feat(vaapi): add option to enable strict enforcement of frame size (#3332)

* feat(vaapi): add option to enable strict enforcement of frame size

* Eliminate the QP fallback code that was only required for VAAPI

src/config.cpp

@@ -377,6 +377,10 @@ namespace config {
       -1,
     },  // vt
 
+    {
+      false,  // strict_rc_buffer
+    },  // vaapi
+
     {},  // capture
     {},  // encoder
     {},  // adapter_name
@@ -1014,6 +1018,8 @@ namespace config {
     int_f(vars, "vt_software", video.vt.vt_require_sw, vt::force_software_from_view);
     int_f(vars, "vt_realtime", video.vt.vt_realtime, vt::rt_from_view);
 
+    bool_f(vars, "vaapi_strict_rc_buffer", video.vaapi.strict_rc_buffer);
+
     string_f(vars, "capture", video.capture);
     string_f(vars, "encoder", video.encoder);
     string_f(vars, "adapter_name", video.adapter_name);