Assemble partial codec setup and test real out of band decoder configuration

tools/chatgui/tests/test_stream_view.cpp

@@ -265,6 +265,7 @@ private slots:
             AVCodecContext* context = avcodec_alloc_context3(encoder); QVERIFY(context);
             context->width = 160; context->height = 90; context->pix_fmt = AV_PIX_FMT_YUV420P; context->bit_rate = 200000;
             context->time_base = {1, 30}; context->framerate = {30, 1}; context->max_b_frames = 0; context->thread_count = 1; context->gop_size = 1;
+            context->flags |= AV_CODEC_FLAG_GLOBAL_HEADER;
             AVDictionary* options = nullptr;
             if (fixture.type == STREAM_MEDIA_H265) {
                 av_dict_set(&options, "preset", "ultrafast", 0); av_dict_set(&options, "tune", "zerolatency", 0);