fix(video): force h264 and trace frame pipeline

crates/wzp-video/src/mediacodec.rs

@@ -160,8 +160,11 @@ impl VideoEncoder for MediaCodecEncoder {
         if packet.is_empty() {
             return false;
         }
-        let nal_type = packet[0] & 0x1F;
-        nal_type == 5
+        let nals = split_annex_b(packet);
+        if nals.is_empty() {
+            return (packet[0] & 0x1F) == 5;
+        }
+        nals.iter().any(|nal| !nal.is_empty() && (nal[0] & 0x1F) == 5)
     }
 }
 
@@ -1135,6 +1138,11 @@ mod tests {
         };
         assert!(enc.is_keyframe(&[0x65, 0x01]));
         assert!(!enc.is_keyframe(&[0x41, 0x01]));
+        assert!(enc.is_keyframe(&[
+            0x00, 0x00, 0x00, 0x01, 0x67, 0x01, // SPS
+            0x00, 0x00, 0x00, 0x01, 0x68, 0x02, // PPS
+            0x00, 0x00, 0x00, 0x01, 0x65, 0x03, // IDR
+        ]));
     }
 
     #[test]

crates/wzp-video/src/videotoolbox.rs

@@ -160,9 +160,11 @@ impl VideoEncoder for VideoToolboxEncoder {
         if packet.is_empty() {
             return false;
         }
-        let nal_type = packet[0] & 0x1F;
-        // NAL type 5 = IDR slice (keyframe).
-        nal_type == 5
+        let nals = split_annex_b(packet);
+        if nals.is_empty() {
+            return (packet[0] & 0x1F) == 5;
+        }
+        nals.iter().any(|nal| !nal.is_empty() && (nal[0] & 0x1F) == 5)
     }
 }
 
@@ -791,6 +793,11 @@ mod tests {
         let enc = VideoToolboxEncoder::new(1280, 720, 2_000_000).unwrap();
         assert!(enc.is_keyframe(&[0x65, 0x01, 0x02]));
         assert!(!enc.is_keyframe(&[0x41, 0x01, 0x02]));
+        assert!(enc.is_keyframe(&[
+            0x00, 0x00, 0x00, 0x01, 0x67, 0x01, // SPS
+            0x00, 0x00, 0x00, 0x01, 0x68, 0x02, // PPS
+            0x00, 0x00, 0x00, 0x01, 0x65, 0x03, // IDR
+        ]));
     }
 
     #[test]

crates/wzp-video/tests/pipeline_roundtrip.rs

@@ -177,9 +177,9 @@ fn missing_fragment_blocks_reassembly() {
 #[test]
 fn video_codec_selection_semantics() {
     // The relay's selection rule is: first codec offered by the caller.
-    let offered = vec![CodecId::Av1Main, CodecId::H264Baseline, CodecId::H265Main];
+    let offered = vec![CodecId::H264Baseline];
     let chosen = offered.into_iter().next();
-    assert_eq!(chosen, Some(CodecId::Av1Main));
+    assert_eq!(chosen, Some(CodecId::H264Baseline));
 
     // When no codecs are offered, video is audio-only.
     let empty: Vec<CodecId> = vec![];