Verify 50 fps backends and decode all frames during display catch-up

tools/chatgui/src/call_video_engine.cpp

@@ -257,7 +257,7 @@ void CallVideoEngine::transmit() {
     // Не связываем приём с наличием собственного encoder.
     for (unsigned codec = 1; codec <= 2 && m->running; ++codec) {
         for (const QSize size : {QSize(1920, 1080), QSize(1280, 720)}) {
-          for (unsigned fps : {30u, 60u}) {
+          for (unsigned fps : {30u, 50u, 60u}) {
             const bool fullhd = size.width() == 1920;
             call_video_format probe{1, (uint16_t)size.width(), (uint16_t)size.height(), (uint16_t)fps, 0, (uint8_t)codec,
                 (uint8_t)(codec == 1 ? (fullhd ? (fps > 30 ? 42 : 40) : (fps > 30 ? 32 : 31))