mirror of
https://github.com/jech/galene.git
synced 2024-12-22 23:35:46 +01:00
375 lines
8.2 KiB
Go
375 lines
8.2 KiB
Go
package codecs
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import (
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"errors"
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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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)
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var errTruncated = errors.New("truncated packet")
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// Keyframe 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 Keyframe(codec string, packet *rtp.Packet) (bool, bool) {
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if strings.EqualFold(codec, "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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} else if strings.EqualFold(codec, "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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} else if strings.EqualFold(codec, "video/av1") {
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if len(packet.Payload) < 2 {
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return false, true
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}
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// Z=0, N=1
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if (packet.Payload[0] & 0x88) != 0x08 {
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return false, true
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}
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w := (packet.Payload[0] & 0x30) >> 4
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getObu := func(data []byte, last bool) ([]byte, int, bool) {
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if last {
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return data, len(data), false
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}
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offset := 0
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length := 0
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for {
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if len(data) <= offset {
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return nil, offset, offset > 0
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}
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if offset >= 4 {
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return nil, offset, true
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}
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l := data[offset]
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length |= int(l&0x7f) << (offset * 7)
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offset++
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if (l & 0x80) == 0 {
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break
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}
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}
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if len(data) < offset+length {
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return data[offset:], len(data), true
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}
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return data[offset : offset+length],
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offset + length, false
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}
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offset := 1
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i := 0
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for {
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obu, length, truncated :=
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getObu(packet.Payload[offset:], int(w) == i+1)
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if len(obu) < 1 {
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return false, false
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}
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tpe := (obu[0] & 0x38) >> 3
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switch i {
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case 0:
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// OBU_SEQUENCE_HEADER
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if tpe != 1 {
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return false, true
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}
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default:
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// OBU_FRAME_HEADER or OBU_FRAME
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if tpe == 3 || tpe == 6 {
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if len(obu) < 2 {
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return false, false
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}
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// show_existing_frame == 0
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if (obu[1] & 0x80) != 0 {
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return false, true
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}
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// frame_type == KEY_FRAME
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return (obu[1] & 0x60) == 0, true
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}
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}
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if truncated || i >= int(w) {
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// the first frame header is in a second
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// packet, give up.
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return false, false
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}
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offset += length
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i++
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}
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} else if strings.EqualFold(codec, "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 == 7, 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 == 7 {
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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 == 7), true
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}
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return false, false
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}
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return false, false
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}
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func KeyframeDimensions(codec string, packet *rtp.Packet) (uint32, uint32) {
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if strings.EqualFold(codec, "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 {
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return 0, 0
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}
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if len(vp8.Payload) < 10 {
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return 0, 0
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}
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raw := uint32(vp8.Payload[6]) | uint32(vp8.Payload[7])<<8 |
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uint32(vp8.Payload[8])<<16 | uint32(vp8.Payload[9])<<24
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width := raw & 0x3FFF
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height := (raw >> 16) & 0x3FFF
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return width, height
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} else if strings.EqualFold(codec, "video/vp9") {
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if packet == nil {
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return 0, 0
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}
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var vp9 codecs.VP9Packet
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_, err := vp9.Unmarshal(packet.Payload)
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if err != nil {
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return 0, 0
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}
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if !vp9.V {
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return 0, 0
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}
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w := uint32(0)
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h := uint32(0)
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for i := range vp9.Width {
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if i >= len(vp9.Height) {
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break
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}
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if w < uint32(vp9.Width[i]) {
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w = uint32(vp9.Width[i])
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}
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if h < uint32(vp9.Height[i]) {
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h = uint32(vp9.Height[i])
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}
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}
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return w, h
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} else {
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return 0, 0
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}
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}
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type Flags struct {
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Seqno uint16
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Marker bool
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Start bool
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End bool
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Keyframe bool
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Pid uint16 // only returned for VP8
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Tid uint8
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Sid uint8
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TidUpSync bool
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SidUpSync bool
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SidNonReference bool
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Discardable bool
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}
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func PacketFlags(codec string, buf []byte) (Flags, error) {
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if len(buf) < 4 {
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return Flags{}, errTruncated
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}
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var flags Flags
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flags.Seqno = (uint16(buf[2]) << 8) | uint16(buf[3])
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flags.Marker = (buf[1] & 0x80) != 0
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if strings.EqualFold(codec, "video/vp8") {
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var packet rtp.Packet
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err := packet.Unmarshal(buf)
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if err != nil {
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return flags, err
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}
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var vp8 codecs.VP8Packet
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_, err = vp8.Unmarshal(packet.Payload)
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if err != nil {
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return flags, err
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}
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flags.Start = vp8.S != 0 && vp8.PID == 0
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flags.End = packet.Marker
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flags.Keyframe = vp8.S != 0 && vp8.PID == 0 &&
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len(vp8.Payload) > 0 && (vp8.Payload[0]&0x1) == 0
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flags.Pid = vp8.PictureID
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flags.Tid = vp8.TID
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flags.TidUpSync = flags.Keyframe || vp8.Y == 1
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flags.SidUpSync = flags.Keyframe
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flags.Discardable = vp8.N == 1
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return flags, nil
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} else if strings.EqualFold(codec, "video/vp9") {
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var packet rtp.Packet
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err := packet.Unmarshal(buf)
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if err != nil {
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return flags, err
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}
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var vp9 codecs.VP9Packet
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_, err = vp9.Unmarshal(packet.Payload)
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if err != nil {
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return flags, err
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}
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flags.Start = vp9.B
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flags.End = vp9.E
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if vp9.B && len(vp9.Payload) > 0 &&
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(vp9.Payload[0] & 0xc0) == 0x80 {
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profile := (vp9.Payload[0] >> 4) & 0x3
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if profile != 3 {
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flags.Keyframe = (vp9.Payload[0] & 0xC) == 0
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} else {
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flags.Keyframe = (vp9.Payload[0] & 0x6) == 0
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}
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}
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flags.Tid = vp9.TID
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flags.Sid = vp9.SID
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flags.TidUpSync = flags.Keyframe || vp9.U
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flags.SidUpSync = flags.Keyframe || !vp9.P
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flags.SidNonReference = (packet.Payload[0] & 0x01) != 0
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return flags, nil
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}
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return flags, nil
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}
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func RewritePacket(codec string, data []byte, setMarker bool, seqno uint16, delta uint16) error {
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if len(data) < 12 {
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return errTruncated
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}
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if setMarker {
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data[1] |= 0x80
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}
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data[2] = uint8(seqno >> 8)
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data[3] = uint8(seqno)
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if delta == 0 {
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return nil
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}
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offset := 12
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offset += int(data[0]&0x0F) * 4
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if len(data) <= offset {
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return errTruncated
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}
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if (data[0] & 0x10) != 0 {
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length := uint16(data[offset+2])<<8 | uint16(data[offset+3])
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offset += 4 + int(length)*4
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if len(data) < offset+4 {
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return errTruncated
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}
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}
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// only rewrite PID for VP8.
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if strings.EqualFold(codec, "video/vp8") {
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x := (data[offset] & 0x80) != 0
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if !x {
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return nil
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}
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offset++
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if len(data) <= offset {
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return errTruncated
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}
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i := (data[offset] & 0x80) != 0
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if !i {
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return nil
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}
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offset++
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if len(data) <= offset {
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return errTruncated
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}
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m := (data[offset] & 0x80) != 0
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if m {
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if len(data) <= offset+1 {
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return errTruncated
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}
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pid := (uint16(data[offset]&0x7F) << 8) |
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uint16(data[offset+1])
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pid = (pid + delta) & 0x7FFF
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data[offset] = 0x80 | byte((pid>>8)&0x7F)
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data[offset+1] = byte(pid & 0xFF)
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} else {
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data[offset] = (data[offset] + uint8(delta)) & 0x7F
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}
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return nil
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}
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return nil
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}
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