Conversion of Frame Packed FHD3D to Frame Sequential 3D

Structure of Frame Packing 3D

Frame Packing refers to the combination of two frames, one for the left eye and the other for the right eye, into a single “packed” frame that consists of these two individual sub-frames. The key difference of a Frame Packing signal is that each sub-frame for each eye is still at full resolution, i.e., 1920×1080 for a 1080p Frame Packing signal, and 1280×720 for 720p Frame Packing 3D content.

In the case of the top-and-bottom Frame Packing 1080p format, it is referred to Full High Definition 3D or FHD3D. Read more about this format in our article on the Frame Packed FHD3D specification. The FHD3D format is one of the mandatory 3D formats specified in HDMI 1.4, which means that all HDMI 1.4 compliant displays will need to be able to handle this Frame packing format. The figure below depicts the Frame Packing FHD3D format. As you can see, this format consists of 2 – 1080p sub-frames, one for each eye, that are stacked vertically with a 45 pixel active blanking space.

Composition of a Full HD 3D (FHD3D) Frame Packing Frame

As you might imagine, you can also have Frame Packing using the Side-by-Side 3D methodwhere each sub-frame still maintains full 1080p (or 720p) resolution. However, full resolution, Frame Packing, Side-by-Side 3D is not a mandatory format in the HDMI 1.4 specification, so manufacturers do not have to support it (although they can, if they wish to). For this reason, 3D Blu-ray movie content will be outputted in the Full HD 3D Frame Packing format at 24 frames-per-second.

Displaying 3D Frame Packing Content

Once your HDMI 1.4 compliant TV receives the Frame Packed 3D signal, it will convert it internally into frame sequential 3D as shown in the diagram below. This process consists of reading a single packed frame, and splitting it into its constituent left and right sub-frame and then displaying them on the screen in a frame sequential manner. As mentioned above, the advantage of Frame Packed 3D is that each frame for each eye that is displayed on your TV has full HD resolution.

Conversion of Frame Packed FHD3D to Frame Sequential 3D

Since Frame Packing formats are double the size of standard 2D HD content, they are not backwards compatible with HDMI 1.3 devices. On the other hand, Frame Compatible 3Dformats downsample the resolution of each subframe by half along one dimension to produce a Side-by-Side 3D or Top-and-Bottom 3D frame that has the same resolution of regular 2D HD content. This is why they are known as Frame compatible and can be backwards compatible with HDMI 1.3 devices. Learn more about Frame Compatible 3D in our guide on this format.