I'll be sharing what I've been trying with the DVD protocol these days:
I tried to remux/transmux the test ISO files into different video file formats. I tried working on mkv,mpg,avi etc. Well, there were some issue with timestamps while converting into the mkv file format and so it failed. Transmuxing into avi and mpg worked but they would keep looping over a few seconds of video throughout. Thanks to my mentor's help I was able to fix that problem...the dvd_seek function was not working properly. I had also added some menu functionality in hopes of making the remuxing work properly but it didnt turn out so useful. So,currently I am cleaning up the protocol code and also trying to learn git the right way (I always try to evade learning git and end up messing things up :-/). Thats all for now :-)

Happy New Year everyone! Here are a few updates on the project :
Well it was finally decided that an input device might not be the correct choice for DVD support since the libdvd* libraries do not provide sufficient abstraction to convert the DVD data into separate packets and then send them as individual streams. Sooo...I am back to working on the original DVD protocol patch. Now as far as I understand the protocols in FFmpeg are basically used to read data from the given file (in this case dvd) and then pass it on to a demuxer. I've been working with the protocol and one major problem that has surfaced is that the MPEG streams that are finally demuxed by the mpeg demuxer do not show any subtitles stream (I know, it breaks my heart too :-/ ) . Apart from that the code seems to be in need of a few tweaks the patch being quite an old one (2009 :O ). Currently I'm testing it with the changes my mentor has suggested to keep the whole thing to a bare minimum while achieving the desired functionality. That's all for the time being. I'll keep updating :)