When authoring a Blu-ray project recently for a client requiring a Playlist, we discovered a terrible bug with Encore.

Using one of our templates, the project consisted of 8 different videos which would need to be; a) accessed individually, b) all played through in sequence once, and c) all looped indefinitely.

To achieve this, we created separate timelines for each video. We also could have placed all the videos on a single timeline and used a Chapter Playlist, but it wasn’t necessary and Adobe only recently supported Chapter Playlists for Blu-ray and I don’t quite trust them yet.

So we had 4 buttons on the Main Menu. The 1st linked directly to a timeline (main feature). The 2nd button, “Play All”,  links to a Playlist that plays through all the videos then returns to the menu. A 3rd button, “Loop All” links to a different playlist that plays through all the videos with an end action linking to itself (creating an indefinite loop). And a 4th button linking to the Bonus Features Menu where the remaining 7 videos can be accessed individually.

Initially the menu works correctly until you access one of the Playlists, either the “Play All” or the “Loop All”. Once you click on one of those, they will work correctly until you attempt to return to the menu. After returning to the menu, everything gets messed up. The 1st button (which links directly to a video) plays the wrong video, the “Play All” and “Loop All” start from a different timeline than they are suppose to, and when clicking on the Bonus Features Menu, after the transition completes, it takes you to one of the timelines instead of the Bonus Features Menu. The programming was completely broken.

We decided to analyze the programming of the disc in BDedit to figure out why this was happening. For those of you that aren’t familiar with the Blu-ray specification, I’ll try and make it easy to understand…

So on a Blu-ray disc, there are lines of code that tell the player what video or menu to display, and the player also allows the code to store numbers in a database called “GPR’s” so that it can reference those numbers later on. GPR’s are used for a variety of purposes, such as storing which button to highlight when returning to a menu, which subtitle track you want, or even which video or menu will be played next.

Encore has a specific method for how it loads the next video (or menu). GPR3 stores the numeric value of the queued video or menu which is to play next, and GPR4 is used to activate that video at the proper time (the value of GPR3 is loaded into GPR4, and then Video #GPR4 is played).

The problem we discovered is that Encore was programming the disc to check and see if there was a value stored in GPR3 before loading any of those videos, playlists, or menus we were linking to, and if GPR3 contained a value other than zero, it would play the video in GPR3 instead of the intended video or menu. So to make that more simple to understand (hopefully), Encore is telling the player “wait, before you play the video/menu they want, check and see if there is a video in the queue, and if there is a video in the queue, play that instead”.

Needless to say, once we understood what Encore was doing, it was very easy to remove those several lines of code that checked GPR3 for a value before continuing. This had to be done for each of the buttons on the main menu, as well as the Main Menu button on the Bonus Features Menu.

If any of you would like more technical details on what we did so you can perform this fix yourself on your own project, or if you would like us to fix your project for you (service fee applies), please contact us. We may also create a tutorial if there is enough demand.