mirror of
https://github.com/jech/galene.git
synced 2024-11-23 09:05:59 +01:00
361 lines
8 KiB
Go
361 lines
8 KiB
Go
package codecs
|
|
|
|
import (
|
|
"errors"
|
|
"strings"
|
|
|
|
"github.com/pion/rtp"
|
|
"github.com/pion/rtp/codecs"
|
|
)
|
|
|
|
var errTruncated = errors.New("truncated packet")
|
|
var errUnsupportedCodec = errors.New("unsupported codec")
|
|
|
|
// Keyframe determines if packet is the start of a keyframe.
|
|
// It returns (true, true) if that is the case, (false, true) if that is
|
|
// definitely not the case, and (false, false) if the information cannot
|
|
// be determined.
|
|
func Keyframe(codec string, packet *rtp.Packet) (bool, bool) {
|
|
if strings.EqualFold(codec, "video/vp8") {
|
|
var vp8 codecs.VP8Packet
|
|
_, err := vp8.Unmarshal(packet.Payload)
|
|
if err != nil || len(vp8.Payload) < 1 {
|
|
return false, false
|
|
}
|
|
|
|
if vp8.S != 0 && vp8.PID == 0 && (vp8.Payload[0]&0x1) == 0 {
|
|
return true, true
|
|
}
|
|
return false, true
|
|
} else if strings.EqualFold(codec, "video/vp9") {
|
|
var vp9 codecs.VP9Packet
|
|
_, err := vp9.Unmarshal(packet.Payload)
|
|
if err != nil || len(vp9.Payload) < 1 {
|
|
return false, false
|
|
}
|
|
if !vp9.B {
|
|
return false, true
|
|
}
|
|
|
|
if (vp9.Payload[0] & 0xc0) != 0x80 {
|
|
return false, false
|
|
}
|
|
|
|
profile := (vp9.Payload[0] >> 4) & 0x3
|
|
if profile != 3 {
|
|
return (vp9.Payload[0] & 0xC) == 0, true
|
|
}
|
|
return (vp9.Payload[0] & 0x6) == 0, true
|
|
} else if strings.EqualFold(codec, "video/av1x") {
|
|
if len(packet.Payload) < 2 {
|
|
return false, true
|
|
}
|
|
// Z=0, N=1
|
|
if (packet.Payload[0] & 0x88) != 0x08 {
|
|
return false, true
|
|
}
|
|
w := (packet.Payload[0] & 0x30) >> 4
|
|
|
|
getObu := func(data []byte, last bool) ([]byte, int, bool) {
|
|
if last {
|
|
return data, len(data), false
|
|
}
|
|
offset := 0
|
|
length := 0
|
|
for {
|
|
if len(data) <= offset {
|
|
return nil, offset, offset > 0
|
|
}
|
|
l := data[offset]
|
|
length |= int(l&0x7f) << (offset * 7)
|
|
offset++
|
|
if (l & 0x80) == 0 {
|
|
break
|
|
}
|
|
}
|
|
if len(data) < offset+length {
|
|
return data[offset:], len(data), true
|
|
}
|
|
return data[offset : offset+length],
|
|
offset + length, false
|
|
}
|
|
offset := 1
|
|
i := 0
|
|
for {
|
|
obu, length, truncated :=
|
|
getObu(packet.Payload[offset:], int(w) == i+1)
|
|
if len(obu) < 1 {
|
|
return false, false
|
|
}
|
|
tpe := (obu[0] & 0x38) >> 3
|
|
switch i {
|
|
case 0:
|
|
// OBU_SEQUENCE_HEADER
|
|
if tpe != 1 {
|
|
return false, true
|
|
}
|
|
default:
|
|
// OBU_FRAME_HEADER or OBU_FRAME
|
|
if tpe == 3 || tpe == 6 {
|
|
if len(obu) < 2 {
|
|
return false, false
|
|
}
|
|
// show_existing_frame == 0
|
|
if (obu[1] & 0x80) != 0 {
|
|
return false, true
|
|
}
|
|
// frame_type == KEY_FRAME
|
|
return (obu[1] & 0x60) == 0, true
|
|
}
|
|
}
|
|
if truncated || i >= int(w) {
|
|
// the first frame header is in a second
|
|
// packet, give up.
|
|
return false, false
|
|
}
|
|
offset += length
|
|
i++
|
|
}
|
|
} else if strings.EqualFold(codec, "video/h264") {
|
|
if len(packet.Payload) < 1 {
|
|
return false, false
|
|
}
|
|
nalu := packet.Payload[0] & 0x1F
|
|
if nalu == 0 {
|
|
// reserved
|
|
return false, false
|
|
} else if nalu <= 23 {
|
|
// simple NALU
|
|
return nalu == 5, true
|
|
} else if nalu == 24 || nalu == 25 || nalu == 26 || nalu == 27 {
|
|
// STAP-A, STAP-B, MTAP16 or MTAP24
|
|
i := 1
|
|
if nalu == 25 || nalu == 26 || nalu == 27 {
|
|
// skip DON
|
|
i += 2
|
|
}
|
|
for i < len(packet.Payload) {
|
|
if i+2 > len(packet.Payload) {
|
|
return false, false
|
|
}
|
|
length := uint16(packet.Payload[i])<<8 |
|
|
uint16(packet.Payload[i+1])
|
|
i += 2
|
|
if i+int(length) > len(packet.Payload) {
|
|
return false, false
|
|
}
|
|
offset := 0
|
|
if nalu == 26 {
|
|
offset = 3
|
|
} else if nalu == 27 {
|
|
offset = 4
|
|
}
|
|
if offset >= int(length) {
|
|
return false, false
|
|
}
|
|
n := packet.Payload[i+offset] & 0x1F
|
|
if n == 7 {
|
|
return true, true
|
|
} else if n >= 24 {
|
|
// is this legal?
|
|
return false, false
|
|
}
|
|
i += int(length)
|
|
}
|
|
if i == len(packet.Payload) {
|
|
return false, true
|
|
}
|
|
return false, false
|
|
} else if nalu == 28 || nalu == 29 {
|
|
// FU-A or FU-B
|
|
if len(packet.Payload) < 2 {
|
|
return false, false
|
|
}
|
|
if (packet.Payload[1] & 0x80) == 0 {
|
|
// not a starting fragment
|
|
return false, true
|
|
}
|
|
return (packet.Payload[1]&0x1F == 7), true
|
|
}
|
|
return false, false
|
|
}
|
|
return false, false
|
|
}
|
|
|
|
func KeyframeDimensions(codec string, packet *rtp.Packet) (uint32, uint32) {
|
|
if strings.EqualFold(codec, "video/vp8") {
|
|
var vp8 codecs.VP8Packet
|
|
_, err := vp8.Unmarshal(packet.Payload)
|
|
if err != nil {
|
|
return 0, 0
|
|
}
|
|
if len(vp8.Payload) < 10 {
|
|
return 0, 0
|
|
}
|
|
raw := uint32(vp8.Payload[6]) | uint32(vp8.Payload[7])<<8 |
|
|
uint32(vp8.Payload[8])<<16 | uint32(vp8.Payload[9])<<24
|
|
width := raw & 0x3FFF
|
|
height := (raw >> 16) & 0x3FFF
|
|
return width, height
|
|
} else if strings.EqualFold(codec, "video/vp9") {
|
|
if packet == nil {
|
|
return 0, 0
|
|
}
|
|
var vp9 codecs.VP9Packet
|
|
_, err := vp9.Unmarshal(packet.Payload)
|
|
if err != nil {
|
|
return 0, 0
|
|
}
|
|
if !vp9.V {
|
|
return 0, 0
|
|
}
|
|
w := uint32(0)
|
|
h := uint32(0)
|
|
for i := range vp9.Width {
|
|
if i >= len(vp9.Height) {
|
|
break
|
|
}
|
|
if w < uint32(vp9.Width[i]) {
|
|
w = uint32(vp9.Width[i])
|
|
}
|
|
if h < uint32(vp9.Height[i]) {
|
|
h = uint32(vp9.Height[i])
|
|
}
|
|
}
|
|
return w, h
|
|
} else {
|
|
return 0, 0
|
|
}
|
|
}
|
|
|
|
type Flags struct {
|
|
Seqno uint16
|
|
Marker bool
|
|
Start bool
|
|
End bool
|
|
Keyframe bool
|
|
Pid uint16 // only returned for VP8
|
|
Tid uint8
|
|
Sid uint8
|
|
TidUpSync bool
|
|
SidUpSync bool
|
|
SidNonReference bool
|
|
Discardable bool
|
|
}
|
|
|
|
func PacketFlags(codec string, buf []byte) (Flags, error) {
|
|
if len(buf) < 12 {
|
|
return Flags{}, errTruncated
|
|
}
|
|
|
|
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
|
|
err := packet.Unmarshal(buf)
|
|
if err != nil {
|
|
return flags, err
|
|
}
|
|
var vp8 codecs.VP8Packet
|
|
_, err = vp8.Unmarshal(packet.Payload)
|
|
if err != nil {
|
|
return flags, err
|
|
}
|
|
|
|
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 = flags.Keyframe || vp8.Y == 1
|
|
flags.SidUpSync = flags.Keyframe
|
|
flags.Discardable = vp8.N == 1
|
|
return flags, nil
|
|
} else if strings.EqualFold(codec, "video/vp9") {
|
|
var packet rtp.Packet
|
|
err := packet.Unmarshal(buf)
|
|
if err != nil {
|
|
return flags, err
|
|
}
|
|
var vp9 codecs.VP9Packet
|
|
_, err = vp9.Unmarshal(packet.Payload)
|
|
if err != nil {
|
|
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.Tid = vp9.TID
|
|
flags.Sid = vp9.SID
|
|
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, 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 {
|
|
return nil
|
|
}
|
|
|
|
offset := 12
|
|
offset += int(data[0]&0x0F) * 4
|
|
if len(data) < offset+4 {
|
|
return errTruncated
|
|
}
|
|
|
|
if (data[0] & 0x10) != 0 {
|
|
length := uint16(data[offset+2])<<8 | uint16(data[offset+3])
|
|
offset += 4 + int(length)*4
|
|
if len(data) < offset+4 {
|
|
return errTruncated
|
|
}
|
|
}
|
|
|
|
// only rewrite PID for VP8.
|
|
if strings.EqualFold(codec, "video/vp8") {
|
|
x := (data[offset] & 0x80) != 0
|
|
if !x {
|
|
return nil
|
|
}
|
|
i := (data[offset+1] & 0x80) != 0
|
|
if !i {
|
|
return nil
|
|
}
|
|
m := (data[offset+2] & 0x80) != 0
|
|
if m {
|
|
pid := (uint16(data[offset+2]&0x7F) << 8) |
|
|
uint16(data[offset+3])
|
|
pid = (pid + delta) & 0x7FFF
|
|
data[offset+2] = 0x80 | byte((pid>>8)&0x7F)
|
|
data[offset+3] = byte(pid & 0xFF)
|
|
} else {
|
|
data[offset+2] = (data[offset+2] + uint8(delta)) & 0x7F
|
|
}
|
|
return nil
|
|
}
|
|
|
|
return nil
|
|
}
|