diff options
Diffstat (limited to 'vendor/github.com/pion/rtp/codecs/vp9_packet.go')
| -rw-r--r-- | vendor/github.com/pion/rtp/codecs/vp9_packet.go | 385 |
1 files changed, 385 insertions, 0 deletions
diff --git a/vendor/github.com/pion/rtp/codecs/vp9_packet.go b/vendor/github.com/pion/rtp/codecs/vp9_packet.go new file mode 100644 index 0000000..5cb619b --- /dev/null +++ b/vendor/github.com/pion/rtp/codecs/vp9_packet.go @@ -0,0 +1,385 @@ +package codecs + +import ( + "github.com/pion/randutil" +) + +// Use global random generator to properly seed by crypto grade random. +var globalMathRandomGenerator = randutil.NewMathRandomGenerator() // nolint:gochecknoglobals + +// VP9Payloader payloads VP9 packets +type VP9Payloader struct { + pictureID uint16 + initialized bool + + // InitialPictureIDFn is a function that returns random initial picture ID. + InitialPictureIDFn func() uint16 +} + +const ( + vp9HeaderSize = 3 // Flexible mode 15 bit picture ID + maxSpatialLayers = 5 + maxVP9RefPics = 3 +) + +// Payload fragments an VP9 packet across one or more byte arrays +func (p *VP9Payloader) Payload(mtu int, payload []byte) [][]byte { + /* + * https://www.ietf.org/id/draft-ietf-payload-vp9-10.txt + * + * Flexible mode (F=1) + * 0 1 2 3 4 5 6 7 + * +-+-+-+-+-+-+-+-+ + * |I|P|L|F|B|E|V|-| (REQUIRED) + * +-+-+-+-+-+-+-+-+ + * I: |M| PICTURE ID | (REQUIRED) + * +-+-+-+-+-+-+-+-+ + * M: | EXTENDED PID | (RECOMMENDED) + * +-+-+-+-+-+-+-+-+ + * L: | TID |U| SID |D| (CONDITIONALLY RECOMMENDED) + * +-+-+-+-+-+-+-+-+ -\ + * P,F: | P_DIFF |N| (CONDITIONALLY REQUIRED) - up to 3 times + * +-+-+-+-+-+-+-+-+ -/ + * V: | SS | + * | .. | + * +-+-+-+-+-+-+-+-+ + * + * Non-flexible mode (F=0) + * 0 1 2 3 4 5 6 7 + * +-+-+-+-+-+-+-+-+ + * |I|P|L|F|B|E|V|-| (REQUIRED) + * +-+-+-+-+-+-+-+-+ + * I: |M| PICTURE ID | (RECOMMENDED) + * +-+-+-+-+-+-+-+-+ + * M: | EXTENDED PID | (RECOMMENDED) + * +-+-+-+-+-+-+-+-+ + * L: | TID |U| SID |D| (CONDITIONALLY RECOMMENDED) + * +-+-+-+-+-+-+-+-+ + * | TL0PICIDX | (CONDITIONALLY REQUIRED) + * +-+-+-+-+-+-+-+-+ + * V: | SS | + * | .. | + * +-+-+-+-+-+-+-+-+ + */ + + if !p.initialized { + if p.InitialPictureIDFn == nil { + p.InitialPictureIDFn = func() uint16 { + return uint16(globalMathRandomGenerator.Intn(0x7FFF)) + } + } + p.pictureID = p.InitialPictureIDFn() & 0x7FFF + p.initialized = true + } + if payload == nil { + return [][]byte{} + } + + maxFragmentSize := mtu - vp9HeaderSize + payloadDataRemaining := len(payload) + payloadDataIndex := 0 + + if min(maxFragmentSize, payloadDataRemaining) <= 0 { + return [][]byte{} + } + + var payloads [][]byte + for payloadDataRemaining > 0 { + currentFragmentSize := min(maxFragmentSize, payloadDataRemaining) + out := make([]byte, vp9HeaderSize+currentFragmentSize) + + out[0] = 0x90 // F=1 I=1 + if payloadDataIndex == 0 { + out[0] |= 0x08 // B=1 + } + if payloadDataRemaining == currentFragmentSize { + out[0] |= 0x04 // E=1 + } + out[1] = byte(p.pictureID>>8) | 0x80 + out[2] = byte(p.pictureID) + copy(out[vp9HeaderSize:], payload[payloadDataIndex:payloadDataIndex+currentFragmentSize]) + payloads = append(payloads, out) + + payloadDataRemaining -= currentFragmentSize + payloadDataIndex += currentFragmentSize + } + p.pictureID++ + if p.pictureID >= 0x8000 { + p.pictureID = 0 + } + + return payloads +} + +// VP9Packet represents the VP9 header that is stored in the payload of an RTP Packet +type VP9Packet struct { + // Required header + I bool // PictureID is present + P bool // Inter-picture predicted frame + L bool // Layer indices is present + F bool // Flexible mode + B bool // Start of a frame + E bool // End of a frame + V bool // Scalability structure (SS) data present + + // Recommended headers + PictureID uint16 // 7 or 16 bits, picture ID + + // Conditionally recommended headers + TID uint8 // Temporal layer ID + U bool // Switching up point + SID uint8 // Spatial layer ID + D bool // Inter-layer dependency used + + // Conditionally required headers + PDiff []uint8 // Reference index (F=1) + TL0PICIDX uint8 // Temporal layer zero index (F=0) + + // Scalability structure headers + NS uint8 // N_S + 1 indicates the number of spatial layers present in the VP9 stream + Y bool // Each spatial layer's frame resolution present + G bool // PG description present flag. + NG uint8 // N_G indicates the number of pictures in a Picture Group (PG) + Width []uint16 + Height []uint16 + PGTID []uint8 // Temporal layer ID of pictures in a Picture Group + PGU []bool // Switching up point of pictures in a Picture Group + PGPDiff [][]uint8 // Reference indecies of pictures in a Picture Group + + Payload []byte +} + +// Unmarshal parses the passed byte slice and stores the result in the VP9Packet this method is called upon +func (p *VP9Packet) Unmarshal(packet []byte) ([]byte, error) { + if packet == nil { + return nil, errNilPacket + } + if len(packet) < 1 { + return nil, errShortPacket + } + + p.I = packet[0]&0x80 != 0 + p.P = packet[0]&0x40 != 0 + p.L = packet[0]&0x20 != 0 + p.F = packet[0]&0x10 != 0 + p.B = packet[0]&0x08 != 0 + p.E = packet[0]&0x04 != 0 + p.V = packet[0]&0x02 != 0 + + pos := 1 + var err error + + if p.I { + pos, err = p.parsePictureID(packet, pos) + if err != nil { + return nil, err + } + } + + if p.L { + pos, err = p.parseLayerInfo(packet, pos) + if err != nil { + return nil, err + } + } + + if p.F && p.P { + pos, err = p.parseRefIndices(packet, pos) + if err != nil { + return nil, err + } + } + + if p.V { + pos, err = p.parseSSData(packet, pos) + if err != nil { + return nil, err + } + } + + p.Payload = packet[pos:] + return p.Payload, nil +} + +// Picture ID: +// +// +-+-+-+-+-+-+-+-+ +// I: |M| PICTURE ID | M:0 => picture id is 7 bits. +// +-+-+-+-+-+-+-+-+ M:1 => picture id is 15 bits. +// M: | EXTENDED PID | +// +-+-+-+-+-+-+-+-+ +// +func (p *VP9Packet) parsePictureID(packet []byte, pos int) (int, error) { + if len(packet) <= pos { + return pos, errShortPacket + } + + p.PictureID = uint16(packet[pos] & 0x7F) + if packet[pos]&0x80 != 0 { + pos++ + if len(packet) <= pos { + return pos, errShortPacket + } + p.PictureID = p.PictureID<<8 | uint16(packet[pos]) + } + pos++ + return pos, nil +} + +func (p *VP9Packet) parseLayerInfo(packet []byte, pos int) (int, error) { + pos, err := p.parseLayerInfoCommon(packet, pos) + if err != nil { + return pos, err + } + + if p.F { + return pos, nil + } + + return p.parseLayerInfoNonFlexibleMode(packet, pos) +} + +// Layer indices (flexible mode): +// +// +-+-+-+-+-+-+-+-+ +// L: | T |U| S |D| +// +-+-+-+-+-+-+-+-+ +// +func (p *VP9Packet) parseLayerInfoCommon(packet []byte, pos int) (int, error) { + if len(packet) <= pos { + return pos, errShortPacket + } + + p.TID = packet[pos] >> 5 + p.U = packet[pos]&0x10 != 0 + p.SID = (packet[pos] >> 1) & 0x7 + p.D = packet[pos]&0x01 != 0 + + if p.SID >= maxSpatialLayers { + return pos, errTooManySpatialLayers + } + + pos++ + return pos, nil +} + +// Layer indices (non-flexible mode): +// +// +-+-+-+-+-+-+-+-+ +// L: | T |U| S |D| +// +-+-+-+-+-+-+-+-+ +// | TL0PICIDX | +// +-+-+-+-+-+-+-+-+ +// +func (p *VP9Packet) parseLayerInfoNonFlexibleMode(packet []byte, pos int) (int, error) { + if len(packet) <= pos { + return pos, errShortPacket + } + + p.TL0PICIDX = packet[pos] + pos++ + return pos, nil +} + +// Reference indices: +// +// +-+-+-+-+-+-+-+-+ P=1,F=1: At least one reference index +// P,F: | P_DIFF |N| up to 3 times has to be specified. +// +-+-+-+-+-+-+-+-+ N=1: An additional P_DIFF follows +// current P_DIFF. +// +func (p *VP9Packet) parseRefIndices(packet []byte, pos int) (int, error) { + for { + if len(packet) <= pos { + return pos, errShortPacket + } + p.PDiff = append(p.PDiff, packet[pos]>>1) + if packet[pos]&0x01 == 0 { + break + } + if len(p.PDiff) >= maxVP9RefPics { + return pos, errTooManyPDiff + } + pos++ + } + pos++ + + return pos, nil +} + +// Scalability structure (SS): +// +// +-+-+-+-+-+-+-+-+ +// V: | N_S |Y|G|-|-|-| +// +-+-+-+-+-+-+-+-+ -| +// Y: | WIDTH | (OPTIONAL) . +// + + . +// | | (OPTIONAL) . +// +-+-+-+-+-+-+-+-+ . N_S + 1 times +// | HEIGHT | (OPTIONAL) . +// + + . +// | | (OPTIONAL) . +// +-+-+-+-+-+-+-+-+ -| +// G: | N_G | (OPTIONAL) +// +-+-+-+-+-+-+-+-+ -| +// N_G: | T |U| R |-|-| (OPTIONAL) . +// +-+-+-+-+-+-+-+-+ -| . N_G times +// | P_DIFF | (OPTIONAL) . R times . +// +-+-+-+-+-+-+-+-+ -| -| +// +func (p *VP9Packet) parseSSData(packet []byte, pos int) (int, error) { + if len(packet) <= pos { + return pos, errShortPacket + } + + p.NS = packet[pos] >> 5 + p.Y = packet[pos]&0x10 != 0 + p.G = (packet[pos]>>1)&0x7 != 0 + pos++ + + NS := p.NS + 1 + p.NG = 0 + + if p.Y { + p.Width = make([]uint16, NS) + p.Height = make([]uint16, NS) + for i := 0; i < int(NS); i++ { + p.Width[i] = uint16(packet[pos])<<8 | uint16(packet[pos+1]) + pos += 2 + p.Height[i] = uint16(packet[pos])<<8 | uint16(packet[pos+1]) + pos += 2 + } + } + + if p.G { + p.NG = packet[pos] + pos++ + } + + for i := 0; i < int(p.NG); i++ { + p.PGTID = append(p.PGTID, packet[pos]>>5) + p.PGU = append(p.PGU, packet[pos]&0x10 != 0) + R := (packet[pos] >> 2) & 0x3 + pos++ + + p.PGPDiff = append(p.PGPDiff, []uint8{}) + for j := 0; j < int(R); j++ { + p.PGPDiff[i] = append(p.PGPDiff[i], packet[pos]) + pos++ + } + } + + return pos, nil +} + +// VP9PartitionHeadChecker checks VP9 partition head +type VP9PartitionHeadChecker struct{} + +// IsPartitionHead checks whether if this is a head of the VP9 partition +func (*VP9PartitionHeadChecker) IsPartitionHead(packet []byte) bool { + p := &VP9Packet{} + if _, err := p.Unmarshal(packet); err != nil { + return false + } + return p.B +} |