From 6b98f067c4d791a3c1892003120a2cb21837bf2e Mon Sep 17 00:00:00 2001
From: Brad Stein <Brad.Stein@gmail.com>
Date: Tue, 19 May 2026 13:09:08 -0300
Subject: [PATCH] fix: reject MJPEG during HEVC UVC handoff

---
 Cargo.lock                                     |  6 +++---
 client/Cargo.toml                              |  2 +-
 common/Cargo.toml                              |  2 +-
 server/Cargo.toml                              |  2 +-
 server/src/video_sinks/webcam_sink.rs          |  1 +
 .../src/video_sinks/webcam_sink/constructor.rs |  2 ++
 .../video_sinks/webcam_sink/frame_handoff.rs   | 18 +++++++++++++++++-
 7 files changed, 26 insertions(+), 7 deletions(-)

diff --git a/Cargo.lock b/Cargo.lock
index 3bcf692..a8285e8 100644
--- a/Cargo.lock
+++ b/Cargo.lock
@@ -1658,7 +1658,7 @@ checksum = "09edd9e8b54e49e587e4f6295a7d29c3ea94d469cb40ab8ca70b288248a81db2"
 
 [[package]]
 name = "lesavka_client"
-version = "0.26.1"
+version = "0.26.2"
 dependencies = [
  "anyhow",
  "async-stream",
@@ -1692,7 +1692,7 @@ dependencies = [
 
 [[package]]
 name = "lesavka_common"
-version = "0.26.1"
+version = "0.26.2"
 dependencies = [
  "anyhow",
  "base64",
@@ -1704,7 +1704,7 @@ dependencies = [
 
 [[package]]
 name = "lesavka_server"
-version = "0.26.1"
+version = "0.26.2"
 dependencies = [
  "anyhow",
  "base64",
diff --git a/client/Cargo.toml b/client/Cargo.toml
index 4724ffc..1affe8a 100644
--- a/client/Cargo.toml
+++ b/client/Cargo.toml
@@ -4,7 +4,7 @@ path                    = "src/main.rs"
 
 [package]
 name                    = "lesavka_client"
-version                 = "0.26.1"
+version                 = "0.26.2"
 edition                 = "2024"
 
 [dependencies]
diff --git a/common/Cargo.toml b/common/Cargo.toml
index 250f9ff..29d832b 100644
--- a/common/Cargo.toml
+++ b/common/Cargo.toml
@@ -1,6 +1,6 @@
 [package]
 name                    = "lesavka_common"
-version                 = "0.26.1"
+version                 = "0.26.2"
 edition                 = "2024"
 build                   = "build.rs"
 
diff --git a/server/Cargo.toml b/server/Cargo.toml
index 5c3a9f8..085b3e8 100644
--- a/server/Cargo.toml
+++ b/server/Cargo.toml
@@ -16,7 +16,7 @@ bench                   = false
 
 [package]
 name                    = "lesavka_server"
-version                 = "0.26.1"
+version                 = "0.26.2"
 edition                 = "2024"
 autobins                = false
 
diff --git a/server/src/video_sinks/webcam_sink.rs b/server/src/video_sinks/webcam_sink.rs
index 8146e39..540decf 100644
--- a/server/src/video_sinks/webcam_sink.rs
+++ b/server/src/video_sinks/webcam_sink.rs
@@ -47,6 +47,7 @@ pub struct WebcamSink {
     uvc_width: u16,
     uvc_height: u16,
     direct_mjpeg_profile_mismatch_seen: AtomicBool,
+    unexpected_mjpeg_in_hevc_seen: AtomicBool,
     last_decoded_mjpeg_bytes: AtomicU64,
     direct_mjpeg_normalize_bypassed: AtomicBool,
     normalized_mjpeg_miss_count: AtomicU64,
diff --git a/server/src/video_sinks/webcam_sink/constructor.rs b/server/src/video_sinks/webcam_sink/constructor.rs
index 72c09a0..774241d 100644
--- a/server/src/video_sinks/webcam_sink/constructor.rs
+++ b/server/src/video_sinks/webcam_sink/constructor.rs
@@ -62,6 +62,7 @@ impl WebcamSink {
             uvc_width: cfg.width.min(u32::from(u16::MAX)) as u16,
             uvc_height: cfg.height.min(u32::from(u16::MAX)) as u16,
             direct_mjpeg_profile_mismatch_seen: AtomicBool::new(false),
+            unexpected_mjpeg_in_hevc_seen: AtomicBool::new(false),
             last_decoded_mjpeg_bytes: AtomicU64::new(0),
             direct_mjpeg_normalize_bypassed: AtomicBool::new(false),
             normalized_mjpeg_miss_count: AtomicU64::new(0),
@@ -368,6 +369,7 @@ impl WebcamSink {
             uvc_width: cfg.width.min(u32::from(u16::MAX)) as u16,
             uvc_height: cfg.height.min(u32::from(u16::MAX)) as u16,
             direct_mjpeg_profile_mismatch_seen: AtomicBool::new(false),
+            unexpected_mjpeg_in_hevc_seen: AtomicBool::new(false),
             last_decoded_mjpeg_bytes: AtomicU64::new(0),
             direct_mjpeg_normalize_bypassed: AtomicBool::new(false),
             normalized_mjpeg_miss_count: AtomicU64::new(0),
diff --git a/server/src/video_sinks/webcam_sink/frame_handoff.rs b/server/src/video_sinks/webcam_sink/frame_handoff.rs
index c30c31a..c91c268 100644
--- a/server/src/video_sinks/webcam_sink/frame_handoff.rs
+++ b/server/src/video_sinks/webcam_sink/frame_handoff.rs
@@ -26,8 +26,24 @@ impl WebcamSink {
 
     #[cfg(not(coverage))]
     pub fn push(&self, pkt: VideoPacket) {
+        let packet_is_mjpeg = looks_like_mjpeg_frame(&pkt.data);
+        if packet_is_mjpeg && self.decoded_mjpeg_sink.is_some() {
+            if !self
+                .unexpected_mjpeg_in_hevc_seen
+                .swap(true, Ordering::Relaxed)
+            {
+                warn!(
+                    target:"lesavka_server::video",
+                    bytes = pkt.data.len(),
+                    pts = pkt.pts,
+                    "dropping MJPEG packet received while HEVC UVC decoder is active; restart or update the upstream client so it emits HEVC"
+                );
+            }
+            return;
+        }
+
         if let Some(path) = &self.mjpeg_spool_path
-            && looks_like_mjpeg_frame(&pkt.data)
+            && packet_is_mjpeg
         {
             self.spool_direct_mjpeg_frame(path, &pkt);
             return;