Keep a converted frame for encoder reconfiguration

tools/chatgui/src/stream_publish_engine.cpp

@@ -103,6 +103,7 @@ struct StreamPublishEngine::Impl {
 #endif
     std::unique_ptr<QWindowCapture> window;
     QImage frame;
+    QImage latestImage;
     QVideoFrame previewFrame;
     QVideoFrame presentedPreview;
     int64_t lastImageCaptureAt = 0;
@@ -282,7 +283,7 @@ bool StreamPublishEngine::openSource(const StreamPublishConfig& config) {
         {
             std::lock_guard<std::mutex> guard(m->lock);
             if (!m->running || generation != m->sourceGeneration) return;
-            m->frame = std::move(image); m->framePts = framePts; m->frameGeneration = m->generation;
+            m->latestImage = image; m->frame = std::move(image); m->framePts = framePts; m->frameGeneration = m->generation;
         }
         m->wake.notify_all();
     }, Qt::DirectConnection);
@@ -414,7 +415,8 @@ void StreamPublishEngine::closeSource() {
     if (m->screen) { disconnect(m->screen.get(), nullptr, this, nullptr); m->screen->stop(); }
     if (m->window) { disconnect(m->window.get(), nullptr, this, nullptr); m->window->stop(); }
     m->session.reset(); m->camera.reset(); m->screen.reset(); m->window.reset(); m->sink.reset();
-    std::lock_guard<std::mutex> guard(m->lock); m->frame = {}; m->previewFrame = {}; m->presentedPreview = {}; m->framePts = -1;
+    std::lock_guard<std::mutex> guard(m->lock);
+    m->frame = {}; m->latestImage = {}; m->previewFrame = {}; m->presentedPreview = {}; m->framePts = -1;
 #endif
 }
 
@@ -491,7 +493,7 @@ bool StreamPublishEngine::reconfigure(const StreamPublishConfig& config) {
         && (config.video.width != previous.video.width || config.video.height != previous.video.height || config.video.fps != previous.video.fps));
     { std::lock_guard<std::mutex> guard(m->lock); m->wanted = config; m->generation++; m->started = monotonicUs(); m->softwareRequest = 0;
 #ifdef HAVE_STREAM_CAPTURE
-      if (!sourceChange) m->frameGeneration = m->generation;
+      if (!sourceChange) { m->frame = m->latestImage; m->frameGeneration = m->generation; }
 #endif
     }
     if (sourceChange && !openSource(config)) { sourceFailed(m->generation, text("Could not open the selected video source")); return false; }