Mia culpa. Winter spirits penning down for me these days ;-)
I feel it was copied from a DVD, and not an original BR mastering though I brought DDLJ BR from amazon. Other BRs are giving 720p (ACER5370BD) resolution including hindi movies like Veerzara and Dhoom , but somehow DDLJ is still in DVD quality.
Others are giving 720 because your projector is limited to 720p max resolution so it is downscaling from 1080.
I still cant believe how u cud get ddlj BD so bad ? It is highly improbable. Does your display actually show 480p or 576 (pal/ntsc variant) for the same? If it does then definitely some packaging mistake and they ve piut dvd in BD cover but i still dont believe that things happens.
I have a BD drive as well and if you want i can attach few screenshots of my BD for you to compare here let me know if that will help.