
return nil
} else if strings.EqualFold(codec, "video/vp9") {
i := (data[offset] & 0x80) != 0
if !i {
return nil
}
m := (data[offset+1] & 0x80) != 0
if m {
pid := (uint16(data[offset+1]&0x7F) << 8) |
uint16(data[offset+2])
pid = (pid + delta) & 0x7FFF
data[offset+1] = 0x80 | byte((pid>>8)&0x7F)
data[offset+2] = byte(pid & 0xFF)
} else {
data[offset+1] = (data[offset+1] + uint8(delta)) & 0x7F
}
return nil
}
return errUnsupportedCodec
}

47
codecs/codecs_test.go
View File

@ -138,7 +138,7 @@ var vp8 = []byte{
0, 0, 0, 0,
}
func TestPacketFlags(t *testing.T) {
func TestPacketFlagsVP8(t *testing.T) {
buf := append([]byte{}, vp8...)
flags, err := PacketFlags("video/vp8", buf)
if flags.Seqno != 42 || !flags.Start || flags.Pid != 57 ||
@ -151,17 +151,56 @@ func TestPacketFlags(t *testing.T) {
}
}
func TestRewrite(t *testing.T) {
func TestRewriteVP8(t *testing.T) {
for i := uint16(0); i < 0x7fff; i++ {
buf := append([]byte{}, vp8...)
err := RewritePacket("video/vp8", buf, i, i)
err := RewritePacket("video/vp8", buf, true, i, i)
if err != nil {
t.Errorf("rewrite: %v", err)
continue
}
flags, err := PacketFlags("video/vp8", buf)
if err != nil || flags.Seqno != i ||
flags.Pid != (57+i)&0x7FFF {
flags.Pid != (57+i)&0x7FFF || !flags.Marker {
t.Errorf("Expected %v %v, got %v %v (%v)",
i, (57+i)&0x7FFF,
flags.Seqno, flags.Pid, err)
}
}
}
var vp9 = []byte{
0x80, 0, 0, 42,
0, 0, 0, 0,
0, 0, 0, 0,
0x88, 0x80, 57, 0,
}
func TestPacketFlagsVP9(t *testing.T) {
buf := append([]byte{}, vp9...)
flags, err := PacketFlags("video/vp9", buf)
if flags.Seqno != 42 || !flags.Start || flags.Pid != 57 ||
flags.Sid != 0 || flags.Tid != 0 ||
flags.TidUpSync || flags.Discardable || err != nil {
t.Errorf("Got %v, %v, %v, %v, %v, %v (%v)",
flags.Seqno, flags.Start, flags.Pid, flags.Sid,
flags.TidUpSync, flags.Discardable, err,
)
}
}
func TestRewriteVP9(t *testing.T) {
for i := uint16(0); i < 0x7fff; i++ {
buf := append([]byte{}, vp9...)
err := RewritePacket("video/vp9", buf, true, i, i)
if err != nil {
t.Errorf("rewrite: %v", err)
continue
}
flags, err := PacketFlags("video/vp9", buf)
if err != nil || flags.Seqno != i ||
flags.Pid != (57+i)&0x7FFF || !flags.Marker {
t.Errorf("Expected %v %v, got %v %v (%v)",
i, (57+i)&0x7FFF,
flags.Seqno, flags.Pid, err)

26
rtpconn/rtpconn.go
View File

@ -248,9 +248,23 @@ func (down *rtpDownTrack) Write(buf []byte) (int, error) {
}
if flags.Start && (layer.sid != layer.wantedSid) {
if flags.SidSync {
layer.sid = layer.wantedSid
down.setLayerInfo(layer)
if layer.wantedSid < layer.sid {
if flags.Keyframe {
layer.sid = layer.wantedSid
down.setLayerInfo(layer)
} else {
down.remote.RequestKeyframe()
}
} else if layer.wantedSid > layer.sid {
if flags.Keyframe {
layer.sid = layer.wantedSid
down.setLayerInfo(layer)
} else if flags.SidUpSync {
layer.sid = layer.sid + 1
down.setLayerInfo(layer)
} else {
down.remote.RequestKeyframe()
}
}
}
@ -267,7 +281,9 @@ func (down *rtpDownTrack) Write(buf []byte) (int, error) {
return 0, nil
}
if newseqno == flags.Seqno && piddelta == 0 {
setMarker := flags.Sid == layer.sid && flags.End && !flags.Marker
if !setMarker && newseqno == flags.Seqno && piddelta == 0 {
return down.write(buf)
}
@ -276,7 +292,7 @@ func (down *rtpDownTrack) Write(buf []byte) (int, error) {
buf2 := ibuf2.([]byte)
n := copy(buf2, buf)
err = codecs.RewritePacket(codec, buf2[:n], newseqno, piddelta)
err = codecs.RewritePacket(codec, buf2[:n], setMarker, newseqno, piddelta)
if err != nil {
return 0, err
}