The extract_allowed_surface_formats function just check whether we can support some kind of surface/image format pair. We just need to create a surface, create an image with the same video-format and putImage from image to surface. All these operations success, that kind of video-format is supported. The old manner do not work for some kind of video-format. For example, the RGBA kind of format will create a NV12 surface and RGBA image, and the putImage will fail because the format is not same. And so the RGBA format is not supported but actually it is supported.