From bd7dbcfcf244d548673efe6e8ecc0a3acc8d9a5a Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?C=C3=A9dric=20Verstraeten?= <cedric@verstraeten.io>
Date: Wed, 11 Feb 2026 15:11:52 +0000
Subject: [PATCH] Enhance FPS tracking and logging for keyframes in gortsplib
 and mp4 modules

---
 machinery/src/capture/gortsplib.go | 29 +++++++++++++++++++++--------
 machinery/src/video/mp4.go         |  5 +++++
 2 files changed, 26 insertions(+), 8 deletions(-)

diff --git a/machinery/src/capture/gortsplib.go b/machinery/src/capture/gortsplib.go
index aadc241..445ac23 100644
--- a/machinery/src/capture/gortsplib.go
+++ b/machinery/src/capture/gortsplib.go
@@ -637,10 +637,13 @@ func (g *Golibrtsp) Start(ctx context.Context, streamType string, queue *packets
 
 				// Frame is complete — update per-stream FPS from PTS.
 				if okPTS {
-					if ft := g.fpsTrackers[g.VideoH264Index]; ft != nil {
-						if ptsFPS := ft.update(pts); ptsFPS > 0 && ptsFPS <= 120 {
-							g.Streams[g.VideoH264Index].FPS = ptsFPS
-						}
+					ft := g.fpsTrackers[g.VideoH264Index]
+					if ft == nil {
+						ft = newFPSTracker(30)
+						g.fpsTrackers[g.VideoH264Index] = ft
+					}
+					if ptsFPS := ft.update(pts); ptsFPS > 0 && ptsFPS <= 120 {
+						g.Streams[g.VideoH264Index].FPS = ptsFPS
 					}
 				}
 
@@ -654,8 +657,10 @@ func (g *Golibrtsp) Start(ctx context.Context, streamType string, queue *packets
 				nonIDRPresent := false
 				idrPresent := false
 
+				var naluTypes []string
 				for _, nalu := range au {
 					typ := h264.NALUType(nalu[0] & 0x1F)
+					naluTypes = append(naluTypes, fmt.Sprintf("%s(%d,sz=%d)", typ.String(), int(typ), len(nalu)))
 					switch typ {
 					case h264.NALUTypeAccessUnitDelimiter:
 						continue
@@ -702,6 +707,11 @@ func (g *Golibrtsp) Start(ctx context.Context, streamType string, queue *packets
 					return
 				}
 
+				if idrPresent {
+					log.Log.Debug(fmt.Sprintf("capture.golibrtsp.Start(%s): IDR frame NALUs: [%s]",
+						streamType, fmt.Sprintf("%v", naluTypes)))
+				}
+
 				// Convert to packet.
 				enc, err := h264.AnnexBMarshal(filteredAU)
 				if err != nil {
@@ -817,10 +827,13 @@ func (g *Golibrtsp) Start(ctx context.Context, streamType string, queue *packets
 
 				// Frame is complete — update per-stream FPS from PTS.
 				if okPTS {
-					if ft := g.fpsTrackers[g.VideoH265Index]; ft != nil {
-						if ptsFPS := ft.update(pts); ptsFPS > 0 && ptsFPS <= 120 {
-							g.Streams[g.VideoH265Index].FPS = ptsFPS
-						}
+					ft := g.fpsTrackers[g.VideoH265Index]
+					if ft == nil {
+						ft = newFPSTracker(30)
+						g.fpsTrackers[g.VideoH265Index] = ft
+					}
+					if ptsFPS := ft.update(pts); ptsFPS > 0 && ptsFPS <= 120 {
+						g.Streams[g.VideoH265Index].FPS = ptsFPS
 					}
 				}
 
diff --git a/machinery/src/video/mp4.go b/machinery/src/video/mp4.go
index ac245e5..745eddf 100644
--- a/machinery/src/video/mp4.go
+++ b/machinery/src/video/mp4.go
@@ -189,6 +189,11 @@ func (mp4 *MP4) flushPendingVideoSample(nextPTS uint64) bool {
 
 func (mp4 *MP4) AddSampleToTrack(trackID uint32, isKeyframe bool, data []byte, pts uint64) error {
 
+	if isKeyframe && trackID == uint32(mp4.VideoTrack) {
+		log.Log.Debug(fmt.Sprintf("mp4.AddSampleToTrack(): KEYFRAME received - track=%d, PTS=%d, size=%d, sampleCount=%d",
+			trackID, pts, len(data), mp4.SampleCount))
+	}
+
 	if isKeyframe {
 
 		// Determine whether to start a new fragment.