playback: support concatenating segments with long gaps

Thanks to the new mtxi MP4 box, it's possible to check whether two
segments are consecutive without involving dates or timestamps.

When the new mtxi box is present in both segments, skip checking
whether the end of the first segment corresponds to the start of the
second segment.
This commit is contained in:
aler9 2025-11-09 19:58:06 +01:00
parent 7750e2beae
commit 40ab3c0dce
2 changed files with 380 additions and 29 deletions

View file

@ -58,38 +58,22 @@ func findMtxi(userData []amp4.IBox) *recordstore.Mtxi {
return nil
}
func segmentFMP4AreConsecutive(init1 *fmp4.Init, init2 *fmp4.Init) bool {
mtxi1 := findMtxi(init1.UserData)
mtxi2 := findMtxi(init2.UserData)
switch {
case mtxi1 == nil && mtxi2 != nil:
func segmentFMP4TracksAreEqual(tracks1 []*fmp4.InitTrack, tracks2 []*fmp4.InitTrack) bool {
if len(tracks1) != len(tracks2) {
return false
}
case mtxi1 != nil && mtxi2 == nil:
return false
for i, track1 := range tracks1 {
track2 := tracks2[i]
case mtxi1 == nil && mtxi2 == nil: // legacy method: compare tracks
if len(init1.Tracks) != len(init2.Tracks) {
if track1.ID != track2.ID ||
track1.TimeScale != track2.TimeScale ||
reflect.TypeOf(track1.Codec) != reflect.TypeOf(track2.Codec) {
return false
}
for i, track1 := range init1.Tracks {
track2 := init2.Tracks[i]
if track1.ID != track2.ID ||
track1.TimeScale != track2.TimeScale ||
reflect.TypeOf(track1.Codec) != reflect.TypeOf(track2.Codec) {
return false
}
}
return true
default:
return bytes.Equal(mtxi1.StreamID[:], mtxi2.StreamID[:]) &&
(mtxi1.SegmentNumber+1) == mtxi2.SegmentNumber
}
return true
}
func segmentFMP4CanBeConcatenated(
@ -98,9 +82,25 @@ func segmentFMP4CanBeConcatenated(
curInit *fmp4.Init,
curStart time.Time,
) bool {
return segmentFMP4AreConsecutive(prevInit, curInit) &&
!curStart.Before(prevEnd.Add(-concatenationTolerance)) &&
!curStart.After(prevEnd.Add(concatenationTolerance))
mtxi1 := findMtxi(prevInit.UserData)
mtxi2 := findMtxi(curInit.UserData)
switch {
case mtxi1 == nil && mtxi2 != nil:
return false
case mtxi1 != nil && mtxi2 == nil:
return false
case mtxi1 == nil && mtxi2 == nil: // legacy method
return segmentFMP4TracksAreEqual(prevInit.Tracks, curInit.Tracks) &&
!curStart.Before(prevEnd.Add(-concatenationTolerance)) &&
!curStart.After(prevEnd.Add(concatenationTolerance))
default:
return bytes.Equal(mtxi1.StreamID[:], mtxi2.StreamID[:]) &&
(mtxi1.SegmentNumber+1) == mtxi2.SegmentNumber
}
}
func segmentFMP4ReadHeader(r io.ReadSeeker) (*fmp4.Init, time.Duration, error) {

View file

@ -4,11 +4,15 @@ import (
"io"
"os"
"testing"
"time"
amp4 "github.com/abema/go-mp4"
"github.com/bluenviron/mediacommon/v2/pkg/codecs/mpeg4audio"
"github.com/bluenviron/mediacommon/v2/pkg/formats/fmp4"
"github.com/bluenviron/mediacommon/v2/pkg/formats/mp4"
"github.com/bluenviron/mediamtx/internal/recordstore"
"github.com/bluenviron/mediamtx/internal/test"
"github.com/stretchr/testify/require"
)
func writeBenchInit(f io.WriteSeeker) {
@ -74,3 +78,350 @@ func BenchmarkFMP4ReadHeader(b *testing.B) {
}()
}
}
func TestSegmentFMP4CanBeConcatenated(t *testing.T) {
baseTime := time.Date(2024, 1, 1, 0, 0, 0, 0, time.UTC)
streamID1 := [16]byte{1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16}
streamID2 := [16]byte{1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 17}
baseTracks := []*fmp4.InitTrack{
{
ID: 1,
TimeScale: 90000,
Codec: &mp4.CodecH264{
SPS: test.FormatH264.SPS,
PPS: test.FormatH264.PPS,
},
},
{
ID: 2,
TimeScale: 48000,
Codec: &mp4.CodecMPEG4Audio{
Config: mpeg4audio.AudioSpecificConfig{
Type: mpeg4audio.ObjectTypeAACLC,
SampleRate: 48000,
ChannelCount: 2,
},
},
},
}
differentTracks := []*fmp4.InitTrack{
{
ID: 1,
TimeScale: 90000,
Codec: &mp4.CodecH264{
SPS: test.FormatH264.SPS,
PPS: test.FormatH264.PPS,
},
},
}
for _, tt := range []struct {
name string
prevInit *fmp4.Init
prevEnd time.Time
curInit *fmp4.Init
curStart time.Time
want bool
}{
{
name: "with mtxi - consecutive segments, same stream",
prevInit: &fmp4.Init{
Tracks: baseTracks,
UserData: []amp4.IBox{
&recordstore.Mtxi{
StreamID: streamID1,
SegmentNumber: 1,
},
},
},
prevEnd: baseTime,
curInit: &fmp4.Init{
Tracks: baseTracks,
UserData: []amp4.IBox{
&recordstore.Mtxi{
StreamID: streamID1,
SegmentNumber: 2,
},
},
},
curStart: baseTime.Add(5 * time.Second),
want: true,
},
{
name: "with mtxi - non-consecutive segments, same stream",
prevInit: &fmp4.Init{
Tracks: baseTracks,
UserData: []amp4.IBox{
&recordstore.Mtxi{
StreamID: streamID1,
SegmentNumber: 1,
},
},
},
prevEnd: baseTime,
curInit: &fmp4.Init{
Tracks: baseTracks,
UserData: []amp4.IBox{
&recordstore.Mtxi{
StreamID: streamID1,
SegmentNumber: 3,
},
},
},
curStart: baseTime.Add(5 * time.Second),
want: false,
},
{
name: "with mtxi - consecutive segments, different streams",
prevInit: &fmp4.Init{
Tracks: baseTracks,
UserData: []amp4.IBox{
&recordstore.Mtxi{
StreamID: streamID1,
SegmentNumber: 1,
},
},
},
prevEnd: baseTime,
curInit: &fmp4.Init{
Tracks: baseTracks,
UserData: []amp4.IBox{
&recordstore.Mtxi{
StreamID: streamID2,
SegmentNumber: 2,
},
},
},
curStart: baseTime.Add(5 * time.Second),
want: false,
},
{
name: "prev has mtxi, current does not",
prevInit: &fmp4.Init{
Tracks: baseTracks,
UserData: []amp4.IBox{
&recordstore.Mtxi{
StreamID: streamID1,
SegmentNumber: 1,
},
},
},
prevEnd: baseTime,
curInit: &fmp4.Init{
Tracks: baseTracks,
UserData: []amp4.IBox{},
},
curStart: baseTime.Add(5 * time.Second),
want: false,
},
{
name: "prev does not have mtxi, current has mtxi",
prevInit: &fmp4.Init{
Tracks: baseTracks,
UserData: []amp4.IBox{},
},
prevEnd: baseTime,
curInit: &fmp4.Init{
Tracks: baseTracks,
UserData: []amp4.IBox{
&recordstore.Mtxi{
StreamID: streamID1,
SegmentNumber: 1,
},
},
},
curStart: baseTime.Add(5 * time.Second),
want: false,
},
{
name: "legacy mode - same tracks, within time tolerance",
prevInit: &fmp4.Init{
Tracks: baseTracks,
UserData: []amp4.IBox{},
},
prevEnd: baseTime.Add(10 * time.Second),
curInit: &fmp4.Init{
Tracks: baseTracks,
UserData: []amp4.IBox{},
},
curStart: baseTime.Add(10 * time.Second),
want: true,
},
{
name: "legacy mode - same tracks, exactly at tolerance boundary (before)",
prevInit: &fmp4.Init{
Tracks: baseTracks,
UserData: []amp4.IBox{},
},
prevEnd: baseTime.Add(10 * time.Second),
curInit: &fmp4.Init{
Tracks: baseTracks,
UserData: []amp4.IBox{},
},
curStart: baseTime.Add(9 * time.Second),
want: true,
},
{
name: "legacy mode - same tracks, exactly at tolerance boundary (after)",
prevInit: &fmp4.Init{
Tracks: baseTracks,
UserData: []amp4.IBox{},
},
prevEnd: baseTime.Add(10 * time.Second),
curInit: &fmp4.Init{
Tracks: baseTracks,
UserData: []amp4.IBox{},
},
curStart: baseTime.Add(11 * time.Second),
want: true,
},
{
name: "legacy mode - same tracks, outside time tolerance (too early)",
prevInit: &fmp4.Init{
Tracks: baseTracks,
UserData: []amp4.IBox{},
},
prevEnd: baseTime.Add(10 * time.Second),
curInit: &fmp4.Init{
Tracks: baseTracks,
UserData: []amp4.IBox{},
},
curStart: baseTime.Add(8*time.Second + 999*time.Millisecond),
want: false,
},
{
name: "legacy mode - same tracks, outside time tolerance (too late)",
prevInit: &fmp4.Init{
Tracks: baseTracks,
UserData: []amp4.IBox{},
},
prevEnd: baseTime.Add(10 * time.Second),
curInit: &fmp4.Init{
Tracks: baseTracks,
UserData: []amp4.IBox{},
},
curStart: baseTime.Add(11*time.Second + 1*time.Millisecond),
want: false,
},
{
name: "legacy mode - different number of tracks",
prevInit: &fmp4.Init{
Tracks: baseTracks,
UserData: []amp4.IBox{},
},
prevEnd: baseTime,
curInit: &fmp4.Init{
Tracks: differentTracks,
UserData: []amp4.IBox{},
},
curStart: baseTime.Add(5 * time.Second),
want: false,
},
{
name: "legacy mode - different track IDs",
prevInit: &fmp4.Init{
Tracks: []*fmp4.InitTrack{
{
ID: 1,
TimeScale: 90000,
Codec: &mp4.CodecH264{
SPS: test.FormatH264.SPS,
PPS: test.FormatH264.PPS,
},
},
},
UserData: []amp4.IBox{},
},
prevEnd: baseTime,
curInit: &fmp4.Init{
Tracks: []*fmp4.InitTrack{
{
ID: 2,
TimeScale: 90000,
Codec: &mp4.CodecH264{
SPS: test.FormatH264.SPS,
PPS: test.FormatH264.PPS,
},
},
},
UserData: []amp4.IBox{},
},
curStart: baseTime.Add(5 * time.Second),
want: false,
},
{
name: "legacy mode - different time scales",
prevInit: &fmp4.Init{
Tracks: []*fmp4.InitTrack{
{
ID: 1,
TimeScale: 90000,
Codec: &mp4.CodecH264{
SPS: test.FormatH264.SPS,
PPS: test.FormatH264.PPS,
},
},
},
UserData: []amp4.IBox{},
},
prevEnd: baseTime,
curInit: &fmp4.Init{
Tracks: []*fmp4.InitTrack{
{
ID: 1,
TimeScale: 48000,
Codec: &mp4.CodecH264{
SPS: test.FormatH264.SPS,
PPS: test.FormatH264.PPS,
},
},
},
UserData: []amp4.IBox{},
},
curStart: baseTime.Add(5 * time.Second),
want: false,
},
{
name: "legacy mode - different codec types",
prevInit: &fmp4.Init{
Tracks: []*fmp4.InitTrack{
{
ID: 1,
TimeScale: 90000,
Codec: &mp4.CodecH264{
SPS: test.FormatH264.SPS,
PPS: test.FormatH264.PPS,
},
},
},
UserData: []amp4.IBox{},
},
prevEnd: baseTime,
curInit: &fmp4.Init{
Tracks: []*fmp4.InitTrack{
{
ID: 1,
TimeScale: 90000,
Codec: &mp4.CodecMPEG4Audio{
Config: mpeg4audio.AudioSpecificConfig{
Type: mpeg4audio.ObjectTypeAACLC,
SampleRate: 48000,
ChannelCount: 2,
},
},
},
},
UserData: []amp4.IBox{},
},
curStart: baseTime.Add(5 * time.Second),
want: false,
},
} {
t.Run(tt.name, func(t *testing.T) {
got := segmentFMP4CanBeConcatenated(tt.prevInit, tt.prevEnd, tt.curInit, tt.curStart)
require.Equal(t, tt.want, got)
})
}
}