fix(video): fix video stream freezing on capture re-init (e.g. pipewire display switch) (#5249)

Co-authored-by: psyke83 <psyke83@users.noreply.github.com>

src/platform/linux/pipewire.cpp

@@ -136,16 +136,12 @@ namespace pipewire {
 
     ~pipewire_t() {
       BOOST_LOG(debug) << "[pipewire] Destroying pipewire_t"sv;
-      if (loop) {
-        BOOST_LOG(debug) << "[pipewire] Stop PW thread loop"sv;
-        pw_thread_loop_stop(loop);
-      }
       try {
         cleanup_stream();
       } catch (const std::exception &e) {
-        BOOST_LOG(error) << "[pipewire] Standard exception caught in ~pipewire_t: "sv << e.what();
+        BOOST_LOG(error) << "[pipewire] Standard exception caught in ~pipewire_t cleanup_stream: "sv << e.what();
       } catch (...) {
-        BOOST_LOG(error) << "[pipewire] Unknown exception caught in ~pipewire_t"sv;
+        BOOST_LOG(error) << "[pipewire] Unknown exception caught in ~pipewire_t cleanup_stream"sv;
       }
 
       pw_thread_loop_lock(loop);
@@ -533,8 +529,13 @@ namespace pipewire {
     };
 
     static void on_stream_state_changed(void *user_data, enum pw_stream_state old, enum pw_stream_state state, const char *err_msg) {
-      BOOST_LOG(debug) << "[pipewire] PipeWire stream state: " << pw_stream_state_as_string(old)
-                       << " -> " << pw_stream_state_as_string(state);
+      if (err_msg != nullptr) {
+        BOOST_LOG(info) << "[pipewire] PipeWire stream error '" << err_msg << "' on state: " << pw_stream_state_as_string(old)
+                        << " -> " << pw_stream_state_as_string(state);
+      } else {
+        BOOST_LOG(info) << "[pipewire] PipeWire stream state: " << pw_stream_state_as_string(old)
+                        << " -> " << pw_stream_state_as_string(state);
+      }
 
       auto *d = static_cast<stream_data_t *>(user_data);
 
@@ -1003,18 +1004,18 @@ namespace pipewire {
           case platf::capture_e::timeout:
             if (!pull_free_image_cb(img_out)) {
               // Detect if shutdown is pending
-              BOOST_LOG(debug) << "[pipewire] PipeWire: timeout -> interrupt nudge";
+              BOOST_LOG(debug) << "[pipewire] PipeWire: timeout -> shutdown pending -> interrupt nudge";
               pipewire.frame_cv().notify_all();
               return platf::capture_e::interrupted;
             }
             if (!push_captured_image_cb(std::move(img_out), false)) {
-              BOOST_LOG(debug) << "[pipewire] PipeWire: !push_captured_image_cb -> ok";
+              BOOST_LOG(debug) << "[pipewire] PipeWire: timeout -> !push_captured_image_cb -> ok";
               return platf::capture_e::ok;
             }
             break;
           case platf::capture_e::ok:
             if (!push_captured_image_cb(std::move(img_out), true)) {
-              BOOST_LOG(debug) << "[pipewire] PipeWire: !push_captured_image_cb -> ok";
+              BOOST_LOG(debug) << "[pipewire] PipeWire: ok -> !push_captured_image_cb -> ok";
               return platf::capture_e::ok;
             }
             break;

src/thread_safe.h

@@ -49,6 +49,21 @@ namespace safe {
       _cv.notify_all();
     }
 
+    /**
+     * @brief Try to remove and return the next queued item without any further wait
+     *
+     * @return Removed queue item, or empty result when the queue is stopped or empty.
+     */
+    status_t try_pop() {
+      std::lock_guard lg {_lock};
+      if (!_status) {
+        return util::false_v<status_t>;
+      }
+      auto val = std::move(_status);
+      _status = util::false_v<status_t>;
+      return val;
+    }
+
     // pop and view should not be used interchangeably
     /**
      * @brief Remove and return the next queued item, waiting when requested.
@@ -94,7 +109,7 @@ namespace safe {
       }
 
       auto val = std::move(_status);
-      _status.reset();
+      _status = util::false_v<status_t>;
       return val;
     }
 

src/video.cpp

@@ -1697,8 +1697,7 @@ namespace video {
                   continue;
                 }
 
-                while (capture_ctx->images->peek()) {
-                  capture_ctx->images->pop();
+                while (capture_ctx->images->try_pop()) {
                 }
 
                 ++capture_ctx;