I would like to add all MP4 features that are popular. I hardly have enough time to add super geek features because then x264/MP4 would already be a full time job and no time would be left for anything else. I don't like adding subtitles support if it requires ocr but if it's popular I would even add that. I wish there was tools to mux vobsub subtitles because then I might not have to add mkv support. I like mkv and I like adding useful features but hardly have time to add and maintain 1000 features in particular if the features try to achieve similar things. I rather try to do one thing right than doing 100 different half baked things. Can vobsub muxing tools be expected in the near future for MP4?