proxy: improved UI on proxy menu

app/codec/ffmpeg/ffmpegdecoder.cpp

@@ -760,6 +760,12 @@ bool FFmpegDecoder::ProxyVideo(const QAtomicInt *cancelled, int divider)
     futures.append(future);
   }
 
+  // Wait for all conversions to finish
+  for (int i=0;i<futures.size();i++) {
+    futures[i].waitForFinished();
+  }
+
+  // If succeeded, update the video stream's proxy state
   if (succeeded) {
     QFile index_output(proxy_filename);
 
@@ -773,11 +779,6 @@ bool FFmpegDecoder::ProxyVideo(const QAtomicInt *cancelled, int divider)
     video_stream->set_proxy(divider, frame_index);
   }
 
-  // Wait for all conversions to finish
-  for (int i=0;i<futures.size();i++) {
-    futures[i].waitForFinished();
-  }
-
   sws_freeContext(scaler);
 
   av_packet_free(&pkt);

app/render/backend/videorenderframecache.cpp

@@ -148,8 +148,14 @@ const QMap<rational, QByteArray> &VideoRenderFrameCache::time_hash_map() const
 QString VideoRenderFrameCache::GetFormatExtension(const PixelFormat::Format &f)
 {
   if (PixelFormat::FormatIsFloat(f)) {
+    // EXR is only fast with float buffers so we only use it for those
     return QStringLiteral(".exr");
   } else {
+    // FIXME: Will probably need different codec here. JPEG is the fastest and smallest by far (much
+    //        more so than TIFF or PNG) and we don't mind lossy for the offline cache, but JPEG
+    //        doesn't support >8-bit or alpha channels. JPEG2000 does, but my OIIO wasn't compiled
+    //        with it and I imagine it's not common in general. Still, this works well for now as a
+    //        prototype.
     return QStringLiteral(".jpg");
   }
 }

app/widget/projectexplorer/projectexplorer.cpp

@@ -310,6 +310,14 @@ void ProjectExplorer::ShowContextMenu()
           proxy_menu->addAction(tr("1/4"))->setData(4);
           proxy_menu->addAction(tr("1/8"))->setData(8);
 
+          foreach (QAction* a, proxy_menu->actions()) {
+            a->setCheckable(true);
+
+            if (a->data() == video_stream->using_proxy()) {
+              a->setChecked(true);
+            }
+          }
+
           connect(proxy_menu, &Menu::triggered, this, &ProjectExplorer::ContextMenuStartProxy);
 
         }
@@ -395,9 +403,21 @@ void ProjectExplorer::ContextMenuStartProxy(QAction *a)
     return;
   }
 
-  if (video_stream->try_start_proxy()) {
-    ProxyTask* proxy_task = new ProxyTask(video_stream, a->data().toInt());
-    TaskManager::instance()->AddTask(proxy_task);
+  int chosen_proxy_setting = a->data().toInt();
+
+  if (chosen_proxy_setting != video_stream->using_proxy()) {
+    if (!a->data().toInt()) {
+
+      // 0 means disable the proxy
+      video_stream->set_proxy(0, QVector<int64_t>());
+
+    } else if (video_stream->try_start_proxy()) {
+
+      // Start a background task for proxying
+      ProxyTask* proxy_task = new ProxyTask(video_stream, a->data().toInt());
+      TaskManager::instance()->AddTask(proxy_task);
+
+    }
   }
 }