Rémi Bernon (@rbernon) commented about dlls/winegstreamer/video_decoder.c:
{ mf_media_type_to_wg_format(decoder->output_type, &output_format);
output_format.u.video.width = frame_size >> 32;
output_format.u.video.height = (UINT32)frame_size;
I don't think you need to change this, this is a generic video decoder that's only used for Indeo codec for now (but ideally could be later used to factor more decoders).