Why Won't My Movie Disc Restart Where I Stopped It? OR, A Steaming Mug of BD Java!

One of the biggest, conceptual changes introduced with Blu-ray discs (and continued with UHD Blu-ray discs) was the idea the Studio could include computer program code -- software -- ON the disc, which would load and run whenever you played that disc, and which would CONTROL that playback.  No longer would disc playback be strictly limited to the "user interface" features implemented by each, different, Blu-ray player!  So long as the player could run the on-disc software, the DISC could invent its OWN user interface!  There was nothing like this for prior, SD-DVD discs.

This on-disc software would be written in a variant of the Java programming language to be called "BD-J" (Blu-ray Disc Java).  The expectations for how Studios would use BD Java were truly grand -- to begin with.  All sorts of fancy features were proposed to "enhance" the customer value of these discs.  The actual result has been rather a mixed bag.  In particular, some Studios seem to be most keen on how BD Java can be used to make a disc really difficult to copy -- something which has NOTHING to do with the customer’s experience.

In this post I'll talk about BD Java, and how it relates to the perennial complaint: My disc player won't let me do Resume Play on my movie!

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Digital Video, OR "Lost in Color Space!"

Few things cause as much confusion among Home Theater enthusiasts as the myriad details surrounding Digital Video formats. It is typical to run into settings choices, for example, which come with no useful explanation, nor even advice as to when or why you might prefer one over another. It is also typical to run into non-intuitive limitations: You can't do THIS because you are also trying to do THAT!

In this post, I will attempt to survey the entire topic of Digital Video formats as applied to Home Theater systems. There's way too much material here to cover everything in one post, but I will try to show you how the pieces fit together, and introduce the jargon you will see repeatedly in future posts as I get into more details.

So if you've ever wondered just what, "HDMI 4K/24 YCbCr 4:2:2 12-bit HDR10 BT.2020 with HDCP 2.2" actually MEANS (and why the heck you'd need to KNOW that), this post is for you!

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