fix(egress): 1s keyframe interval so YouTube Live leaves "Preparing" reliably

2s helped but YouTube was still intermittently stuck on "Preparing"
(Twitch always went live on the same stream). Drop the egress keyframe
interval to 1s (keyframe every 30 frames) — well within YouTube's <=4s
requirement and makes it go live consistently. Server-side; applies on
the next egress start.

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

Author: ralyodio

apps/web/src/app/api/stream/egress/start/route.ts

@@ -84,18 +84,19 @@ export async function POST(request: Request) {
       { stream: new StreamOutput({ protocol: StreamProtocol.RTMP, urls: rtmpUrls }) },
       {
         layout: 'speaker',
-        // Explicit 1080p30 (matches the H264_1080P_30 preset) but with a
-        // 2-second keyframe interval. The preset defaults to 4s, which YouTube
-        // Live rejects — the broadcast sits on "Preparing stream" with
-        // "excellent" health forever while Twitch (more lenient) goes live.
-        // YouTube requires a keyframe at least every 4s; 2s is the safe value.
+        // Explicit 1080p30 with a 1-second keyframe interval. The preset
+        // defaults to 4s; YouTube Live then sits on "Preparing stream" with
+        // good health and intermittently never goes live, while Twitch (more
+        // lenient) always does. 2s helped but YouTube was still flaky; 1s
+        // (a keyframe every 30 frames) makes YouTube leave "Preparing"
+        // reliably and is well within its <=4s requirement.
         encodingOptions: new EncodingOptions({
           width: 1920,
           height: 1080,
           framerate: 30,
           videoBitrate: 4500,
           audioBitrate: 128,
-          keyFrameInterval: 2,
+          keyFrameInterval: 1,
         }),
       }
     );