From 2130980d17bd7d45fc344a55154d66d559e1a756 Mon Sep 17 00:00:00 2001
From: Raja Subramanian <raja.gobi@tutanota.com>
Date: Fri, 11 Apr 2025 13:07:47 +0530
Subject: [PATCH] Add basic video support to WHIP. (#3602)

Tested with eyevinn client.

There are a few issues to figure out still
1. Simulcast - how?
2. For simulcast, how to know width, height so that adaptive stream can
   work.
3. The layer added is dummy. It works, but connection quality scoring
   would be incorrect (will always say excellent) without bitrate.

Will need some dynamic update of `TrackInfo` based on actual stream for
all of this to fit well into our system, but the simple video support
works for now.
---
 pkg/rtc/participant.go | 28 +++++++++++++++++++++++-----
 1 file changed, 23 insertions(+), 5 deletions(-)

diff --git a/pkg/rtc/participant.go b/pkg/rtc/participant.go
index b20f9464c..da9d46fef 100644
--- a/pkg/rtc/participant.go
+++ b/pkg/rtc/participant.go
@@ -858,8 +858,7 @@ func (p *ParticipantImpl) synthesizeAddTrackRequests(offer webrtc.SessionDescrip
 	}
 
 	for _, m := range parsed.MediaDescriptions {
-		if !strings.EqualFold(m.MediaName.Media, "audio") {
-			// ONE-SHOT-SIGNALLING-MODE-TODO: support video
+		if !strings.EqualFold(m.MediaName.Media, "audio") && !strings.EqualFold(m.MediaName.Media, "video") {
 			continue
 		}
 
@@ -886,15 +885,34 @@ func (p *ParticipantImpl) synthesizeAddTrackRequests(offer webrtc.SessionDescrip
 			trackID = guid.New(utils.TrackPrefix)
 		}
 
+		var (
+			name        string
+			trackSource livekit.TrackSource
+			trackType   livekit.TrackType
+		)
+		if strings.EqualFold(m.MediaName.Media, "audio") {
+			name = "synthesized-microphone"
+			trackSource = livekit.TrackSource_MICROPHONE
+			trackType = livekit.TrackType_AUDIO
+		} else {
+			name = "synthesized-camera"
+			trackSource = livekit.TrackSource_CAMERA
+			trackType = livekit.TrackType_VIDEO
+		}
 		req := &livekit.AddTrackRequest{
 			Cid:        trackID,
-			Name:       "synthesized-microphone",
-			Source:     livekit.TrackSource_MICROPHONE,
-			Type:       livekit.TrackType_AUDIO,
+			Name:       name,
+			Source:     trackSource,
+			Type:       trackType,
 			DisableDtx: true,
 			Stereo:     false,
 			Stream:     "camera",
 		}
+		// ONE-SHOT-SIGNALLING-MODE-TODO: support video simulcast
+		if strings.EqualFold(m.MediaName.Media, "video") {
+			// dummy layer to ensure at least one layer is available
+			req.Layers = []*livekit.VideoLayer{{}}
+		}
 		p.AddTrack(req)
 	}
 	return nil