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Commit 9093339b authored by Juliusz Chroboczek's avatar Juliusz Chroboczek
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Rework handling of buffered keyframes. 

Instead of buffering the last keyframe, we merely keep track of its
seqno, and use the main cache for recovering.  We also send the whole
sequence of packets rather than just the keyframe itself.
parent f4aa86a4
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Showing with 35 additions and 282 deletions
packetcache/packetcache.go
View file @ 9093339b
......@@ -38,13 +38,6 @@ type bitmap struct {
bitmap uint32
}
// frame is used for storing the last keyframe
type frame struct {
timestamp uint32
complete bool
entries []entry
}
type Cache struct {
mu sync.Mutex
//stats
......@@ -55,10 +48,11 @@ type Cache struct {
totalExpected uint32
received uint32
totalReceived uint32
// last seen keyframe
keyframe uint16
keyframeValid bool
// bitmap
bitmap bitmap
// buffered keyframe
keyframe frame
// the actual cache
tail uint16
entries []entry
......@@ -162,94 +156,6 @@ func (bitmap *bitmap) get(next uint16) (bool, uint16, uint16) {
return true, first, uint16(bm >> 1)
}
// insert inserts a packet into a frame.
func (frame *frame) insert(seqno uint16, timestamp uint32, marker bool, data []byte) bool {
n := len(frame.entries)
i := 0
if n == 0 || seqno > frame.entries[n-1].seqno {
// fast path
i = n
} else {
for i < n {
if frame.entries[i].seqno >= seqno {
break
}
i++
}
if i < n && frame.entries[i].seqno == seqno {
// duplicate
return false
}
}
if n >= maxFrame {
// overflow
return false
}
lam := uint16(len(data))
if marker {
lam |= 0x8000
}
e := entry{
seqno: seqno,
lengthAndMarker: lam,
timestamp: timestamp,
}
copy(e.buf[:], data)
if i >= n {
frame.entries = append(frame.entries, e)
return true
}
frame.entries = append(frame.entries, entry{})
copy(frame.entries[i+1:], frame.entries[i:])
frame.entries[i] = e
return true
}
// store checks whether a packet is part of the current keyframe and, if
// so, inserts it.
func (frame *frame) store(seqno uint16, timestamp uint32, first bool, marker bool, data []byte) bool {
if first {
if frame.timestamp != timestamp {
frame.timestamp = timestamp
frame.complete = false
frame.entries = frame.entries[:0]
}
} else if len(frame.entries) > 0 {
if frame.timestamp != timestamp {
delta := seqno - frame.entries[0].seqno
if (delta&0x8000) == 0 && delta > 0x4000 {
frame.complete = false
frame.entries = frame.entries[:0]
}
return false
}
} else {
return false
}
done := frame.insert(seqno, timestamp, marker, data)
if done && !frame.complete {
marker := false
fst := frame.entries[0].seqno
for i := 1; i < len(frame.entries); i++ {
if frame.entries[i].seqno != fst+uint16(i) {
return done
}
if frame.entries[i].marker() {
marker = true
}
}
if marker {
frame.complete = true
}
}
return done
}
// Store stores a packet in the cache. It returns the first seqno in the
// bitmap, and the index at which the packet was stored.
func (cache *Cache) Store(seqno uint16, timestamp uint32, keyframe bool, marker bool, buf []byte) (uint16, uint16) {
......@@ -270,6 +176,10 @@ func (cache *Cache) Store(seqno uint16, timestamp uint32, keyframe bool, marker
cache.cycle++
}
cache.last = seqno
if cache.keyframeValid &&
compare(cache.keyframe, seqno) > 0 {
cache.keyframeValid = false
}
} else if cmp > 0 {
if cache.received < cache.expected {
cache.received++
......@@ -278,9 +188,9 @@ func (cache *Cache) Store(seqno uint16, timestamp uint32, keyframe bool, marker
}
cache.bitmap.set(seqno)
done := cache.keyframe.store(seqno, timestamp, keyframe, marker, buf)
if done && !cache.keyframe.complete {
completeKeyframe(cache)
if keyframe {
cache.keyframe = seqno
cache.keyframeValid = true
}
i := cache.tail
......@@ -297,58 +207,6 @@ func (cache *Cache) Store(seqno uint16, timestamp uint32, keyframe bool, marker
return cache.bitmap.first, i
}
// completeKeyFrame attempts to complete the current keyframe.
func completeKeyframe(cache *Cache) {
l := len(cache.keyframe.entries)
if l == 0 {
return
}
first := cache.keyframe.entries[0].seqno
last := cache.keyframe.entries[l-1].seqno
count := (last - first) // may wrap around
if count > 0x4000 {
// this shouldn't happen
return
}
var buf []byte
if count > 1 {
if buf == nil {
buf = make([]byte, BufSize)
}
for i := uint16(1); i < count; i++ {
n, ts, marker := get(first+i, cache.entries, buf)
if n > 0 {
cache.keyframe.store(
first+i, ts, false, marker, buf,
)
}
}
}
if !cache.keyframe.complete {
// Try to find packets after the last one.
for {
l := len(cache.keyframe.entries)
if cache.keyframe.entries[l-1].marker() {
break
}
if buf == nil {
buf = make([]byte, BufSize)
}
seqno := cache.keyframe.entries[l-1].seqno + 1
n, ts, marker := get(seqno, cache.entries, buf)
if n <= 0 {
break
}
done := cache.keyframe.store(
seqno, ts, false, marker, buf,
)
if !done || marker {
break
}
}
}
}
// Expect records that we expect n additional packets.
func (cache *Cache) Expect(n int) {
if n <= 0 {
......@@ -384,12 +242,7 @@ func (cache *Cache) Get(seqno uint16, result []byte) uint16 {
cache.mu.Lock()
defer cache.mu.Unlock()
n, _, _ := get(seqno, cache.keyframe.entries, result)
if n > 0 {
return n
}
n, _, _ = get(seqno, cache.entries, result)
n, _, _ := get(seqno, cache.entries, result)
if n > 0 {
return n
}
......@@ -397,17 +250,13 @@ func (cache *Cache) Get(seqno uint16, result []byte) uint16 {
return 0
}
func (cache *Cache) Last() (bool, uint16, uint32) {
func (cache *Cache) Last() (uint16, bool) {
cache.mu.Lock()
defer cache.mu.Unlock()
if !cache.lastValid {
return false, 0, 0
return 0, false
}
len, ts, _ := get(cache.last, cache.entries, nil)
if len == 0 {
return false, 0, 0
}
return true, cache.last, ts
return cache.last, true
}
// GetAt retrieves a packet from the cache assuming it is at the given index.
......@@ -427,32 +276,15 @@ func (cache *Cache) GetAt(seqno uint16, index uint16, result []byte) uint16 {
)
}
// Keyframe returns the last buffered keyframe. It returns the frame's
// timestamp and a boolean indicating if the frame is complete.
func (cache *Cache) Keyframe() (uint32, bool, []uint16) {
// Keyframe returns the seqno of the last seen keyframe
func (cache *Cache) Keyframe() (uint16, bool) {
cache.mu.Lock()
defer cache.mu.Unlock()
if len(cache.keyframe.entries) == 0 {
return 0, false, nil
if !cache.keyframeValid {
return 0, false
}
seqnos := make([]uint16, len(cache.keyframe.entries))
for i := range cache.keyframe.entries {
seqnos[i] = cache.keyframe.entries[i].seqno
}
return cache.keyframe.timestamp, cache.keyframe.complete, seqnos
}
func (cache *Cache) KeyframeSeqno() (bool, uint16, uint32) {
cache.mu.Lock()
defer cache.mu.Unlock()
if len(cache.keyframe.entries) == 0 {
return false, 0, 0
}
return true, cache.keyframe.entries[0].seqno, cache.keyframe.timestamp
return cache.keyframe, true
}
func (cache *Cache) resize(capacity int) {
......
packetcache/packetcache_test.go
View file @ 9093339b
......@@ -22,7 +22,7 @@ func TestCache(t *testing.T) {
buf2 := randomBuf()
cache := New(16)
found, _, _ := cache.Last()
_, found := cache.Last()
if found {
t.Errorf("Found in empty cache")
}
......@@ -30,13 +30,12 @@ func TestCache(t *testing.T) {
_, i1 := cache.Store(13, 42, false, false, buf1)
_, i2 := cache.Store(17, 42, false, false, buf2)
found, seqno, ts := cache.Last()
seqno, found := cache.Last()
if !found {
t.Errorf("Not found")
}
if seqno != 17 || ts != 42 {
t.Errorf("Expected %v, %v, got %v, %v",
17, 42, seqno, ts)
if seqno != 17 {
t.Errorf("Expected %v, got %v", 17, seqno)
}
buf := make([]byte, BufSize)
......@@ -170,84 +169,6 @@ func TestCacheGrowCond(t *testing.T) {
}
}
func TestKeyframe(t *testing.T) {
cache := New(16)
packet := make([]byte, 1)
buf := make([]byte, BufSize)
found, _, _ := cache.KeyframeSeqno()
if found {
t.Errorf("Found keyframe in empty cache")
}
cache.Store(7, 57, true, false, packet)
if cache.keyframe.complete {
t.Errorf("Expected false, got true")
}
cache.Store(8, 57, false, true, packet)
if !cache.keyframe.complete {
t.Errorf("Expected true, got false")
}
ts, c, kf := cache.Keyframe()
if ts != 57 || !c || len(kf) != 2 {
t.Errorf("Got %v %v %v, expected %v %v", ts, c, len(kf), 57, 2)
}
found, seqno, ts := cache.KeyframeSeqno()
if !found || seqno != 7 || ts != 57 {
t.Errorf("Got %v %v %v, expected %v %v", found, seqno, ts, 7, 57)
}
for _, i := range kf {
l := cache.Get(i, buf)
if int(l) != len(packet) {
t.Errorf("Couldn't get %v", i)
}
}
for i := 0; i < 32; i++ {
cache.Store(uint16(9+i), uint32(58+i), false, false, packet)
}
ts, c, kf = cache.Keyframe()
if ts != 57 || !c || len(kf) != 2 {
t.Errorf("Got %v %v %v, expected %v %v", ts, c, len(kf), 57, 2)
}
for _, i := range kf {
l := cache.Get(i, buf)
if int(l) != len(packet) {
t.Errorf("Couldn't get %v", i)
}
}
}
func TestKeyframeUnsorted(t *testing.T) {
cache := New(16)
packet := make([]byte, 1)
cache.Store(7, 57, false, false, packet)
cache.Store(9, 57, false, false, packet)
cache.Store(10, 57, false, true, packet)
cache.Store(6, 57, true, false, packet)
_, c, kf := cache.Keyframe()
if len(kf) != 2 || c {
t.Errorf("Got %v %v, expected 2", c, kf)
}
cache.Store(8, 57, false, false, packet)
_, c, kf = cache.Keyframe()
if len(kf) != 5 || !c {
t.Errorf("Got %v %v, expected 5", c, kf)
}
for i, v := range kf {
if v != uint16(i+6) {
t.Errorf("Position %v, expected %v, got %v\n",
i, i+6, v)
}
}
}
func TestBitmap(t *testing.T) {
value := uint64(0xcdd58f1e035379c0)
packet := make([]byte, 1)
......
rtpconn/rtpwriter.go
View file @ 9093339b
......@@ -206,9 +206,10 @@ func (writer *rtpWriter) add(track conn.DownTrack, add bool, max int) error {
}
}
func sendKeyframe(kf []uint16, track conn.DownTrack, cache *packetcache.Cache) {
func sendSequence(kf, last uint16, track conn.DownTrack, cache *packetcache.Cache) {
buf := make([]byte, packetcache.BufSize)
for _, seqno := range kf {
seqno := kf
for ((last - seqno) & 0x8000) == 0 {
bytes := cache.Get(seqno, buf)
if bytes == 0 {
return
......@@ -218,6 +219,7 @@ func sendKeyframe(kf []uint16, track conn.DownTrack, cache *packetcache.Cache) {
if err != nil {
return
}
seqno++
}
}
......@@ -253,14 +255,12 @@ func rtpWriterLoop(writer *rtpWriter, track *rtpUpTrack) {
action.track.SetCname(cname)
}
found, _, lts := track.cache.Last()
kts, _, kf := track.cache.Keyframe()
if found && len(kf) > 0 {
if ((lts-kts)&0x80000000) != 0 ||
lts-kts < 2*90000 {
// we got a recent keyframe
go sendKeyframe(
kf,
last, foundLast := track.cache.Last()
kf, foundKf := track.cache.Keyframe()
if foundLast && foundKf {
if last-kf < 40 { // modulo 2^16
go sendSequence(
kf, last,
action.track,
track.cache,
)
......@@ -331,11 +331,11 @@ func nackWriter(track *rtpUpTrack) {
// drop any nacks before the last keyframe
var cutoff uint16
found, seqno, _ := track.cache.KeyframeSeqno()
seqno, found := track.cache.Keyframe()
if found {
cutoff = seqno
} else {
last, lastSeqno, _ := track.cache.Last()
lastSeqno, last := track.cache.Last()
if !last {
// NACK on a fresh track? Give up.
return
......
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