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Merge branch 'h264-rtp-lexer'

This commit is contained in:
Saxon 2019-06-07 02:00:41 +09:30
parent 499a26c09f ce457e1d95
commit 2640b1b615
4 changed files with 9 additions and 334 deletions
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193
codec/h264/lex.go
View File

@ -7,6 +7,7 @@ DESCRIPTION
AUTHOR
Dan Kortschak <dan@ausocean.org>
Saxon Nelson-Milton <saxon@ausocean.org>
LICENSE
lex.go is Copyright (C) 2017 the Australian Ocean Lab (AusOcean)
@ -25,45 +26,15 @@ LICENSE
along with revid in gpl.txt. If not, see http://www.gnu.org/licenses.
*/
// lex.go provides a lexer to lex h264 bytestream into access units.
// Package h264 provides a h264 bytestream lexer and RTP H264 access unit
// extracter.
package h264
import (
"bytes"
"encoding/binary"
"fmt"
"io"
"time"
"bitbucket.org/ausocean/av/codec/codecutil"
"bitbucket.org/ausocean/av/protocol/rtp"
)
// NAL types (from https://tools.ietf.org/html/rfc6184#page-13)
const (
// Single nal units bounds.
typeSingleNALULowBound = 1
typeSingleNALUHighBound = 23
// Single-time aggregation packets.
typeSTAPA = 24
typeSTAPB = 25
// Multi-time aggregation packets.
typeMTAP16 = 26
typeMTAP24 = 27
// Fragmentation packets.
typeFUA = 28
typeFUB = 29
)
// Min NAL lengths.
const (
minSingleNALLen = 1
minSTAPALen = 4
minFUALen = 2
)
var noDelay = make(chan time.Time)
@ -74,11 +45,11 @@ func init() {
var h264Prefix = [...]byte{0x00, 0x00, 0x01, 0x09, 0xf0}
// LexFromBytestream lexes H.264 NAL units read from src into separate writes
// Lex lexes H.264 NAL units read from src into separate writes
// to dst with successive writes being performed not earlier than the specified
// delay. NAL units are split after type 1 (Coded slice of a non-IDR picture), 5
// (Coded slice of a IDR picture) and 8 (Picture parameter set).
func LexFromBytestream(dst io.Writer, src io.Reader, delay time.Duration) error {
func Lex(dst io.Writer, src io.Reader, delay time.Duration) error {
var tick <-chan time.Time
if delay == 0 {
tick = noDelay
@ -163,157 +134,3 @@ outer:
_, err := dst.Write(buf)
return err
}
// Buffer sizes.
const (
maxAUSize = 100000 // Max access unit size in bytes.
maxRTPSize = 1500 // Max ethernet transmission unit in bytes.
)
// RTPLexer is a lexer for lexing H264 from RTP packets.
type RTPLexer struct {
buf *bytes.Buffer // Holds the current access unit.
frag bool // Indicates if we're currently dealing with a fragmentation packet.
}
// NewRTPLexer returns a new RTPLexer.
func NewRTPLexer() *RTPLexer {
return &RTPLexer{
buf: bytes.NewBuffer(make([]byte, 0, maxAUSize))}
}
// Lex extracts H264 access units from an RTP stream. This function
// expects that each read from src will provide a single RTP packet.
func (l *RTPLexer) Lex(dst io.Writer, src io.Reader, delay time.Duration) error {
buf := make([]byte, maxRTPSize)
for {
n, err := src.Read(buf)
switch err {
case nil: // Do nothing.
case io.EOF:
return nil
default:
return fmt.Errorf("source read error: %v\n", err)
}
// Get payload from RTP packet.
payload, err := rtp.Payload(buf[:n])
if err != nil {
return fmt.Errorf("could not get RTP payload, failed with err: %v\n", err)
}
nalType := payload[0] & 0x1f
// If not currently fragmented then we ignore current write.
if l.frag && nalType != typeFUA {
l.buf.Reset()
l.frag = false
continue
}
if typeSingleNALULowBound <= nalType && nalType <= typeSingleNALUHighBound {
// If len too small, ignore.
if len(payload) < minSingleNALLen {
continue
}
l.writeWithPrefix(payload)
} else {
switch nalType {
case typeSTAPA:
l.handleSTAPA(payload)
case typeFUA:
l.handleFUA(payload)
case typeSTAPB:
panic("STAP-B type unsupported")
case typeMTAP16:
panic("MTAP16 type unsupported")
case typeMTAP24:
panic("MTAP24 type unsupported")
case typeFUB:
panic("FU-B type unsupported")
default:
panic("unsupported type")
}
}
markerIsSet, err := rtp.Marker(buf[:n])
if err != nil {
return fmt.Errorf("could not get marker bit, failed with err: %v\n", err)
}
if markerIsSet {
l.buf.WriteTo(dst)
l.buf.Reset()
}
}
return nil
}
// handleSTAPA parses NAL units from an aggregation packet and writes
// them to the Lexers buffer buf.
func (l *RTPLexer) handleSTAPA(d []byte) {
// If the length is too small, ignore.
if len(d) < minSTAPALen {
return
}
for i := 1; i < len(d); {
size := int(binary.BigEndian.Uint16(d[i:]))
// Skip over NAL unit size.
const sizeOfFieldLen = 2
i += sizeOfFieldLen
// Get the NALU.
nalu := d[i : i+size]
i += size
l.writeWithPrefix(nalu)
}
}
// handleFUA parses NAL units from fragmentation packets and writes
// them to the Lexer's buf.
func (l *RTPLexer) handleFUA(d []byte) {
// If length is too small, ignore.
if len(d) < minFUALen {
return
}
// Get start and end indiciators from FU header.
const FUHeadIdx = 1
start := d[FUHeadIdx]&0x80 != 0
end := d[FUHeadIdx]&0x40 != 0
// If start, form new header, skip FU indicator only and set first byte to
// new header. Otherwise, skip over both FU indicator and FU header.
if start {
newHead := (d[0] & 0xe0) | (d[1] & 0x1f)
d = d[1:]
d[0] = newHead
if end {
panic("bad fragmentation packet")
}
l.frag = true
l.writeWithPrefix(d)
} else {
d = d[2:]
if end {
l.frag = false
}
l.writeNoPrefix(d)
}
}
// write writes a NAL unit to the Lexer's buf in byte stream format using the
// start code.
func (l *RTPLexer) writeWithPrefix(d []byte) {
const prefix = "\x00\x00\x00\x01"
l.buf.Write([]byte(prefix))
l.buf.Write(d)
}
// writeNoPrefix writes data to the Lexer's buf. This is used for non start
// fragmentations of a NALU.
func (l *RTPLexer) writeNoPrefix(d []byte) {
l.buf.Write(d)
}

142
codec/h264/lex_test.go
View File

@ -31,8 +31,6 @@ LICENSE
package h264
import (
"io"
"testing"
"time"
)
@ -223,143 +221,3 @@ func TestH264(t *testing.T) {
}
}
*/
// rtpReader provides an io.Reader for reading the test RTP stream.
type rtpReader struct {
packets [][]byte
idx int
}
// Read implements io.Reader.
func (r *rtpReader) Read(p []byte) (int, error) {
if r.idx == len(r.packets) {
return 0, io.EOF
}
b := r.packets[r.idx]
n := copy(p, b)
if n < len(r.packets[r.idx]) {
r.packets[r.idx] = r.packets[r.idx][n:]
} else {
r.idx++
}
return n, nil
}
// destination holds the access units extracted during the lexing process.
type destination [][]byte
// Write implements io.Writer.
func (d *destination) Write(p []byte) (int, error) {
tmp := make([]byte, len(p))
copy(tmp, p)
*d = append(*d, tmp)
return len(p), nil
}
// TestLex checks that the Lexer can correctly extract H264 access units from
// h264 RTP stream in RTP payload format.
func TestRTPLex(t *testing.T) {
const rtpVer = 2
tests := []struct {
packets [][]byte
expect [][]byte
}{
{
packets: [][]byte{
{ // Single NAL unit.
0x80, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, // RTP header.
typeSingleNALULowBound, // NAL header.
0x01, 0x02, 0x03, 0x04, // NAL Data.
},
{ // Fragmentation (start packet).
0x80, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, // RTP header.
typeFUA, // FU indicator.
0x80 | typeSingleNALULowBound, // FU header.
0x01, 0x02, 0x03, // FU payload.
},
{ // Fragmentation (middle packet)
0x80, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, // RTP header.
typeFUA, // NAL indicator.
typeSingleNALULowBound, // FU header.
0x04, 0x05, 0x06, // FU payload.
},
{ // Fragmentation (end packet)
0x80, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, // RTP header.
typeFUA, // NAL indicator.
0x40 | typeSingleNALULowBound, // FU header.
0x07, 0x08, 0x09, // FU payload
},
{ // Aggregation. Make last packet of access unit => marker bit true.
0x80, 0x80, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, // RTP header.
typeSTAPA, // NAL header.
0x00, 0x04, // NAL 1 size.
0x01, 0x02, 0x03, 0x04, // NAL 1 data.
0x00, 0x04, // NAL 2 size.
0x01, 0x02, 0x03, 0x04, // NAL 2 data.
},
// Second access unit.
{ // Single NAL unit.
0x80, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, // RTP header.
typeSingleNALULowBound, // NAL header.
0x01, 0x02, 0x03, 0x04, // NAL Data.
},
{ // Single NAL. Make last packet of access unit => marker bit true.
0x80, 0x80, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, // RTP header.
typeSingleNALULowBound, // NAL header.
0x01, 0x02, 0x03, 0x04, // NAL data.
},
},
expect: [][]byte{
// First access unit.
{
// NAL 1
0x00, 0x00, 0x00, 0x01, // Start code.
typeSingleNALULowBound, // NAL header.
0x01, 0x02, 0x03, 0x04, // NAL data.
// NAL 2
0x00, 0x00, 0x00, 0x01, // Start code.
typeSingleNALULowBound,
0x01, 0x02, 0x03, // FU payload.
0x04, 0x05, 0x06, // FU payload.
0x07, 0x08, 0x09, // FU payload.
// NAL 3
0x00, 0x00, 0x00, 0x01, // Start code.
0x01, 0x02, 0x03, 0x04, // NAL data.
// NAL 4
0x00, 0x00, 0x00, 0x01, // Start code.
0x01, 0x02, 0x03, 0x04, // NAL 2 data
},
// Second access unit.
{
// NAL 1
0x00, 0x00, 0x00, 0x01, // Start code.
typeSingleNALULowBound, // NAL header.
0x01, 0x02, 0x03, 0x04, // Data.
// NAL 2
0x00, 0x00, 0x00, 0x01, // Start code.
typeSingleNALULowBound, // NAL header.
0x01, 0x02, 0x03, 0x04, // Data.
},
},
},
}
for testNum, test := range tests {
r := &rtpReader{packets: test.packets}
d := &destination{}
err := NewRTPLexer().Lex(d, r, 0)
if err != nil {
t.Fatalf("error lexing: %v\n", err)
}
for i, accessUnit := range test.expect {
for j, part := range accessUnit {
if part != [][]byte(*d)[i][j] {
t.Fatalf("did not get expected data for test: %v.\nGot: %v\nWant: %v\n", testNum, d, test.expect)
}
}
}
}
}

4
protocol/rtmp/rtmp_test.go
View File

@ -199,7 +199,7 @@ func TestFromFrame(t *testing.T) {
if err != nil {
t.Errorf("Failed to create flv encoder with error: %v", err)
}
err = h264.LexFromBytestream(flvEncoder, bytes.NewReader(videoData), time.Second/time.Duration(frameRate))
err = h264.Lex(flvEncoder, bytes.NewReader(videoData), time.Second/time.Duration(frameRate))
if err != nil {
t.Errorf("Lexing failed with error: %v", err)
}
@ -251,7 +251,7 @@ func TestFromFile(t *testing.T) {
if err != nil {
t.Fatalf("failed to create encoder: %v", err)
}
err = h264.LexFromBytestream(flvEncoder, f, time.Second/time.Duration(25))
err = h264.Lex(flvEncoder, f, time.Second/time.Duration(25))
if err != nil {
t.Errorf("Lexing and encoding failed with error: %v", err)
}

4
revid/revid.go
View File

@ -280,10 +280,10 @@ func (r *Revid) setupPipeline(mtsEnc, flvEnc func(dst io.WriteCloser, rate int)
switch r.config.Input {
case Raspivid:
r.setupInput = r.startRaspivid
r.lexTo = h264.LexFromBytestream
r.lexTo = h264.Lex
case V4L:
r.setupInput = r.startV4L
r.lexTo = h264.LexFromBytestream
r.lexTo = h264.Lex
case File:
r.setupInput = r.setupInputForFile
case RTSP: